diff --git a/src/cli/doctor/checks/auth.test.ts b/src/cli/doctor/checks/auth.test.ts
new file mode 100644
index 0000000..7940349
--- /dev/null
+++ b/src/cli/doctor/checks/auth.test.ts
@@ -0,0 +1,114 @@
+import { describe, it, expect, spyOn, afterEach } from "bun:test"
+import * as auth from "./auth"
+
+describe("auth check", () => {
+  describe("getAuthProviderInfo", () => {
+    it("returns anthropic as always available", () => {
+      // #given anthropic provider
+      // #when getting info
+      const info = auth.getAuthProviderInfo("anthropic")
+
+      // #then should show plugin installed (builtin)
+      expect(info.id).toBe("anthropic")
+      expect(info.pluginInstalled).toBe(true)
+    })
+
+    it("returns correct name for each provider", () => {
+      // #given each provider
+      // #when getting info
+      // #then should have correct names
+      expect(auth.getAuthProviderInfo("anthropic").name).toContain("Claude")
+      expect(auth.getAuthProviderInfo("openai").name).toContain("ChatGPT")
+      expect(auth.getAuthProviderInfo("google").name).toContain("Gemini")
+    })
+  })
+
+  describe("checkAuthProvider", () => {
+    let getInfoSpy: ReturnType<typeof spyOn>
+
+    afterEach(() => {
+      getInfoSpy?.mockRestore()
+    })
+
+    it("returns pass when plugin installed", async () => {
+      // #given plugin installed
+      getInfoSpy = spyOn(auth, "getAuthProviderInfo").mockReturnValue({
+        id: "anthropic",
+        name: "Anthropic (Claude)",
+        pluginInstalled: true,
+        configured: true,
+      })
+
+      // #when checking
+      const result = await auth.checkAuthProvider("anthropic")
+
+      // #then should pass
+      expect(result.status).toBe("pass")
+    })
+
+    it("returns skip when plugin not installed", async () => {
+      // #given plugin not installed
+      getInfoSpy = spyOn(auth, "getAuthProviderInfo").mockReturnValue({
+        id: "openai",
+        name: "OpenAI (ChatGPT)",
+        pluginInstalled: false,
+        configured: false,
+      })
+
+      // #when checking
+      const result = await auth.checkAuthProvider("openai")
+
+      // #then should skip
+      expect(result.status).toBe("skip")
+      expect(result.message).toContain("not installed")
+    })
+  })
+
+  describe("checkAnthropicAuth", () => {
+    it("returns a check result", async () => {
+      // #given
+      // #when checking anthropic
+      const result = await auth.checkAnthropicAuth()
+
+      // #then should return valid result
+      expect(result.name).toBeDefined()
+      expect(["pass", "fail", "warn", "skip"]).toContain(result.status)
+    })
+  })
+
+  describe("checkOpenAIAuth", () => {
+    it("returns a check result", async () => {
+      // #given
+      // #when checking openai
+      const result = await auth.checkOpenAIAuth()
+
+      // #then should return valid result
+      expect(result.name).toBeDefined()
+      expect(["pass", "fail", "warn", "skip"]).toContain(result.status)
+    })
+  })
+
+  describe("checkGoogleAuth", () => {
+    it("returns a check result", async () => {
+      // #given
+      // #when checking google
+      const result = await auth.checkGoogleAuth()
+
+      // #then should return valid result
+      expect(result.name).toBeDefined()
+      expect(["pass", "fail", "warn", "skip"]).toContain(result.status)
+    })
+  })
+
+  describe("getAuthCheckDefinitions", () => {
+    it("returns definitions for all three providers", () => {
+      // #given
+      // #when getting definitions
+      const defs = auth.getAuthCheckDefinitions()
+
+      // #then should have 3 definitions
+      expect(defs.length).toBe(3)
+      expect(defs.every((d) => d.category === "authentication")).toBe(true)
+    })
+  })
+})
diff --git a/src/cli/doctor/checks/auth.ts b/src/cli/doctor/checks/auth.ts
new file mode 100644
index 0000000..1721a1e
--- /dev/null
+++ b/src/cli/doctor/checks/auth.ts
@@ -0,0 +1,115 @@
+import { existsSync, readFileSync } from "node:fs"
+import { homedir } from "node:os"
+import { join } from "node:path"
+import type { CheckResult, CheckDefinition, AuthProviderInfo, AuthProviderId } from "../types"
+import { CHECK_IDS, CHECK_NAMES } from "../constants"
+import { parseJsonc } from "../../../shared"
+
+const OPENCODE_CONFIG_DIR = join(homedir(), ".config", "opencode")
+const OPENCODE_JSON = join(OPENCODE_CONFIG_DIR, "opencode.json")
+const OPENCODE_JSONC = join(OPENCODE_CONFIG_DIR, "opencode.jsonc")
+
+const AUTH_PLUGINS: Record<AuthProviderId, { plugin: string; name: string }> = {
+  anthropic: { plugin: "builtin", name: "Anthropic (Claude)" },
+  openai: { plugin: "opencode-openai-codex-auth", name: "OpenAI (ChatGPT)" },
+  google: { plugin: "opencode-antigravity-auth", name: "Google (Gemini)" },
+}
+
+function getOpenCodeConfig(): { plugin?: string[] } | null {
+  const configPath = existsSync(OPENCODE_JSONC) ? OPENCODE_JSONC : OPENCODE_JSON
+  if (!existsSync(configPath)) return null
+
+  try {
+    const content = readFileSync(configPath, "utf-8")
+    return parseJsonc<{ plugin?: string[] }>(content)
+  } catch {
+    return null
+  }
+}
+
+function isPluginInstalled(plugins: string[], pluginName: string): boolean {
+  if (pluginName === "builtin") return true
+  return plugins.some((p) => p === pluginName || p.startsWith(`${pluginName}@`))
+}
+
+export function getAuthProviderInfo(providerId: AuthProviderId): AuthProviderInfo {
+  const config = getOpenCodeConfig()
+  const plugins = config?.plugin ?? []
+  const authConfig = AUTH_PLUGINS[providerId]
+
+  const pluginInstalled = isPluginInstalled(plugins, authConfig.plugin)
+
+  return {
+    id: providerId,
+    name: authConfig.name,
+    pluginInstalled,
+    configured: pluginInstalled,
+  }
+}
+
+export async function checkAuthProvider(providerId: AuthProviderId): Promise<CheckResult> {
+  const info = getAuthProviderInfo(providerId)
+  const checkId = `auth-${providerId}` as keyof typeof CHECK_NAMES
+  const checkName = CHECK_NAMES[checkId] || info.name
+
+  if (!info.pluginInstalled) {
+    return {
+      name: checkName,
+      status: "skip",
+      message: "Auth plugin not installed",
+      details: [
+        `Plugin: ${AUTH_PLUGINS[providerId].plugin}`,
+        "Run: bunx oh-my-opencode install",
+      ],
+    }
+  }
+
+  return {
+    name: checkName,
+    status: "pass",
+    message: "Auth plugin available",
+    details: [
+      providerId === "anthropic"
+        ? "Run: opencode auth login (select Anthropic)"
+        : `Plugin: ${AUTH_PLUGINS[providerId].plugin}`,
+    ],
+  }
+}
+
+export async function checkAnthropicAuth(): Promise<CheckResult> {
+  return checkAuthProvider("anthropic")
+}
+
+export async function checkOpenAIAuth(): Promise<CheckResult> {
+  return checkAuthProvider("openai")
+}
+
+export async function checkGoogleAuth(): Promise<CheckResult> {
+  return checkAuthProvider("google")
+}
+
+export function getAuthCheckDefinitions(): CheckDefinition[] {
+  return [
+    {
+      id: CHECK_IDS.AUTH_ANTHROPIC,
+      name: CHECK_NAMES[CHECK_IDS.AUTH_ANTHROPIC],
+      category: "authentication",
+      check: checkAnthropicAuth,
+      critical: false,
+    },
+    {
+      id: CHECK_IDS.AUTH_OPENAI,
+      name: CHECK_NAMES[CHECK_IDS.AUTH_OPENAI],
+      category: "authentication",
+      check: checkOpenAIAuth,
+      critical: false,
+    },
+    {
+      id: CHECK_IDS.AUTH_GOOGLE,
+      name: CHECK_NAMES[CHECK_IDS.AUTH_GOOGLE],
+      category: "authentication",
+      check: checkGoogleAuth,
+      critical: false,
+    },
+  ]
+}
diff --git a/src/cli/doctor/checks/config.test.ts b/src/cli/doctor/checks/config.test.ts
new file mode 100644
index 0000000..81129a8
--- /dev/null
+++ b/src/cli/doctor/checks/config.test.ts
@@ -0,0 +1,103 @@
+import { describe, it, expect, spyOn, afterEach } from "bun:test"
+import * as config from "./config"
+
+describe("config check", () => {
+  describe("validateConfig", () => {
+    it("returns valid: false for non-existent file", () => {
+      // #given non-existent file path
+      // #when validating
+      const result = config.validateConfig("/non/existent/path.json")
+
+      // #then should indicate invalid
+      expect(result.valid).toBe(false)
+      expect(result.errors.length).toBeGreaterThan(0)
+    })
+  })
+
+  describe("getConfigInfo", () => {
+    it("returns exists: false when no config found", () => {
+      // #given no config file exists
+      // #when getting config info
+      const info = config.getConfigInfo()
+
+      // #then should handle gracefully
+      expect(typeof info.exists).toBe("boolean")
+      expect(typeof info.valid).toBe("boolean")
+    })
+  })
+
+  describe("checkConfigValidity", () => {
+    let getInfoSpy: ReturnType<typeof spyOn>
+
+    afterEach(() => {
+      getInfoSpy?.mockRestore()
+    })
+
+    it("returns pass when no config exists (uses defaults)", async () => {
+      // #given no config file
+      getInfoSpy = spyOn(config, "getConfigInfo").mockReturnValue({
+        exists: false,
+        path: null,
+        format: null,
+        valid: true,
+        errors: [],
+      })
+
+      // #when checking validity
+      const result = await config.checkConfigValidity()
+
+      // #then should pass with default message
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("default")
+    })
+
+    it("returns pass when config is valid", async () => {
+      // #given valid config
+      getInfoSpy = spyOn(config, "getConfigInfo").mockReturnValue({
+        exists: true,
+        path: "/home/user/.config/opencode/oh-my-opencode.json",
+        format: "json",
+        valid: true,
+        errors: [],
+      })
+
+      // #when checking validity
+      const result = await config.checkConfigValidity()
+
+      // #then should pass
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("JSON")
+    })
+
+    it("returns fail when config has validation errors", async () => {
+      // #given invalid config
+      getInfoSpy = spyOn(config, "getConfigInfo").mockReturnValue({
+        exists: true,
+        path: "/home/user/.config/opencode/oh-my-opencode.json",
+        format: "json",
+        valid: false,
+        errors: ["agents.oracle: Invalid model format"],
+      })
+
+      // #when checking validity
+      const result = await config.checkConfigValidity()
+
+      // #then should fail with errors
+      expect(result.status).toBe("fail")
+      expect(result.details?.some((d) => d.includes("Error"))).toBe(true)
+    })
+  })
+
+  describe("getConfigCheckDefinition", () => {
+    it("returns valid check definition", () => {
+      // #given
+      // #when getting definition
+      const def = config.getConfigCheckDefinition()
+
+      // #then should have required properties
+      expect(def.id).toBe("config-validation")
+      expect(def.category).toBe("configuration")
+      expect(def.critical).toBe(false)
+    })
+  })
+})
diff --git a/src/cli/doctor/checks/config.ts b/src/cli/doctor/checks/config.ts
new file mode 100644
index 0000000..302e8f6
--- /dev/null
+++ b/src/cli/doctor/checks/config.ts
@@ -0,0 +1,123 @@
+import { existsSync, readFileSync } from "node:fs"
+import { homedir } from "node:os"
+import { join } from "node:path"
+import type { CheckResult, CheckDefinition, ConfigInfo } from "../types"
+import { CHECK_IDS, CHECK_NAMES, PACKAGE_NAME } from "../constants"
+import { parseJsonc, detectConfigFile } from "../../../shared"
+import { OhMyOpenCodeConfigSchema } from "../../../config"
+
+const USER_CONFIG_DIR = join(homedir(), ".config", "opencode")
+const USER_CONFIG_BASE = join(USER_CONFIG_DIR, `${PACKAGE_NAME}`)
+const PROJECT_CONFIG_BASE = join(process.cwd(), ".opencode", PACKAGE_NAME)
+
+function findConfigPath(): { path: string; format: "json" | "jsonc" } | null {
+  const projectDetected = detectConfigFile(PROJECT_CONFIG_BASE)
+  if (projectDetected.format !== "none") {
+    return { path: projectDetected.path, format: projectDetected.format as "json" | "jsonc" }
+  }
+
+  const userDetected = detectConfigFile(USER_CONFIG_BASE)
+  if (userDetected.format !== "none") {
+    return { path: userDetected.path, format: userDetected.format as "json" | "jsonc" }
+  }
+
+  return null
+}
+
+export function validateConfig(configPath: string): { valid: boolean; errors: string[] } {
+  try {
+    const content = readFileSync(configPath, "utf-8")
+    const rawConfig = parseJsonc<Record<string, unknown>>(content)
+    const result = OhMyOpenCodeConfigSchema.safeParse(rawConfig)
+
+    if (!result.success) {
+      const errors = result.error.issues.map(
+        (i) => `${i.path.join(".")}: ${i.message}`
+      )
+      return { valid: false, errors }
+    }
+
+    return { valid: true, errors: [] }
+  } catch (err) {
+    return {
+      valid: false,
+      errors: [err instanceof Error ? err.message : "Failed to parse config"],
+    }
+  }
+}
+
+export function getConfigInfo(): ConfigInfo {
+  const configPath = findConfigPath()
+
+  if (!configPath) {
+    return {
+      exists: false,
+      path: null,
+      format: null,
+      valid: true,
+      errors: [],
+    }
+  }
+
+  if (!existsSync(configPath.path)) {
+    return {
+      exists: false,
+      path: configPath.path,
+      format: configPath.format,
+      valid: true,
+      errors: [],
+    }
+  }
+
+  const validation = validateConfig(configPath.path)
+
+  return {
+    exists: true,
+    path: configPath.path,
+    format: configPath.format,
+    valid: validation.valid,
+    errors: validation.errors,
+  }
+}
+
+export async function checkConfigValidity(): Promise<CheckResult> {
+  const info = getConfigInfo()
+
+  if (!info.exists) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.CONFIG_VALIDATION],
+      status: "pass",
+      message: "Using default configuration",
+      details: ["No custom config file found (optional)"],
+    }
+  }
+
+  if (!info.valid) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.CONFIG_VALIDATION],
+      status: "fail",
+      message: "Configuration has validation errors",
+      details: [
+        `Path: ${info.path}`,
+        ...info.errors.map((e) => `Error: ${e}`),
+      ],
+    }
+  }
+
+  return {
+    name: CHECK_NAMES[CHECK_IDS.CONFIG_VALIDATION],
+    status: "pass",
+    message: `Valid ${info.format?.toUpperCase()} config`,
+    details: [`Path: ${info.path}`],
+  }
+}
+
+export function getConfigCheckDefinition(): CheckDefinition {
+  return {
+    id: CHECK_IDS.CONFIG_VALIDATION,
+    name: CHECK_NAMES[CHECK_IDS.CONFIG_VALIDATION],
+    category: "configuration",
+    check: checkConfigValidity,
+    critical: false,
+  }
+}
diff --git a/src/cli/doctor/checks/dependencies.test.ts b/src/cli/doctor/checks/dependencies.test.ts
new file mode 100644
index 0000000..523f959
--- /dev/null
+++ b/src/cli/doctor/checks/dependencies.test.ts
@@ -0,0 +1,152 @@
+import { describe, it, expect, spyOn, afterEach } from "bun:test"
+import * as deps from "./dependencies"
+
+describe("dependencies check", () => {
+  describe("checkAstGrepCli", () => {
+    it("returns dependency info", async () => {
+      // #given
+      // #when checking ast-grep cli
+      const info = await deps.checkAstGrepCli()
+
+      // #then should return valid info
+      expect(info.name).toBe("AST-Grep CLI")
+      expect(info.required).toBe(false)
+      expect(typeof info.installed).toBe("boolean")
+    })
+  })
+
+  describe("checkAstGrepNapi", () => {
+    it("returns dependency info", () => {
+      // #given
+      // #when checking ast-grep napi
+      const info = deps.checkAstGrepNapi()
+
+      // #then should return valid info
+      expect(info.name).toBe("AST-Grep NAPI")
+      expect(info.required).toBe(false)
+      expect(typeof info.installed).toBe("boolean")
+    })
+  })
+
+  describe("checkCommentChecker", () => {
+    it("returns dependency info", async () => {
+      // #given
+      // #when checking comment checker
+      const info = await deps.checkCommentChecker()
+
+      // #then should return valid info
+      expect(info.name).toBe("Comment Checker")
+      expect(info.required).toBe(false)
+      expect(typeof info.installed).toBe("boolean")
+    })
+  })
+
+  describe("checkDependencyAstGrepCli", () => {
+    let checkSpy: ReturnType<typeof spyOn>
+
+    afterEach(() => {
+      checkSpy?.mockRestore()
+    })
+
+    it("returns pass when installed", async () => {
+      // #given ast-grep installed
+      checkSpy = spyOn(deps, "checkAstGrepCli").mockResolvedValue({
+        name: "AST-Grep CLI",
+        required: false,
+        installed: true,
+        version: "0.25.0",
+        path: "/usr/local/bin/sg",
+      })
+
+      // #when checking
+      const result = await deps.checkDependencyAstGrepCli()
+
+      // #then should pass
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("0.25.0")
+    })
+
+    it("returns warn when not installed", async () => {
+      // #given ast-grep not installed
+      checkSpy = spyOn(deps, "checkAstGrepCli").mockResolvedValue({
+        name: "AST-Grep CLI",
+        required: false,
+        installed: false,
+        version: null,
+        path: null,
+        installHint: "Install: npm install -g @ast-grep/cli",
+      })
+
+      // #when checking
+      const result = await deps.checkDependencyAstGrepCli()
+
+      // #then should warn (optional)
+      expect(result.status).toBe("warn")
+      expect(result.message).toContain("optional")
+    })
+  })
+
+  describe("checkDependencyAstGrepNapi", () => {
+    let checkSpy: ReturnType<typeof spyOn>
+
+    afterEach(() => {
+      checkSpy?.mockRestore()
+    })
+
+    it("returns pass when installed", async () => {
+      // #given napi installed
+      checkSpy = spyOn(deps, "checkAstGrepNapi").mockReturnValue({
+        name: "AST-Grep NAPI",
+        required: false,
+        installed: true,
+        version: null,
+        path: null,
+      })
+
+      // #when checking
+      const result = await deps.checkDependencyAstGrepNapi()
+
+      // #then should pass
+      expect(result.status).toBe("pass")
+    })
+  })
+
+  describe("checkDependencyCommentChecker", () => {
+    let checkSpy: ReturnType<typeof spyOn>
+
+    afterEach(() => {
+      checkSpy?.mockRestore()
+    })
+
+    it("returns warn when not installed", async () => {
+      // #given comment checker not installed
+      checkSpy = spyOn(deps, "checkCommentChecker").mockResolvedValue({
+        name: "Comment Checker",
+        required: false,
+        installed: false,
+        version: null,
+        path: null,
+        installHint: "Hook will be disabled if not available",
+      })
+
+      // #when checking
+      const result = await deps.checkDependencyCommentChecker()
+
+      // #then should warn
+      expect(result.status).toBe("warn")
+    })
+  })
+
+  describe("getDependencyCheckDefinitions", () => {
+    it("returns definitions for all dependencies", () => {
+      // #given
+      // #when getting definitions
+      const defs = deps.getDependencyCheckDefinitions()
+
+      // #then should have 3 definitions
+      expect(defs.length).toBe(3)
+      expect(defs.every((d) => d.category === "dependencies")).toBe(true)
+      expect(defs.every((d) => d.critical === false)).toBe(true)
+    })
+  })
+})
diff --git a/src/cli/doctor/checks/dependencies.ts b/src/cli/doctor/checks/dependencies.ts
new file mode 100644
index 0000000..2a941a8
--- /dev/null
+++ b/src/cli/doctor/checks/dependencies.ts
@@ -0,0 +1,163 @@
+import type { CheckResult, CheckDefinition, DependencyInfo } from "../types"
+import { CHECK_IDS, CHECK_NAMES } from "../constants"
+
+async function checkBinaryExists(binary: string): Promise<{ exists: boolean; path: string | null }> {
+  try {
+    const proc = Bun.spawn(["which", binary], { stdout: "pipe", stderr: "pipe" })
+    const output = await new Response(proc.stdout).text()
+    await proc.exited
+    if (proc.exitCode === 0) {
+      return { exists: true, path: output.trim() }
+    }
+  } catch {
+    // intentionally empty - binary not found
+  }
+  return { exists: false, path: null }
+}
+
+async function getBinaryVersion(binary: string): Promise<string | null> {
+  try {
+    const proc = Bun.spawn([binary, "--version"], { stdout: "pipe", stderr: "pipe" })
+    const output = await new Response(proc.stdout).text()
+    await proc.exited
+    if (proc.exitCode === 0) {
+      return output.trim().split("\n")[0]
+    }
+  } catch {
+    // intentionally empty - version unavailable
+  }
+  return null
+}
+
+export async function checkAstGrepCli(): Promise<DependencyInfo> {
+  const binaryCheck = await checkBinaryExists("sg")
+  const altBinaryCheck = !binaryCheck.exists ? await checkBinaryExists("ast-grep") : null
+
+  const binary = binaryCheck.exists ? binaryCheck : altBinaryCheck
+  if (!binary || !binary.exists) {
+    return {
+      name: "AST-Grep CLI",
+      required: false,
+      installed: false,
+      version: null,
+      path: null,
+      installHint: "Install: npm install -g @ast-grep/cli",
+    }
+  }
+
+  const version = await getBinaryVersion(binary.path!)
+
+  return {
+    name: "AST-Grep CLI",
+    required: false,
+    installed: true,
+    version,
+    path: binary.path,
+  }
+}
+
+export function checkAstGrepNapi(): DependencyInfo {
+  try {
+    require.resolve("@ast-grep/napi")
+    return {
+      name: "AST-Grep NAPI",
+      required: false,
+      installed: true,
+      version: null,
+      path: null,
+    }
+  } catch {
+    return {
+      name: "AST-Grep NAPI",
+      required: false,
+      installed: false,
+      version: null,
+      path: null,
+      installHint: "Will use CLI fallback if available",
+    }
+  }
+}
+
+export async function checkCommentChecker(): Promise<DependencyInfo> {
+  const binaryCheck = await checkBinaryExists("comment-checker")
+
+  if (!binaryCheck.exists) {
+    return {
+      name: "Comment Checker",
+      required: false,
+      installed: false,
+      version: null,
+      path: null,
+      installHint: "Hook will be disabled if not available",
+    }
+  }
+
+  const version = await getBinaryVersion("comment-checker")
+
+  return {
+    name: "Comment Checker",
+    required: false,
+    installed: true,
+    version,
+    path: binaryCheck.path,
+  }
+}
+
+function dependencyToCheckResult(dep: DependencyInfo, checkName: string): CheckResult {
+  if (dep.installed) {
+    return {
+      name: checkName,
+      status: "pass",
+      message: dep.version ?? "installed",
+      details: dep.path ? [`Path: ${dep.path}`] : undefined,
+    }
+  }
+
+  return {
+    name: checkName,
+    status: "warn",
+    message: "Not installed (optional)",
+    details: dep.installHint ? [dep.installHint] : undefined,
+  }
+}
+
+export async function checkDependencyAstGrepCli(): Promise<CheckResult> {
+  const info = await checkAstGrepCli()
+  return dependencyToCheckResult(info, CHECK_NAMES[CHECK_IDS.DEP_AST_GREP_CLI])
+}
+
+export async function checkDependencyAstGrepNapi(): Promise<CheckResult> {
+  const info = checkAstGrepNapi()
+  return dependencyToCheckResult(info, CHECK_NAMES[CHECK_IDS.DEP_AST_GREP_NAPI])
+}
+
+export async function checkDependencyCommentChecker(): Promise<CheckResult> {
+  const info = await checkCommentChecker()
+  return dependencyToCheckResult(info, CHECK_NAMES[CHECK_IDS.DEP_COMMENT_CHECKER])
+}
+
+export function getDependencyCheckDefinitions(): CheckDefinition[] {
+  return [
+    {
+      id: CHECK_IDS.DEP_AST_GREP_CLI,
+      name: CHECK_NAMES[CHECK_IDS.DEP_AST_GREP_CLI],
+      category: "dependencies",
+      check: checkDependencyAstGrepCli,
+      critical: false,
+    },
+    {
+      id: CHECK_IDS.DEP_AST_GREP_NAPI,
+      name: CHECK_NAMES[CHECK_IDS.DEP_AST_GREP_NAPI],
+      category: "dependencies",
+      check: checkDependencyAstGrepNapi,
+      critical: false,
+    },
+    {
+      id: CHECK_IDS.DEP_COMMENT_CHECKER,
+      name: CHECK_NAMES[CHECK_IDS.DEP_COMMENT_CHECKER],
+      category: "dependencies",
+      check: checkDependencyCommentChecker,
+      critical: false,
+    },
+  ]
+}
diff --git a/src/cli/doctor/checks/index.ts b/src/cli/doctor/checks/index.ts
new file mode 100644
index 0000000..09457f5
--- /dev/null
+++ b/src/cli/doctor/checks/index.ts
@@ -0,0 +1,31 @@
+import type { CheckDefinition } from "../types"
+import { getOpenCodeCheckDefinition } from "./opencode"
+import { getPluginCheckDefinition } from "./plugin"
+import { getConfigCheckDefinition } from "./config"
+import { getAuthCheckDefinitions } from "./auth"
+import { getDependencyCheckDefinitions } from "./dependencies"
+import { getLspCheckDefinition } from "./lsp"
+import { getMcpCheckDefinitions } from "./mcp"
+import { getVersionCheckDefinition } from "./version"
+
+export * from "./opencode"
+export * from "./plugin"
+export * from "./config"
+export * from "./auth"
+export * from "./dependencies"
+export * from "./lsp"
+export * from "./mcp"
+export * from "./version"
+
+export function getAllCheckDefinitions(): CheckDefinition[] {
+  return [
+    getOpenCodeCheckDefinition(),
+    getPluginCheckDefinition(),
+    getConfigCheckDefinition(),
+    ...getAuthCheckDefinitions(),
+    ...getDependencyCheckDefinitions(),
+    getLspCheckDefinition(),
+    ...getMcpCheckDefinitions(),
+    getVersionCheckDefinition(),
+  ]
+}
diff --git a/src/cli/doctor/checks/lsp.test.ts b/src/cli/doctor/checks/lsp.test.ts
new file mode 100644
index 0000000..b266cc0
--- /dev/null
+++ b/src/cli/doctor/checks/lsp.test.ts
@@ -0,0 +1,117 @@
+import { describe, it, expect, spyOn, afterEach } from "bun:test"
+import * as lsp from "./lsp"
+import type { LspServerInfo } from "../types"
+
+describe("lsp check", () => {
+  describe("getLspServersInfo", () => {
+    it("returns array of server info", async () => {
+      // #given
+      // #when getting servers info
+      const servers = await lsp.getLspServersInfo()
+
+      // #then should return array with expected structure
+      expect(Array.isArray(servers)).toBe(true)
+      servers.forEach((s) => {
+        expect(s.id).toBeDefined()
+        expect(typeof s.installed).toBe("boolean")
+        expect(Array.isArray(s.extensions)).toBe(true)
+      })
+    })
+  })
+
+  describe("getLspServerStats", () => {
+    it("counts installed servers correctly", () => {
+      // #given servers with mixed installation status
+      const servers = [
+        { id: "ts", installed: true, extensions: [".ts"], source: "builtin" as const },
+        { id: "py", installed: false, extensions: [".py"], source: "builtin" as const },
+        { id: "go", installed: true, extensions: [".go"], source: "builtin" as const },
+      ]
+
+      // #when getting stats
+      const stats = lsp.getLspServerStats(servers)
+
+      // #then should count correctly
+      expect(stats.installed).toBe(2)
+      expect(stats.total).toBe(3)
+    })
+
+    it("handles empty array", () => {
+      // #given no servers
+      const servers: LspServerInfo[] = []
+
+      // #when getting stats
+      const stats = lsp.getLspServerStats(servers)
+
+      // #then should return zeros
+      expect(stats.installed).toBe(0)
+      expect(stats.total).toBe(0)
+    })
+  })
+
+  describe("checkLspServers", () => {
+    let getServersSpy: ReturnType<typeof spyOn>
+
+    afterEach(() => {
+      getServersSpy?.mockRestore()
+    })
+
+    it("returns warn when no servers installed", async () => {
+      // #given no servers installed
+      getServersSpy = spyOn(lsp, "getLspServersInfo").mockResolvedValue([
+        { id: "typescript-language-server", installed: false, extensions: [".ts"], source: "builtin" },
+        { id: "pyright", installed: false, extensions: [".py"], source: "builtin" },
+      ])
+
+      // #when checking
+      const result = await lsp.checkLspServers()
+
+      // #then should warn
+      expect(result.status).toBe("warn")
+      expect(result.message).toContain("No LSP servers")
+    })
+
+    it("returns pass when servers installed", async () => {
+      // #given some servers installed
+      getServersSpy = spyOn(lsp, "getLspServersInfo").mockResolvedValue([
+        { id: "typescript-language-server", installed: true, extensions: [".ts"], source: "builtin" },
+        { id: "pyright", installed: false, extensions: [".py"], source: "builtin" },
+      ])
+
+      // #when checking
+      const result = await lsp.checkLspServers()
+
+      // #then should pass with count
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("1/2")
+    })
+
+    it("lists installed and missing servers in details", async () => {
+      // #given mixed installation
+      getServersSpy = spyOn(lsp, "getLspServersInfo").mockResolvedValue([
+        { id: "typescript-language-server", installed: true, extensions: [".ts"], source: "builtin" },
+        { id: "pyright", installed: false, extensions: [".py"], source: "builtin" },
+      ])
+
+      // #when checking
+      const result = await lsp.checkLspServers()
+
+      // #then should list both
+      expect(result.details?.some((d) => d.includes("Installed"))).toBe(true)
+      expect(result.details?.some((d) => d.includes("Not found"))).toBe(true)
+    })
+  })
+
+  describe("getLspCheckDefinition", () => {
+    it("returns valid check definition", () => {
+      // #given
+      // #when getting definition
+      const def = lsp.getLspCheckDefinition()
+
+      // #then should have required properties
+      expect(def.id).toBe("lsp-servers")
+      expect(def.category).toBe("tools")
+      expect(def.critical).toBe(false)
+    })
+  })
+})
diff --git a/src/cli/doctor/checks/lsp.ts b/src/cli/doctor/checks/lsp.ts
new file mode 100644
index 0000000..70350ed
--- /dev/null
+++ b/src/cli/doctor/checks/lsp.ts
@@ -0,0 +1,85 @@
+import type { CheckResult, CheckDefinition, LspServerInfo } from "../types"
+import { CHECK_IDS, CHECK_NAMES } from "../constants"
+
+const DEFAULT_LSP_SERVERS: Array<{
+  id: string
+  binary: string
+  extensions: string[]
+}> = [
+  { id: "typescript-language-server", binary: "typescript-language-server", extensions: [".ts", ".tsx", ".js", ".jsx"] },
+  { id: "pyright", binary: "pyright-langserver", extensions: [".py"] },
+  { id: "rust-analyzer", binary: "rust-analyzer", extensions: [".rs"] },
+  { id: "gopls", binary: "gopls", extensions: [".go"] },
+]
+
+async function checkBinaryExists(binary: string): Promise<boolean> {
+  try {
+    const proc = Bun.spawn(["which", binary], { stdout: "pipe", stderr: "pipe" })
+    await proc.exited
+    return proc.exitCode === 0
+  } catch {
+    return false
+  }
+}
+
+export async function getLspServersInfo(): Promise<LspServerInfo[]> {
+  const servers: LspServerInfo[] = []
+
+  for (const server of DEFAULT_LSP_SERVERS) {
+    const installed = await checkBinaryExists(server.binary)
+    servers.push({
+      id: server.id,
+      installed,
+      extensions: server.extensions,
+      source: "builtin",
+    })
+  }
+
+  return servers
+}
+
+export function getLspServerStats(servers: LspServerInfo[]): { installed: number; total: number } {
+  const installed = servers.filter((s) => s.installed).length
+  return { installed, total: servers.length }
+}
+
+export async function checkLspServers(): Promise<CheckResult> {
+  const servers = await getLspServersInfo()
+  const stats = getLspServerStats(servers)
+  const installedServers = servers.filter((s) => s.installed)
+  const missingServers = servers.filter((s) => !s.installed)
+
+  if (stats.installed === 0) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.LSP_SERVERS],
+      status: "warn",
+      message: "No LSP servers detected",
+      details: [
+        "LSP tools will have limited functionality",
+        ...missingServers.map((s) => `Missing: ${s.id}`),
+      ],
+    }
+  }
+
+  const details = [
+    ...installedServers.map((s) => `Installed: ${s.id}`),
+    ...missingServers.map((s) => `Not found: ${s.id} (optional)`),
+  ]
+
+  return {
+    name: CHECK_NAMES[CHECK_IDS.LSP_SERVERS],
+    status: "pass",
+    message: `${stats.installed}/${stats.total} servers available`,
+    details,
+  }
+}
+
+export function getLspCheckDefinition(): CheckDefinition {
+  return {
+    id: CHECK_IDS.LSP_SERVERS,
+    name: CHECK_NAMES[CHECK_IDS.LSP_SERVERS],
+    category: "tools",
+    check: checkLspServers,
+    critical: false,
+  }
+}
diff --git a/src/cli/doctor/checks/mcp.test.ts b/src/cli/doctor/checks/mcp.test.ts
new file mode 100644
index 0000000..cb8b1b6
--- /dev/null
+++ b/src/cli/doctor/checks/mcp.test.ts
@@ -0,0 +1,117 @@
+import { describe, it, expect, spyOn, afterEach } from "bun:test"
+import * as mcp from "./mcp"
+
+describe("mcp check", () => {
+  describe("getBuiltinMcpInfo", () => {
+    it("returns builtin servers", () => {
+      // #given
+      // #when getting builtin info
+      const servers = mcp.getBuiltinMcpInfo()
+
+      // #then should include expected servers
+      expect(servers.length).toBe(3)
+      expect(servers.every((s) => s.type === "builtin")).toBe(true)
+      expect(servers.every((s) => s.enabled === true)).toBe(true)
+      expect(servers.map((s) => s.id)).toContain("context7")
+      expect(servers.map((s) => s.id)).toContain("websearch_exa")
+      expect(servers.map((s) => s.id)).toContain("grep_app")
+    })
+  })
+
+  describe("getUserMcpInfo", () => {
+    it("returns empty array when no user config", () => {
+      // #given no user config exists
+      // #when getting user info
+      const servers = mcp.getUserMcpInfo()
+
+      // #then should return array (may be empty)
+      expect(Array.isArray(servers)).toBe(true)
+    })
+  })
+
+  describe("checkBuiltinMcpServers", () => {
+    it("returns pass with server count", async () => {
+      // #given
+      // #when checking builtin servers
+      const result = await mcp.checkBuiltinMcpServers()
+
+      // #then should pass
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("3")
+      expect(result.message).toContain("enabled")
+    })
+
+    it("lists enabled servers in details", async () => {
+      // #given
+      // #when checking builtin servers
+      const result = await mcp.checkBuiltinMcpServers()
+
+      // #then should list servers
+      expect(result.details?.some((d) => d.includes("context7"))).toBe(true)
+      expect(result.details?.some((d) => d.includes("websearch_exa"))).toBe(true)
+      expect(result.details?.some((d) => d.includes("grep_app"))).toBe(true)
+    })
+  })
+
+  describe("checkUserMcpServers", () => {
+    let getUserSpy: ReturnType<typeof spyOn>
+
+    afterEach(() => {
+      getUserSpy?.mockRestore()
+    })
+
+    it("returns skip when no user config", async () => {
+      // #given no user servers
+      getUserSpy = spyOn(mcp, "getUserMcpInfo").mockReturnValue([])
+
+      // #when checking
+      const result = await mcp.checkUserMcpServers()
+
+      // #then should skip
+      expect(result.status).toBe("skip")
+      expect(result.message).toContain("No user MCP")
+    })
+
+    it("returns pass when valid user servers", async () => {
+      // #given valid user servers
+      getUserSpy = spyOn(mcp, "getUserMcpInfo").mockReturnValue([
+        { id: "custom-mcp", type: "user", enabled: true, valid: true },
+      ])
+
+      // #when checking
+      const result = await mcp.checkUserMcpServers()
+
+      // #then should pass
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("1")
+    })
+
+    it("returns warn when servers have issues", async () => {
+      // #given invalid server config
+      getUserSpy = spyOn(mcp, "getUserMcpInfo").mockReturnValue([
+        { id: "bad-mcp", type: "user", enabled: true, valid: false, error: "Missing command" },
+      ])
+
+      // #when checking
+      const result = await mcp.checkUserMcpServers()
+
+      // #then should warn
+      expect(result.status).toBe("warn")
+      expect(result.details?.some((d) => d.includes("Invalid"))).toBe(true)
+    })
+  })
+
+  describe("getMcpCheckDefinitions", () => {
+    it("returns definitions for builtin and user", () => {
+      // #given
+      // #when getting definitions
+      const defs = mcp.getMcpCheckDefinitions()
+
+      // #then should have 2 definitions
+      expect(defs.length).toBe(2)
+      expect(defs.every((d) => d.category === "tools")).toBe(true)
+      expect(defs.map((d) => d.id)).toContain("mcp-builtin")
+      expect(defs.map((d) => d.id)).toContain("mcp-user")
+    })
+  })
+})
diff --git a/src/cli/doctor/checks/mcp.ts b/src/cli/doctor/checks/mcp.ts
new file mode 100644
index 0000000..ba89457
--- /dev/null
+++ b/src/cli/doctor/checks/mcp.ts
@@ -0,0 +1,128 @@
+import { existsSync, readFileSync } from "node:fs"
+import { homedir } from "node:os"
+import { join } from "node:path"
+import type { CheckResult, CheckDefinition, McpServerInfo } from "../types"
+import { CHECK_IDS, CHECK_NAMES } from "../constants"
+import { parseJsonc } from "../../../shared"
+
+const BUILTIN_MCP_SERVERS = ["context7", "websearch_exa", "grep_app"]
+
+const MCP_CONFIG_PATHS = [
+  join(homedir(), ".claude", ".mcp.json"),
+  join(process.cwd(), ".mcp.json"),
+  join(process.cwd(), ".claude", ".mcp.json"),
+]
+
+interface McpConfig {
+  mcpServers?: Record<string, unknown>
+}
+
+function loadUserMcpConfig(): Record<string, unknown> {
+  const servers: Record<string, unknown> = {}
+
+  for (const configPath of MCP_CONFIG_PATHS) {
+    if (!existsSync(configPath)) continue
+
+    try {
+      const content = readFileSync(configPath, "utf-8")
+      const config = parseJsonc<McpConfig>(content)
+      if (config.mcpServers) {
+        Object.assign(servers, config.mcpServers)
+      }
+    } catch {
+      // intentionally empty - skip invalid configs
+    }
+  }
+
+  return servers
+}
+
+export function getBuiltinMcpInfo(): McpServerInfo[] {
+  return BUILTIN_MCP_SERVERS.map((id) => ({
+    id,
+    type: "builtin" as const,
+    enabled: true,
+    valid: true,
+  }))
+}
+
+export function getUserMcpInfo(): McpServerInfo[] {
+  const userServers = loadUserMcpConfig()
+  const servers: McpServerInfo[] = []
+
+  for (const [id, config] of Object.entries(userServers)) {
+    const isValid = typeof config === "object" && config !== null
+    servers.push({
+      id,
+      type: "user",
+      enabled: true,
+      valid: isValid,
+      error: isValid ? undefined : "Invalid configuration format",
+    })
+  }
+
+  return servers
+}
+
+export async function checkBuiltinMcpServers(): Promise<CheckResult> {
+  const servers = getBuiltinMcpInfo()
+
+  return {
+    name: CHECK_NAMES[CHECK_IDS.MCP_BUILTIN],
+    status: "pass",
+    message: `${servers.length} built-in servers enabled`,
+    details: servers.map((s) => `Enabled: ${s.id}`),
+  }
+}
+
+export async function checkUserMcpServers(): Promise<CheckResult> {
+  const servers = getUserMcpInfo()
+
+  if (servers.length === 0) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.MCP_USER],
+      status: "skip",
+      message: "No user MCP configuration found",
+      details: ["Optional: Add .mcp.json for custom MCP servers"],
+    }
+  }
+
+  const invalidServers = servers.filter((s) => !s.valid)
+  if (invalidServers.length > 0) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.MCP_USER],
+      status: "warn",
+      message: `${invalidServers.length} server(s) have configuration issues`,
+      details: [
+        ...servers.filter((s) => s.valid).map((s) => `Valid: ${s.id}`),
+        ...invalidServers.map((s) => `Invalid: ${s.id} - ${s.error}`),
+      ],
+    }
+  }
+
+  return {
+    name: CHECK_NAMES[CHECK_IDS.MCP_USER],
+    status: "pass",
+    message: `${servers.length} user server(s) configured`,
+    details: servers.map((s) => `Configured: ${s.id}`),
+  }
+}
+
+export function getMcpCheckDefinitions(): CheckDefinition[] {
+  return [
+    {
+      id: CHECK_IDS.MCP_BUILTIN,
+      name: CHECK_NAMES[CHECK_IDS.MCP_BUILTIN],
+      category: "tools",
+      check: checkBuiltinMcpServers,
+      critical: false,
+    },
+    {
+      id: CHECK_IDS.MCP_USER,
+      name: CHECK_NAMES[CHECK_IDS.MCP_USER],
+      category: "tools",
+      check: checkUserMcpServers,
+      critical: false,
+    },
+  ]
+}
diff --git a/src/cli/doctor/checks/opencode.test.ts b/src/cli/doctor/checks/opencode.test.ts
new file mode 100644
index 0000000..160dfcb
--- /dev/null
+++ b/src/cli/doctor/checks/opencode.test.ts
@@ -0,0 +1,139 @@
+import { describe, it, expect, spyOn, beforeEach, afterEach } from "bun:test"
+import * as opencode from "./opencode"
+import { MIN_OPENCODE_VERSION } from "../constants"
+
+describe("opencode check", () => {
+  describe("compareVersions", () => {
+    it("returns true when current >= minimum", () => {
+      // #given versions where current is greater
+      // #when comparing
+      // #then should return true
+      expect(opencode.compareVersions("1.0.200", "1.0.150")).toBe(true)
+      expect(opencode.compareVersions("1.1.0", "1.0.150")).toBe(true)
+      expect(opencode.compareVersions("2.0.0", "1.0.150")).toBe(true)
+    })
+
+    it("returns true when versions are equal", () => {
+      // #given equal versions
+      // #when comparing
+      // #then should return true
+      expect(opencode.compareVersions("1.0.150", "1.0.150")).toBe(true)
+    })
+
+    it("returns false when current < minimum", () => {
+      // #given version below minimum
+      // #when comparing
+      // #then should return false
+      expect(opencode.compareVersions("1.0.100", "1.0.150")).toBe(false)
+      expect(opencode.compareVersions("0.9.0", "1.0.150")).toBe(false)
+    })
+
+    it("handles version prefixes", () => {
+      // #given version with v prefix
+      // #when comparing
+      // #then should strip prefix and compare correctly
+      expect(opencode.compareVersions("v1.0.200", "1.0.150")).toBe(true)
+    })
+
+    it("handles prerelease versions", () => {
+      // #given prerelease version
+      // #when comparing
+      // #then should use base version
+      expect(opencode.compareVersions("1.0.200-beta.1", "1.0.150")).toBe(true)
+    })
+  })
+
+  describe("getOpenCodeInfo", () => {
+    it("returns installed: false when binary not found", async () => {
+      // #given no opencode binary
+      const spy = spyOn(opencode, "findOpenCodeBinary").mockResolvedValue(null)
+
+      // #when getting info
+      const info = await opencode.getOpenCodeInfo()
+
+      // #then should indicate not installed
+      expect(info.installed).toBe(false)
+      expect(info.version).toBeNull()
+      expect(info.path).toBeNull()
+      expect(info.binary).toBeNull()
+
+      spy.mockRestore()
+    })
+  })
+
+  describe("checkOpenCodeInstallation", () => {
+    let getInfoSpy: ReturnType<typeof spyOn>
+
+    afterEach(() => {
+      getInfoSpy?.mockRestore()
+    })
+
+    it("returns fail when not installed", async () => {
+      // #given opencode not installed
+      getInfoSpy = spyOn(opencode, "getOpenCodeInfo").mockResolvedValue({
+        installed: false,
+        version: null,
+        path: null,
+        binary: null,
+      })
+
+      // #when checking installation
+      const result = await opencode.checkOpenCodeInstallation()
+
+      // #then should fail with installation hint
+      expect(result.status).toBe("fail")
+      expect(result.message).toContain("not installed")
+      expect(result.details).toBeDefined()
+      expect(result.details?.some((d) => d.includes("opencode.ai"))).toBe(true)
+    })
+
+    it("returns warn when version below minimum", async () => {
+      // #given old version installed
+      getInfoSpy = spyOn(opencode, "getOpenCodeInfo").mockResolvedValue({
+        installed: true,
+        version: "1.0.100",
+        path: "/usr/local/bin/opencode",
+        binary: "opencode",
+      })
+
+      // #when checking installation
+      const result = await opencode.checkOpenCodeInstallation()
+
+      // #then should warn about old version
+      expect(result.status).toBe("warn")
+      expect(result.message).toContain("below minimum")
+      expect(result.details?.some((d) => d.includes(MIN_OPENCODE_VERSION))).toBe(true)
+    })
+
+    it("returns pass when properly installed", async () => {
+      // #given current version installed
+      getInfoSpy = spyOn(opencode, "getOpenCodeInfo").mockResolvedValue({
+        installed: true,
+        version: "1.0.200",
+        path: "/usr/local/bin/opencode",
+        binary: "opencode",
+      })
+
+      // #when checking installation
+      const result = await opencode.checkOpenCodeInstallation()
+
+      // #then should pass
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("1.0.200")
+    })
+  })
+
+  describe("getOpenCodeCheckDefinition", () => {
+    it("returns valid check definition", () => {
+      // #given
+      // #when getting definition
+      const def = opencode.getOpenCodeCheckDefinition()
+
+      // #then should have required properties
+      expect(def.id).toBe("opencode-installation")
+      expect(def.category).toBe("installation")
+      expect(def.critical).toBe(true)
+      expect(typeof def.check).toBe("function")
+    })
+  })
+})
diff --git a/src/cli/doctor/checks/opencode.ts b/src/cli/doctor/checks/opencode.ts
new file mode 100644
index 0000000..e6a2345
--- /dev/null
+++ b/src/cli/doctor/checks/opencode.ts
@@ -0,0 +1,118 @@
+import type { CheckResult, CheckDefinition, OpenCodeInfo } from "../types"
+import { CHECK_IDS, CHECK_NAMES, MIN_OPENCODE_VERSION, OPENCODE_BINARIES } from "../constants"
+
+export async function findOpenCodeBinary(): Promise<{ binary: string; path: string } | null> {
+  for (const binary of OPENCODE_BINARIES) {
+    try {
+      const proc = Bun.spawn(["which", binary], { stdout: "pipe", stderr: "pipe" })
+      const output = await new Response(proc.stdout).text()
+      await proc.exited
+      if (proc.exitCode === 0) {
+        return { binary, path: output.trim() }
+      }
+    } catch {
+      continue
+    }
+  }
+  return null
+}
+
+export async function getOpenCodeVersion(binary: string): Promise<string | null> {
+  try {
+    const proc = Bun.spawn([binary, "--version"], { stdout: "pipe", stderr: "pipe" })
+    const output = await new Response(proc.stdout).text()
+    await proc.exited
+    if (proc.exitCode === 0) {
+      return output.trim()
+    }
+  } catch {
+    return null
+  }
+  return null
+}
+
+export function compareVersions(current: string, minimum: string): boolean {
+  const parseVersion = (v: string): number[] => {
+    const cleaned = v.replace(/^v/, "").split("-")[0]
+    return cleaned.split(".").map((n) => parseInt(n, 10) || 0)
+  }
+
+  const curr = parseVersion(current)
+  const min = parseVersion(minimum)
+
+  for (let i = 0; i < Math.max(curr.length, min.length); i++) {
+    const c = curr[i] ?? 0
+    const m = min[i] ?? 0
+    if (c > m) return true
+    if (c < m) return false
+  }
+  return true
+}
+
+export async function getOpenCodeInfo(): Promise<OpenCodeInfo> {
+  const binaryInfo = await findOpenCodeBinary()
+
+  if (!binaryInfo) {
+    return {
+      installed: false,
+      version: null,
+      path: null,
+      binary: null,
+    }
+  }
+
+  const version = await getOpenCodeVersion(binaryInfo.binary)
+
+  return {
+    installed: true,
+    version,
+    path: binaryInfo.path,
+    binary: binaryInfo.binary as "opencode" | "opencode-desktop",
+  }
+}
+
+export async function checkOpenCodeInstallation(): Promise<CheckResult> {
+  const info = await getOpenCodeInfo()
+
+  if (!info.installed) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.OPENCODE_INSTALLATION],
+      status: "fail",
+      message: "OpenCode is not installed",
+      details: [
+        "Visit: https://opencode.ai/docs for installation instructions",
+        "Run: npm install -g opencode",
+      ],
+    }
+  }
+
+  if (info.version && !compareVersions(info.version, MIN_OPENCODE_VERSION)) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.OPENCODE_INSTALLATION],
+      status: "warn",
+      message: `Version ${info.version} is below minimum ${MIN_OPENCODE_VERSION}`,
+      details: [
+        `Current: ${info.version}`,
+        `Required: >= ${MIN_OPENCODE_VERSION}`,
+        "Run: npm update -g opencode",
+      ],
+    }
+  }
+
+  return {
+    name: CHECK_NAMES[CHECK_IDS.OPENCODE_INSTALLATION],
+    status: "pass",
+    message: info.version ?? "installed",
+    details: info.path ? [`Path: ${info.path}`] : undefined,
+  }
+}
+
+export function getOpenCodeCheckDefinition(): CheckDefinition {
+  return {
+    id: CHECK_IDS.OPENCODE_INSTALLATION,
+    name: CHECK_NAMES[CHECK_IDS.OPENCODE_INSTALLATION],
+    category: "installation",
+    check: checkOpenCodeInstallation,
+    critical: true,
+  }
+}
diff --git a/src/cli/doctor/checks/plugin.test.ts b/src/cli/doctor/checks/plugin.test.ts
new file mode 100644
index 0000000..e6a3612
--- /dev/null
+++ b/src/cli/doctor/checks/plugin.test.ts
@@ -0,0 +1,109 @@
+import { describe, it, expect, spyOn, afterEach } from "bun:test"
+import * as plugin from "./plugin"
+
+describe("plugin check", () => {
+  describe("getPluginInfo", () => {
+    it("returns registered: false when config not found", () => {
+      // #given no config file exists
+      // #when getting plugin info
+      // #then should indicate not registered
+      const info = plugin.getPluginInfo()
+      expect(typeof info.registered).toBe("boolean")
+      expect(typeof info.isPinned).toBe("boolean")
+    })
+  })
+
+  describe("checkPluginRegistration", () => {
+    let getInfoSpy: ReturnType<typeof spyOn>
+
+    afterEach(() => {
+      getInfoSpy?.mockRestore()
+    })
+
+    it("returns fail when config file not found", async () => {
+      // #given no config file
+      getInfoSpy = spyOn(plugin, "getPluginInfo").mockReturnValue({
+        registered: false,
+        configPath: null,
+        entry: null,
+        isPinned: false,
+        pinnedVersion: null,
+      })
+
+      // #when checking registration
+      const result = await plugin.checkPluginRegistration()
+
+      // #then should fail with hint
+      expect(result.status).toBe("fail")
+      expect(result.message).toContain("not found")
+    })
+
+    it("returns fail when plugin not registered", async () => {
+      // #given config exists but plugin not registered
+      getInfoSpy = spyOn(plugin, "getPluginInfo").mockReturnValue({
+        registered: false,
+        configPath: "/home/user/.config/opencode/opencode.json",
+        entry: null,
+        isPinned: false,
+        pinnedVersion: null,
+      })
+
+      // #when checking registration
+      const result = await plugin.checkPluginRegistration()
+
+      // #then should fail
+      expect(result.status).toBe("fail")
+      expect(result.message).toContain("not registered")
+    })
+
+    it("returns pass when plugin registered", async () => {
+      // #given plugin registered
+      getInfoSpy = spyOn(plugin, "getPluginInfo").mockReturnValue({
+        registered: true,
+        configPath: "/home/user/.config/opencode/opencode.json",
+        entry: "oh-my-opencode",
+        isPinned: false,
+        pinnedVersion: null,
+      })
+
+      // #when checking registration
+      const result = await plugin.checkPluginRegistration()
+
+      // #then should pass
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("Registered")
+    })
+
+    it("indicates pinned version when applicable", async () => {
+      // #given plugin pinned to version
+      getInfoSpy = spyOn(plugin, "getPluginInfo").mockReturnValue({
+        registered: true,
+        configPath: "/home/user/.config/opencode/opencode.json",
+        entry: "oh-my-opencode@2.7.0",
+        isPinned: true,
+        pinnedVersion: "2.7.0",
+      })
+
+      // #when checking registration
+      const result = await plugin.checkPluginRegistration()
+
+      // #then should show pinned version
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("pinned")
+      expect(result.message).toContain("2.7.0")
+    })
+  })
+
+  describe("getPluginCheckDefinition", () => {
+    it("returns valid check definition", () => {
+      // #given
+      // #when getting definition
+      const def = plugin.getPluginCheckDefinition()
+
+      // #then should have required properties
+      expect(def.id).toBe("plugin-registration")
+      expect(def.category).toBe("installation")
+      expect(def.critical).toBe(true)
+    })
+  })
+})
diff --git a/src/cli/doctor/checks/plugin.ts b/src/cli/doctor/checks/plugin.ts
new file mode 100644
index 0000000..05a0f85
--- /dev/null
+++ b/src/cli/doctor/checks/plugin.ts
@@ -0,0 +1,127 @@
+import { existsSync, readFileSync } from "node:fs"
+import { homedir } from "node:os"
+import { join } from "node:path"
+import type { CheckResult, CheckDefinition, PluginInfo } from "../types"
+import { CHECK_IDS, CHECK_NAMES, PACKAGE_NAME } from "../constants"
+import { parseJsonc } from "../../../shared"
+
+const OPENCODE_CONFIG_DIR = join(homedir(), ".config", "opencode")
+const OPENCODE_JSON = join(OPENCODE_CONFIG_DIR, "opencode.json")
+const OPENCODE_JSONC = join(OPENCODE_CONFIG_DIR, "opencode.jsonc")
+
+function detectConfigPath(): { path: string; format: "json" | "jsonc" } | null {
+  if (existsSync(OPENCODE_JSONC)) {
+    return { path: OPENCODE_JSONC, format: "jsonc" }
+  }
+  if (existsSync(OPENCODE_JSON)) {
+    return { path: OPENCODE_JSON, format: "json" }
+  }
+  return null
+}
+
+function findPluginEntry(plugins: string[]): { entry: string; isPinned: boolean; version: string | null } | null {
+  for (const plugin of plugins) {
+    if (plugin === PACKAGE_NAME || plugin.startsWith(`${PACKAGE_NAME}@`)) {
+      const isPinned = plugin.includes("@")
+      const version = isPinned ? plugin.split("@")[1] : null
+      return { entry: plugin, isPinned, version }
+    }
+  }
+  return null
+}
+
+export function getPluginInfo(): PluginInfo {
+  const configInfo = detectConfigPath()
+
+  if (!configInfo) {
+    return {
+      registered: false,
+      configPath: null,
+      entry: null,
+      isPinned: false,
+      pinnedVersion: null,
+    }
+  }
+
+  try {
+    const content = readFileSync(configInfo.path, "utf-8")
+    const config = parseJsonc<{ plugin?: string[] }>(content)
+    const plugins = config.plugin ?? []
+    const pluginEntry = findPluginEntry(plugins)
+
+    if (!pluginEntry) {
+      return {
+        registered: false,
+        configPath: configInfo.path,
+        entry: null,
+        isPinned: false,
+        pinnedVersion: null,
+      }
+    }
+
+    return {
+      registered: true,
+      configPath: configInfo.path,
+      entry: pluginEntry.entry,
+      isPinned: pluginEntry.isPinned,
+      pinnedVersion: pluginEntry.version,
+    }
+  } catch {
+    return {
+      registered: false,
+      configPath: configInfo.path,
+      entry: null,
+      isPinned: false,
+      pinnedVersion: null,
+    }
+  }
+}
+
+export async function checkPluginRegistration(): Promise<CheckResult> {
+  const info = getPluginInfo()
+
+  if (!info.configPath) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.PLUGIN_REGISTRATION],
+      status: "fail",
+      message: "OpenCode config file not found",
+      details: [
+        "Run: bunx oh-my-opencode install",
+        `Expected: ${OPENCODE_JSON} or ${OPENCODE_JSONC}`,
+      ],
+    }
+  }
+
+  if (!info.registered) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.PLUGIN_REGISTRATION],
+      status: "fail",
+      message: "Plugin not registered in config",
+      details: [
+        "Run: bunx oh-my-opencode install",
+        `Config: ${info.configPath}`,
+      ],
+    }
+  }
+
+  const message = info.isPinned
+    ? `Registered (pinned: ${info.pinnedVersion})`
+    : "Registered"
+
+  return {
+    name: CHECK_NAMES[CHECK_IDS.PLUGIN_REGISTRATION],
+    status: "pass",
+    message,
+    details: [`Config: ${info.configPath}`],
+  }
+}
+
+export function getPluginCheckDefinition(): CheckDefinition {
+  return {
+    id: CHECK_IDS.PLUGIN_REGISTRATION,
+    name: CHECK_NAMES[CHECK_IDS.PLUGIN_REGISTRATION],
+    category: "installation",
+    check: checkPluginRegistration,
+    critical: true,
+  }
+}
diff --git a/src/cli/doctor/checks/version.test.ts b/src/cli/doctor/checks/version.test.ts
new file mode 100644
index 0000000..c0851ff
--- /dev/null
+++ b/src/cli/doctor/checks/version.test.ts
@@ -0,0 +1,148 @@
+import { describe, it, expect, spyOn, afterEach } from "bun:test"
+import * as version from "./version"
+
+describe("version check", () => {
+  describe("getVersionInfo", () => {
+    it("returns version check info structure", async () => {
+      // #given
+      // #when getting version info
+      const info = await version.getVersionInfo()
+
+      // #then should have expected structure
+      expect(typeof info.isUpToDate).toBe("boolean")
+      expect(typeof info.isLocalDev).toBe("boolean")
+      expect(typeof info.isPinned).toBe("boolean")
+    })
+  })
+
+  describe("checkVersionStatus", () => {
+    let getInfoSpy: ReturnType<typeof spyOn>
+
+    afterEach(() => {
+      getInfoSpy?.mockRestore()
+    })
+
+    it("returns pass when in local dev mode", async () => {
+      // #given local dev mode
+      getInfoSpy = spyOn(version, "getVersionInfo").mockResolvedValue({
+        currentVersion: "local-dev",
+        latestVersion: "2.7.0",
+        isUpToDate: true,
+        isLocalDev: true,
+        isPinned: false,
+      })
+
+      // #when checking
+      const result = await version.checkVersionStatus()
+
+      // #then should pass with dev message
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("local development")
+    })
+
+    it("returns pass when pinned", async () => {
+      // #given pinned version
+      getInfoSpy = spyOn(version, "getVersionInfo").mockResolvedValue({
+        currentVersion: "2.6.0",
+        latestVersion: "2.7.0",
+        isUpToDate: true,
+        isLocalDev: false,
+        isPinned: true,
+      })
+
+      // #when checking
+      const result = await version.checkVersionStatus()
+
+      // #then should pass with pinned message
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("Pinned")
+    })
+
+    it("returns warn when unable to determine version", async () => {
+      // #given no version info
+      getInfoSpy = spyOn(version, "getVersionInfo").mockResolvedValue({
+        currentVersion: null,
+        latestVersion: "2.7.0",
+        isUpToDate: false,
+        isLocalDev: false,
+        isPinned: false,
+      })
+
+      // #when checking
+      const result = await version.checkVersionStatus()
+
+      // #then should warn
+      expect(result.status).toBe("warn")
+      expect(result.message).toContain("Unable to determine")
+    })
+
+    it("returns warn when network error", async () => {
+      // #given network error
+      getInfoSpy = spyOn(version, "getVersionInfo").mockResolvedValue({
+        currentVersion: "2.6.0",
+        latestVersion: null,
+        isUpToDate: true,
+        isLocalDev: false,
+        isPinned: false,
+      })
+
+      // #when checking
+      const result = await version.checkVersionStatus()
+
+      // #then should warn
+      expect(result.status).toBe("warn")
+      expect(result.details?.some((d) => d.includes("network"))).toBe(true)
+    })
+
+    it("returns warn when update available", async () => {
+      // #given update available
+      getInfoSpy = spyOn(version, "getVersionInfo").mockResolvedValue({
+        currentVersion: "2.6.0",
+        latestVersion: "2.7.0",
+        isUpToDate: false,
+        isLocalDev: false,
+        isPinned: false,
+      })
+
+      // #when checking
+      const result = await version.checkVersionStatus()
+
+      // #then should warn with update info
+      expect(result.status).toBe("warn")
+      expect(result.message).toContain("Update available")
+      expect(result.message).toContain("2.6.0")
+      expect(result.message).toContain("2.7.0")
+    })
+
+    it("returns pass when up to date", async () => {
+      // #given up to date
+      getInfoSpy = spyOn(version, "getVersionInfo").mockResolvedValue({
+        currentVersion: "2.7.0",
+        latestVersion: "2.7.0",
+        isUpToDate: true,
+        isLocalDev: false,
+        isPinned: false,
+      })
+
+      // #when checking
+      const result = await version.checkVersionStatus()
+
+      // #then should pass
+      expect(result.status).toBe("pass")
+      expect(result.message).toContain("Up to date")
+    })
+  })
+
+  describe("getVersionCheckDefinition", () => {
+    it("returns valid check definition", () => {
+      // #given
+      // #when getting definition
+      const def = version.getVersionCheckDefinition()
+
+      // #then should have required properties
+      expect(def.id).toBe("version-status")
+      expect(def.category).toBe("updates")
+      expect(def.critical).toBe(false)
+    })
+  })
+})
diff --git a/src/cli/doctor/checks/version.ts b/src/cli/doctor/checks/version.ts
new file mode 100644
index 0000000..b110372
--- /dev/null
+++ b/src/cli/doctor/checks/version.ts
@@ -0,0 +1,177 @@
+import { existsSync, readFileSync } from "node:fs"
+import { homedir } from "node:os"
+import { join } from "node:path"
+import type { CheckResult, CheckDefinition, VersionCheckInfo } from "../types"
+import { CHECK_IDS, CHECK_NAMES, PACKAGE_NAME } from "../constants"
+import { parseJsonc } from "../../../shared"
+
+const OPENCODE_CONFIG_DIR = join(homedir(), ".config", "opencode")
+const OPENCODE_PACKAGE_JSON = join(OPENCODE_CONFIG_DIR, "package.json")
+const OPENCODE_JSON = join(OPENCODE_CONFIG_DIR, "opencode.json")
+const OPENCODE_JSONC = join(OPENCODE_CONFIG_DIR, "opencode.jsonc")
+
+async function fetchLatestVersion(): Promise<string | null> {
+  try {
+    const res = await fetch(`https://registry.npmjs.org/${PACKAGE_NAME}/latest`, {
+      signal: AbortSignal.timeout(5000),
+    })
+    if (!res.ok) return null
+    const data = (await res.json()) as { version: string }
+    return data.version
+  } catch {
+    return null
+  }
+}
+
+function getCurrentVersion(): {
+  version: string | null
+  isLocalDev: boolean
+  isPinned: boolean
+  pinnedVersion: string | null
+} {
+  const configPath = existsSync(OPENCODE_JSONC) ? OPENCODE_JSONC : OPENCODE_JSON
+
+  if (!existsSync(configPath)) {
+    return { version: null, isLocalDev: false, isPinned: false, pinnedVersion: null }
+  }
+
+  try {
+    const content = readFileSync(configPath, "utf-8")
+    const config = parseJsonc<{ plugin?: string[] }>(content)
+    const plugins = config.plugin ?? []
+
+    for (const plugin of plugins) {
+      if (plugin.startsWith("file:") && plugin.includes(PACKAGE_NAME)) {
+        return { version: "local-dev", isLocalDev: true, isPinned: false, pinnedVersion: null }
+      }
+      if (plugin.startsWith(`${PACKAGE_NAME}@`)) {
+        const pinnedVersion = plugin.split("@")[1]
+        return { version: pinnedVersion, isLocalDev: false, isPinned: true, pinnedVersion }
+      }
+      if (plugin === PACKAGE_NAME) {
+        if (existsSync(OPENCODE_PACKAGE_JSON)) {
+          try {
+            const pkgContent = readFileSync(OPENCODE_PACKAGE_JSON, "utf-8")
+            const pkg = JSON.parse(pkgContent) as { dependencies?: Record<string, string> }
+            const depVersion = pkg.dependencies?.[PACKAGE_NAME]
+            if (depVersion) {
+              const cleanVersion = depVersion.replace(/^[\^~]/, "")
+              return { version: cleanVersion, isLocalDev: false, isPinned: false, pinnedVersion: null }
+            }
+          } catch {
+            // intentionally empty - parse errors ignored
+          }
+        }
+        return { version: null, isLocalDev: false, isPinned: false, pinnedVersion: null }
+      }
+    }
+
+    return { version: null, isLocalDev: false, isPinned: false, pinnedVersion: null }
+  } catch {
+    return { version: null, isLocalDev: false, isPinned: false, pinnedVersion: null }
+  }
+}
+
+function compareVersions(current: string, latest: string): boolean {
+  const parseVersion = (v: string): number[] => {
+    const cleaned = v.replace(/^v/, "").split("-")[0]
+    return cleaned.split(".").map((n) => parseInt(n, 10) || 0)
+  }
+
+  const curr = parseVersion(current)
+  const lat = parseVersion(latest)
+
+  for (let i = 0; i < Math.max(curr.length, lat.length); i++) {
+    const c = curr[i] ?? 0
+    const l = lat[i] ?? 0
+    if (c < l) return false
+    if (c > l) return true
+  }
+  return true
+}
+
+export async function getVersionInfo(): Promise<VersionCheckInfo> {
+  const current = getCurrentVersion()
+  const latestVersion = await fetchLatestVersion()
+
+  const isUpToDate =
+    current.isLocalDev ||
+    current.isPinned ||
+    !current.version ||
+    !latestVersion ||
+    compareVersions(current.version, latestVersion)
+
+  return {
+    currentVersion: current.version,
+    latestVersion,
+    isUpToDate,
+    isLocalDev: current.isLocalDev,
+    isPinned: current.isPinned,
+  }
+}
+
+export async function checkVersionStatus(): Promise<CheckResult> {
+  const info = await getVersionInfo()
+
+  if (info.isLocalDev) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.VERSION_STATUS],
+      status: "pass",
+      message: "Running in local development mode",
+      details: ["Using file:// protocol from config"],
+    }
+  }
+
+  if (info.isPinned) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.VERSION_STATUS],
+      status: "pass",
+      message: `Pinned to version ${info.currentVersion}`,
+      details: ["Update check skipped for pinned versions"],
+    }
+  }
+
+  if (!info.currentVersion) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.VERSION_STATUS],
+      status: "warn",
+      message: "Unable to determine current version",
+      details: ["Run: bunx oh-my-opencode get-local-version"],
+    }
+  }
+
+  if (!info.latestVersion) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.VERSION_STATUS],
+      status: "warn",
+      message: `Current: ${info.currentVersion}`,
+      details: ["Unable to check for updates (network error)"],
+    }
+  }
+
+  if (!info.isUpToDate) {
+    return {
+      name: CHECK_NAMES[CHECK_IDS.VERSION_STATUS],
+      status: "warn",
+      message: `Update available: ${info.currentVersion} -> ${info.latestVersion}`,
+      details: ["Run: cd ~/.config/opencode && bun update oh-my-opencode"],
+    }
+  }
+
+  return {
+    name: CHECK_NAMES[CHECK_IDS.VERSION_STATUS],
+    status: "pass",
+    message: `Up to date (${info.currentVersion})`,
+    details: info.latestVersion ? [`Latest: ${info.latestVersion}`] : undefined,
+  }
+}
+
+export function getVersionCheckDefinition(): CheckDefinition {
+  return {
+    id: CHECK_IDS.VERSION_STATUS,
+    name: CHECK_NAMES[CHECK_IDS.VERSION_STATUS],
+    category: "updates",
+    check: checkVersionStatus,
+    critical: false,
+  }
+}
diff --git a/src/cli/doctor/constants.ts b/src/cli/doctor/constants.ts
new file mode 100644
index 0000000..7a3d7d6
--- /dev/null
+++ b/src/cli/doctor/constants.ts
@@ -0,0 +1,70 @@
+import color from "picocolors"
+
+export const SYMBOLS = {
+  check: color.green("\u2713"),
+  cross: color.red("\u2717"),
+  warn: color.yellow("\u26A0"),
+  info: color.blue("\u2139"),
+  arrow: color.cyan("\u2192"),
+  bullet: color.dim("\u2022"),
+  skip: color.dim("\u25CB"),
+} as const
+
+export const STATUS_COLORS = {
+  pass: color.green,
+  fail: color.red,
+  warn: color.yellow,
+  skip: color.dim,
+} as const
+
+export const CHECK_IDS = {
+  OPENCODE_INSTALLATION: "opencode-installation",
+  PLUGIN_REGISTRATION: "plugin-registration",
+  CONFIG_VALIDATION: "config-validation",
+  AUTH_ANTHROPIC: "auth-anthropic",
+  AUTH_OPENAI: "auth-openai",
+  AUTH_GOOGLE: "auth-google",
+  DEP_AST_GREP_CLI: "dep-ast-grep-cli",
+  DEP_AST_GREP_NAPI: "dep-ast-grep-napi",
+  DEP_COMMENT_CHECKER: "dep-comment-checker",
+  LSP_SERVERS: "lsp-servers",
+  MCP_BUILTIN: "mcp-builtin",
+  MCP_USER: "mcp-user",
+  VERSION_STATUS: "version-status",
+} as const
+
+export const CHECK_NAMES: Record<string, string> = {
+  [CHECK_IDS.OPENCODE_INSTALLATION]: "OpenCode Installation",
+  [CHECK_IDS.PLUGIN_REGISTRATION]: "Plugin Registration",
+  [CHECK_IDS.CONFIG_VALIDATION]: "Configuration Validity",
+  [CHECK_IDS.AUTH_ANTHROPIC]: "Anthropic (Claude) Auth",
+  [CHECK_IDS.AUTH_OPENAI]: "OpenAI (ChatGPT) Auth",
+  [CHECK_IDS.AUTH_GOOGLE]: "Google (Gemini) Auth",
+  [CHECK_IDS.DEP_AST_GREP_CLI]: "AST-Grep CLI",
+  [CHECK_IDS.DEP_AST_GREP_NAPI]: "AST-Grep NAPI",
+  [CHECK_IDS.DEP_COMMENT_CHECKER]: "Comment Checker",
+  [CHECK_IDS.LSP_SERVERS]: "LSP Servers",
+  [CHECK_IDS.MCP_BUILTIN]: "Built-in MCP Servers",
+  [CHECK_IDS.MCP_USER]: "User MCP Configuration",
+  [CHECK_IDS.VERSION_STATUS]: "Version Status",
+} as const
+
+export const CATEGORY_NAMES: Record<string, string> = {
+  installation: "Installation",
+  configuration: "Configuration",
+  authentication: "Authentication",
+  dependencies: "Dependencies",
+  tools: "Tools & Servers",
+  updates: "Updates",
+} as const
+
+export const EXIT_CODES = {
+  SUCCESS: 0,
+  FAILURE: 1,
+} as const
+
+export const MIN_OPENCODE_VERSION = "1.0.150"
+
+export const PACKAGE_NAME = "oh-my-opencode"
+
+export const OPENCODE_BINARIES = ["opencode", "opencode-desktop"] as const
diff --git a/src/cli/doctor/formatter.test.ts b/src/cli/doctor/formatter.test.ts
new file mode 100644
index 0000000..062d6c6
--- /dev/null
+++ b/src/cli/doctor/formatter.test.ts
@@ -0,0 +1,218 @@
+import { describe, it, expect } from "bun:test"
+import {
+  formatStatusSymbol,
+  formatCheckResult,
+  formatCategoryHeader,
+  formatSummary,
+  formatHeader,
+  formatFooter,
+  formatJsonOutput,
+  formatBox,
+  formatHelpSuggestions,
+} from "./formatter"
+import type { CheckResult, DoctorSummary, DoctorResult } from "./types"
+
+describe("formatter", () => {
+  describe("formatStatusSymbol", () => {
+    it("returns green check for pass", () => {
+      const symbol = formatStatusSymbol("pass")
+      expect(symbol).toContain("\u2713")
+    })
+
+    it("returns red cross for fail", () => {
+      const symbol = formatStatusSymbol("fail")
+      expect(symbol).toContain("\u2717")
+    })
+
+    it("returns yellow warning for warn", () => {
+      const symbol = formatStatusSymbol("warn")
+      expect(symbol).toContain("\u26A0")
+    })
+
+    it("returns dim circle for skip", () => {
+      const symbol = formatStatusSymbol("skip")
+      expect(symbol).toContain("\u25CB")
+    })
+  })
+
+  describe("formatCheckResult", () => {
+    it("includes name and message", () => {
+      const result: CheckResult = {
+        name: "Test Check",
+        status: "pass",
+        message: "All good",
+      }
+
+      const output = formatCheckResult(result, false)
+
+      expect(output).toContain("Test Check")
+      expect(output).toContain("All good")
+    })
+
+    it("includes details when verbose", () => {
+      const result: CheckResult = {
+        name: "Test Check",
+        status: "pass",
+        message: "OK",
+        details: ["Detail 1", "Detail 2"],
+      }
+
+      const output = formatCheckResult(result, true)
+
+      expect(output).toContain("Detail 1")
+      expect(output).toContain("Detail 2")
+    })
+
+    it("hides details when not verbose", () => {
+      const result: CheckResult = {
+        name: "Test Check",
+        status: "pass",
+        message: "OK",
+        details: ["Detail 1"],
+      }
+
+      const output = formatCheckResult(result, false)
+
+      expect(output).not.toContain("Detail 1")
+    })
+  })
+
+  describe("formatCategoryHeader", () => {
+    it("formats category name with styling", () => {
+      const header = formatCategoryHeader("installation")
+
+      expect(header).toContain("Installation")
+    })
+  })
+
+  describe("formatSummary", () => {
+    it("shows all counts", () => {
+      const summary: DoctorSummary = {
+        total: 10,
+        passed: 7,
+        failed: 1,
+        warnings: 2,
+        skipped: 0,
+        duration: 150,
+      }
+
+      const output = formatSummary(summary)
+
+      expect(output).toContain("7 passed")
+      expect(output).toContain("1 failed")
+      expect(output).toContain("2 warnings")
+      expect(output).toContain("10 checks")
+      expect(output).toContain("150ms")
+    })
+  })
+
+  describe("formatHeader", () => {
+    it("includes doctor branding", () => {
+      const header = formatHeader()
+
+      expect(header).toContain("Doctor")
+    })
+  })
+
+  describe("formatFooter", () => {
+    it("shows error message when failures", () => {
+      const summary: DoctorSummary = {
+        total: 5,
+        passed: 4,
+        failed: 1,
+        warnings: 0,
+        skipped: 0,
+        duration: 100,
+      }
+
+      const footer = formatFooter(summary)
+
+      expect(footer).toContain("Issues detected")
+    })
+
+    it("shows warning message when warnings only", () => {
+      const summary: DoctorSummary = {
+        total: 5,
+        passed: 4,
+        failed: 0,
+        warnings: 1,
+        skipped: 0,
+        duration: 100,
+      }
+
+      const footer = formatFooter(summary)
+
+      expect(footer).toContain("warnings")
+    })
+
+    it("shows success message when all pass", () => {
+      const summary: DoctorSummary = {
+        total: 5,
+        passed: 5,
+        failed: 0,
+        warnings: 0,
+        skipped: 0,
+        duration: 100,
+      }
+
+      const footer = formatFooter(summary)
+
+      expect(footer).toContain("operational")
+    })
+  })
+
+  describe("formatJsonOutput", () => {
+    it("returns valid JSON", () => {
+      const result: DoctorResult = {
+        results: [{ name: "Test", status: "pass", message: "OK" }],
+        summary: { total: 1, passed: 1, failed: 0, warnings: 0, skipped: 0, duration: 50 },
+        exitCode: 0,
+      }
+
+      const output = formatJsonOutput(result)
+      const parsed = JSON.parse(output)
+
+      expect(parsed.results.length).toBe(1)
+      expect(parsed.summary.total).toBe(1)
+      expect(parsed.exitCode).toBe(0)
+    })
+  })
+
+  describe("formatBox", () => {
+    it("wraps content in box", () => {
+      const box = formatBox("Test content")
+
+      expect(box).toContain("Test content")
+      expect(box).toContain("\u2500")
+    })
+
+    it("includes title when provided", () => {
+      const box = formatBox("Content", "My Title")
+
+      expect(box).toContain("My Title")
+    })
+  })
+
+  describe("formatHelpSuggestions", () => {
+    it("extracts suggestions from failed checks", () => {
+      const results: CheckResult[] = [
+        { name: "Test", status: "fail", message: "Error", details: ["Run: fix-command"] },
+        { name: "OK", status: "pass", message: "Good" },
+      ]
+
+      const suggestions = formatHelpSuggestions(results)
+
+      expect(suggestions).toContain("Run: fix-command")
+    })
+
+    it("returns empty array when no failures", () => {
+      const results: CheckResult[] = [
+        { name: "OK", status: "pass", message: "Good" },
+      ]
+
+      const suggestions = formatHelpSuggestions(results)
+
+      expect(suggestions.length).toBe(0)
+    })
+  })
+})
diff --git a/src/cli/doctor/formatter.ts b/src/cli/doctor/formatter.ts
new file mode 100644
index 0000000..976a328
--- /dev/null
+++ b/src/cli/doctor/formatter.ts
@@ -0,0 +1,140 @@
+import color from "picocolors"
+import type { CheckResult, DoctorSummary, CheckCategory, DoctorResult } from "./types"
+import { SYMBOLS, STATUS_COLORS, CATEGORY_NAMES } from "./constants"
+
+export function formatStatusSymbol(status: CheckResult["status"]): string {
+  switch (status) {
+    case "pass":
+      return SYMBOLS.check
+    case "fail":
+      return SYMBOLS.cross
+    case "warn":
+      return SYMBOLS.warn
+    case "skip":
+      return SYMBOLS.skip
+  }
+}
+
+export function formatCheckResult(result: CheckResult, verbose: boolean): string {
+  const symbol = formatStatusSymbol(result.status)
+  const colorFn = STATUS_COLORS[result.status]
+  const name = colorFn(result.name)
+  const message = color.dim(result.message)
+
+  let line = `  ${symbol} ${name}`
+  if (result.message) {
+    line += ` ${SYMBOLS.arrow} ${message}`
+  }
+
+  if (verbose && result.details && result.details.length > 0) {
+    const detailLines = result.details.map((d) => `      ${SYMBOLS.bullet} ${color.dim(d)}`).join("\n")
+    line += "\n" + detailLines
+  }
+
+  return line
+}
+
+export function formatCategoryHeader(category: CheckCategory): string {
+  const name = CATEGORY_NAMES[category] || category
+  return `\n${color.bold(color.white(name))}\n${color.dim("\u2500".repeat(40))}`
+}
+
+export function formatSummary(summary: DoctorSummary): string {
+  const lines: string[] = []
+
+  lines.push(color.bold(color.white("Summary")))
+  lines.push(color.dim("\u2500".repeat(40)))
+  lines.push("")
+
+  const passText = summary.passed > 0 ? color.green(`${summary.passed} passed`) : color.dim("0 passed")
+  const failText = summary.failed > 0 ? color.red(`${summary.failed} failed`) : color.dim("0 failed")
+  const warnText = summary.warnings > 0 ? color.yellow(`${summary.warnings} warnings`) : color.dim("0 warnings")
+  const skipText = summary.skipped > 0 ? color.dim(`${summary.skipped} skipped`) : ""
+
+  const parts = [passText, failText, warnText]
+  if (skipText) parts.push(skipText)
+
+  lines.push(`  ${parts.join(", ")}`)
+  lines.push(`  ${color.dim(`Total: ${summary.total} checks in ${summary.duration}ms`)}`)
+
+  return lines.join("\n")
+}
+
+export function formatHeader(): string {
+  return `\n${color.bgMagenta(color.white(" oMoMoMoMo... Doctor "))}\n`
+}
+
+export function formatFooter(summary: DoctorSummary): string {
+  if (summary.failed > 0) {
+    return `\n${SYMBOLS.cross} ${color.red("Issues detected. Please review the errors above.")}\n`
+  }
+  if (summary.warnings > 0) {
+    return `\n${SYMBOLS.warn} ${color.yellow("All systems operational with warnings.")}\n`
+  }
+  return `\n${SYMBOLS.check} ${color.green("All systems operational!")}\n`
+}
+
+export function formatProgress(current: number, total: number, name: string): string {
+  const progress = color.dim(`[${current}/${total}]`)
+  return `${progress} Checking ${name}...`
+}
+
+export function formatJsonOutput(result: DoctorResult): string {
+  return JSON.stringify(result, null, 2)
+}
+
+export function formatDetails(details: string[]): string {
+  return details.map((d) => `      ${SYMBOLS.bullet} ${color.dim(d)}`).join("\n")
+}
+
+function stripAnsi(str: string): string {
+  // eslint-disable-next-line no-control-regex
+  return str.replace(/\x1b\[[0-9;]*m/g, "")
+}
+
+export function formatBox(content: string, title?: string): string {
+  const lines = content.split("\n")
+  const maxWidth = Math.max(...lines.map((l) => stripAnsi(l).length), title?.length ?? 0) + 4
+  const border = color.dim("\u2500".repeat(maxWidth))
+
+  const output: string[] = []
+  output.push("")
+
+  if (title) {
+    output.push(
+      color.dim("\u250C\u2500") +
+        color.bold(` ${title} `) +
+        color.dim("\u2500".repeat(maxWidth - title.length - 4)) +
+        color.dim("\u2510")
+    )
+  } else {
+    output.push(color.dim("\u250C") + border + color.dim("\u2510"))
+  }
+
+  for (const line of lines) {
+    const stripped = stripAnsi(line)
+    const padding = maxWidth - stripped.length
+    output.push(color.dim("\u2502") + ` ${line}${" ".repeat(padding - 1)}` + color.dim("\u2502"))
+  }
+
+  output.push(color.dim("\u2514") + border + color.dim("\u2518"))
+  output.push("")
+
+  return output.join("\n")
+}
+
+export function formatHelpSuggestions(results: CheckResult[]): string[] {
+  const suggestions: string[] = []
+
+  for (const result of results) {
+    if (result.status === "fail" && result.details) {
+      for (const detail of result.details) {
+        if (detail.includes("Run:") || detail.includes("Install:") || detail.includes("Visit:")) {
+          suggestions.push(detail)
+        }
+      }
+    }
+  }
+
+  return suggestions
+}
diff --git a/src/cli/doctor/index.ts b/src/cli/doctor/index.ts
new file mode 100644
index 0000000..40de646
--- /dev/null
+++ b/src/cli/doctor/index.ts
@@ -0,0 +1,11 @@
+import type { DoctorOptions } from "./types"
+import { runDoctor } from "./runner"
+
+export async function doctor(options: DoctorOptions = {}): Promise<number> {
+  const result = await runDoctor(options)
+  return result.exitCode
+}
+
+export * from "./types"
+export { runDoctor } from "./runner"
+export { formatJsonOutput } from "./formatter"
diff --git a/src/cli/doctor/runner.test.ts b/src/cli/doctor/runner.test.ts
new file mode 100644
index 0000000..b1c3fc8
--- /dev/null
+++ b/src/cli/doctor/runner.test.ts
@@ -0,0 +1,153 @@
+import { describe, it, expect, spyOn, afterEach } from "bun:test"
+import {
+  runCheck,
+  calculateSummary,
+  determineExitCode,
+  filterChecksByCategory,
+  groupChecksByCategory,
+} from "./runner"
+import type { CheckResult, CheckDefinition, CheckCategory } from "./types"
+
+describe("runner", () => {
+  describe("runCheck", () => {
+    it("returns result from check function", async () => {
+      const check: CheckDefinition = {
+        id: "test",
+        name: "Test Check",
+        category: "installation",
+        check: async () => ({ name: "Test Check", status: "pass", message: "OK" }),
+      }
+
+      const result = await runCheck(check)
+
+      expect(result.name).toBe("Test Check")
+      expect(result.status).toBe("pass")
+    })
+
+    it("measures duration", async () => {
+      const check: CheckDefinition = {
+        id: "test",
+        name: "Test Check",
+        category: "installation",
+        check: async () => {
+          await new Promise((r) => setTimeout(r, 10))
+          return { name: "Test", status: "pass", message: "OK" }
+        },
+      }
+
+      const result = await runCheck(check)
+
+      expect(result.duration).toBeGreaterThanOrEqual(10)
+    })
+
+    it("returns fail on error", async () => {
+      const check: CheckDefinition = {
+        id: "test",
+        name: "Test Check",
+        category: "installation",
+        check: async () => {
+          throw new Error("Test error")
+        },
+      }
+
+      const result = await runCheck(check)
+
+      expect(result.status).toBe("fail")
+      expect(result.message).toContain("Test error")
+    })
+  })
+
+  describe("calculateSummary", () => {
+    it("counts each status correctly", () => {
+      const results: CheckResult[] = [
+        { name: "1", status: "pass", message: "" },
+        { name: "2", status: "pass", message: "" },
+        { name: "3", status: "fail", message: "" },
+        { name: "4", status: "warn", message: "" },
+        { name: "5", status: "skip", message: "" },
+      ]
+
+      const summary = calculateSummary(results, 100)
+
+      expect(summary.total).toBe(5)
+      expect(summary.passed).toBe(2)
+      expect(summary.failed).toBe(1)
+      expect(summary.warnings).toBe(1)
+      expect(summary.skipped).toBe(1)
+      expect(summary.duration).toBe(100)
+    })
+  })
+
+  describe("determineExitCode", () => {
+    it("returns 0 when all pass", () => {
+      const results: CheckResult[] = [
+        { name: "1", status: "pass", message: "" },
+        { name: "2", status: "pass", message: "" },
+      ]
+
+      expect(determineExitCode(results)).toBe(0)
+    })
+
+    it("returns 0 when only warnings", () => {
+      const results: CheckResult[] = [
+        { name: "1", status: "pass", message: "" },
+        { name: "2", status: "warn", message: "" },
+      ]
+
+      expect(determineExitCode(results)).toBe(0)
+    })
+
+    it("returns 1 when any failures", () => {
+      const results: CheckResult[] = [
+        { name: "1", status: "pass", message: "" },
+        { name: "2", status: "fail", message: "" },
+      ]
+
+      expect(determineExitCode(results)).toBe(1)
+    })
+  })
+
+  describe("filterChecksByCategory", () => {
+    const checks: CheckDefinition[] = [
+      { id: "1", name: "Install", category: "installation", check: async () => ({ name: "", status: "pass", message: "" }) },
+      { id: "2", name: "Config", category: "configuration", check: async () => ({ name: "", status: "pass", message: "" }) },
+      { id: "3", name: "Auth", category: "authentication", check: async () => ({ name: "", status: "pass", message: "" }) },
+    ]
+
+    it("returns all checks when no category", () => {
+      const filtered = filterChecksByCategory(checks)
+
+      expect(filtered.length).toBe(3)
+    })
+
+    it("filters to specific category", () => {
+      const filtered = filterChecksByCategory(checks, "installation")
+
+      expect(filtered.length).toBe(1)
+      expect(filtered[0].name).toBe("Install")
+    })
+  })
+
+  describe("groupChecksByCategory", () => {
+    const checks: CheckDefinition[] = [
+      { id: "1", name: "Install1", category: "installation", check: async () => ({ name: "", status: "pass", message: "" }) },
+      { id: "2", name: "Install2", category: "installation", check: async () => ({ name: "", status: "pass", message: "" }) },
+      { id: "3", name: "Config", category: "configuration", check: async () => ({ name: "", status: "pass", message: "" }) },
+    ]
+
+    it("groups checks by category", () => {
+      const groups = groupChecksByCategory(checks)
+
+      expect(groups.get("installation")?.length).toBe(2)
+      expect(groups.get("configuration")?.length).toBe(1)
+    })
+
+    it("maintains order within categories", () => {
+      const groups = groupChecksByCategory(checks)
+      const installChecks = groups.get("installation")!
+
+      expect(installChecks[0].name).toBe("Install1")
+      expect(installChecks[1].name).toBe("Install2")
+    })
+  })
+})
diff --git a/src/cli/doctor/runner.ts b/src/cli/doctor/runner.ts
new file mode 100644
index 0000000..af4c316
--- /dev/null
+++ b/src/cli/doctor/runner.ts
@@ -0,0 +1,132 @@
+import type {
+  DoctorOptions,
+  DoctorResult,
+  CheckDefinition,
+  CheckResult,
+  DoctorSummary,
+  CheckCategory,
+} from "./types"
+import { getAllCheckDefinitions } from "./checks"
+import { EXIT_CODES, CATEGORY_NAMES } from "./constants"
+import {
+  formatHeader,
+  formatCategoryHeader,
+  formatCheckResult,
+  formatSummary,
+  formatFooter,
+  formatJsonOutput,
+} from "./formatter"
+
+export async function runCheck(check: CheckDefinition): Promise<CheckResult> {
+  const start = performance.now()
+  try {
+    const result = await check.check()
+    result.duration = Math.round(performance.now() - start)
+    return result
+  } catch (err) {
+    return {
+      name: check.name,
+      status: "fail",
+      message: err instanceof Error ? err.message : "Unknown error",
+      duration: Math.round(performance.now() - start),
+    }
+  }
+}
+
+export function calculateSummary(results: CheckResult[], duration: number): DoctorSummary {
+  return {
+    total: results.length,
+    passed: results.filter((r) => r.status === "pass").length,
+    failed: results.filter((r) => r.status === "fail").length,
+    warnings: results.filter((r) => r.status === "warn").length,
+    skipped: results.filter((r) => r.status === "skip").length,
+    duration: Math.round(duration),
+  }
+}
+
+export function determineExitCode(results: CheckResult[]): number {
+  const hasFailures = results.some((r) => r.status === "fail")
+  return hasFailures ? EXIT_CODES.FAILURE : EXIT_CODES.SUCCESS
+}
+
+export function filterChecksByCategory(
+  checks: CheckDefinition[],
+  category?: CheckCategory
+): CheckDefinition[] {
+  if (!category) return checks
+  return checks.filter((c) => c.category === category)
+}
+
+export function groupChecksByCategory(
+  checks: CheckDefinition[]
+): Map<CheckCategory, CheckDefinition[]> {
+  const groups = new Map<CheckCategory, CheckDefinition[]>()
+
+  for (const check of checks) {
+    const existing = groups.get(check.category) ?? []
+    existing.push(check)
+    groups.set(check.category, existing)
+  }
+
+  return groups
+}
+
+const CATEGORY_ORDER: CheckCategory[] = [
+  "installation",
+  "configuration",
+  "authentication",
+  "dependencies",
+  "tools",
+  "updates",
+]
+
+export async function runDoctor(options: DoctorOptions): Promise<DoctorResult> {
+  const start = performance.now()
+  const allChecks = getAllCheckDefinitions()
+  const filteredChecks = filterChecksByCategory(allChecks, options.category)
+  const groupedChecks = groupChecksByCategory(filteredChecks)
+
+  const results: CheckResult[] = []
+
+  if (!options.json) {
+    console.log(formatHeader())
+  }
+
+  for (const category of CATEGORY_ORDER) {
+    const checks = groupedChecks.get(category)
+    if (!checks || checks.length === 0) continue
+
+    if (!options.json) {
+      console.log(formatCategoryHeader(category))
+    }
+
+    for (const check of checks) {
+      const result = await runCheck(check)
+      results.push(result)
+
+      if (!options.json) {
+        console.log(formatCheckResult(result, options.verbose ?? false))
+      }
+    }
+  }
+
+  const duration = performance.now() - start
+  const summary = calculateSummary(results, duration)
+  const exitCode = determineExitCode(results)
+
+  const doctorResult: DoctorResult = {
+    results,
+    summary,
+    exitCode,
+  }
+
+  if (options.json) {
+    console.log(formatJsonOutput(doctorResult))
+  } else {
+    console.log("")
+    console.log(formatSummary(summary))
+    console.log(formatFooter(summary))
+  }
+
+  return doctorResult
+}
diff --git a/src/cli/doctor/types.ts b/src/cli/doctor/types.ts
new file mode 100644
index 0000000..b512c6d
--- /dev/null
+++ b/src/cli/doctor/types.ts
@@ -0,0 +1,113 @@
+export type CheckStatus = "pass" | "fail" | "warn" | "skip"
+
+export interface CheckResult {
+  name: string
+  status: CheckStatus
+  message: string
+  details?: string[]
+  duration?: number
+}
+
+export type CheckFunction = () => Promise<CheckResult>
+
+export type CheckCategory =
+  | "installation"
+  | "configuration"
+  | "authentication"
+  | "dependencies"
+  | "tools"
+  | "updates"
+
+export interface CheckDefinition {
+  id: string
+  name: string
+  category: CheckCategory
+  check: CheckFunction
+  critical?: boolean
+}
+
+export interface DoctorOptions {
+  verbose?: boolean
+  json?: boolean
+  category?: CheckCategory
+}
+
+export interface DoctorSummary {
+  total: number
+  passed: number
+  failed: number
+  warnings: number
+  skipped: number
+  duration: number
+}
+
+export interface DoctorResult {
+  results: CheckResult[]
+  summary: DoctorSummary
+  exitCode: number
+}
+
+export interface OpenCodeInfo {
+  installed: boolean
+  version: string | null
+  path: string | null
+  binary: "opencode" | "opencode-desktop" | null
+}
+
+export interface PluginInfo {
+  registered: boolean
+  configPath: string | null
+  entry: string | null
+  isPinned: boolean
+  pinnedVersion: string | null
+}
+
+export interface ConfigInfo {
+  exists: boolean
+  path: string | null
+  format: "json" | "jsonc" | null
+  valid: boolean
+  errors: string[]
+}
+
+export type AuthProviderId = "anthropic" | "openai" | "google"
+
+export interface AuthProviderInfo {
+  id: AuthProviderId
+  name: string
+  pluginInstalled: boolean
+  configured: boolean
+  error?: string
+}
+
+export interface DependencyInfo {
+  name: string
+  required: boolean
+  installed: boolean
+  version: string | null
+  path: string | null
+  installHint?: string
+}
+
+export interface LspServerInfo {
+  id: string
+  installed: boolean
+  extensions: string[]
+  source: "builtin" | "config" | "plugin"
+}
+
+export interface McpServerInfo {
+  id: string
+  type: "builtin" | "user"
+  enabled: boolean
+  valid: boolean
+  error?: string
+}
+
+export interface VersionCheckInfo {
+  currentVersion: string | null
+  latestVersion: string | null
+  isUpToDate: boolean
+  isLocalDev: boolean
+  isPinned: boolean
+}
diff --git a/src/cli/index.ts b/src/cli/index.ts
index 6301e39..cad0e8c 100644
--- a/src/cli/index.ts
+++ b/src/cli/index.ts
@@ -3,9 +3,11 @@ import { Command } from "commander"
 import { install } from "./install"
 import { run } from "./run"
 import { getLocalVersion } from "./get-local-version"
+import { doctor } from "./doctor"
 import type { InstallArgs } from "./types"
 import type { RunOptions } from "./run"
 import type { GetLocalVersionOptions } from "./get-local-version/types"
+import type { DoctorOptions } from "./doctor"
 
 const packageJson = await import("../../package.json")
 const VERSION = packageJson.version
@@ -101,6 +103,37 @@ This command shows:
     process.exit(exitCode)
   })
 
+program
+  .command("doctor")
+  .description("Check oh-my-opencode installation health and diagnose issues")
+  .option("--verbose", "Show detailed diagnostic information")
+  .option("--json", "Output results in JSON format")
+  .option("--category <category>", "Run only specific category")
+  .addHelpText("after", `
+Examples:
+  $ bunx oh-my-opencode doctor
+  $ bunx oh-my-opencode doctor --verbose
+  $ bunx oh-my-opencode doctor --json
+  $ bunx oh-my-opencode doctor --category authentication
+
+Categories:
+  installation     Check OpenCode and plugin installation
+  configuration    Validate configuration files
+  authentication   Check auth provider status
+  dependencies     Check external dependencies
+  tools            Check LSP and MCP servers
+  updates          Check for version updates
+`)
+  .action(async (options) => {
+    const doctorOptions: DoctorOptions = {
+      verbose: options.verbose ?? false,
+      json: options.json ?? false,
+      category: options.category,
+    }
+    const exitCode = await doctor(doctorOptions)
+    process.exit(exitCode)
+  })
+
 program
   .command("version")
   .description("Show version information")