From b045f6918e7828941a61b551eaa3bdf4bf9fc058 Mon Sep 17 00:00:00 2001
From: YeonGyu-Kim <code.yeon.gyu@gmail.com>
Date: Fri, 5 Dec 2025 22:51:46 +0900
Subject: [PATCH] feat(lsp): add result limits to prevent token overflow

- Add DEFAULT_MAX_REFERENCES, DEFAULT_MAX_SYMBOLS, DEFAULT_MAX_DIAGNOSTICS (200 each)
- Apply limits to lsp_find_references, lsp_document_symbols, lsp_workspace_symbols, lsp_diagnostics
- Show truncation warning when results exceed limits
---
 src/tools/lsp/constants.ts |  4 +++
 src/tools/lsp/tools.ts     | 54 +++++++++++++++++++++++++++++++-------
 2 files changed, 48 insertions(+), 10 deletions(-)

diff --git a/src/tools/lsp/constants.ts b/src/tools/lsp/constants.ts
index a001a36..5b2fa97 100644
--- a/src/tools/lsp/constants.ts
+++ b/src/tools/lsp/constants.ts
@@ -36,6 +36,10 @@ export const SEVERITY_MAP: Record<number, string> = {
   4: "hint",
 }
 
+export const DEFAULT_MAX_REFERENCES = 200
+export const DEFAULT_MAX_SYMBOLS = 200
+export const DEFAULT_MAX_DIAGNOSTICS = 200
+
 export const BUILTIN_SERVERS: Record<string, Omit<LSPServerConfig, "id">> = {
   typescript: {
     command: ["typescript-language-server", "--stdio"],
diff --git a/src/tools/lsp/tools.ts b/src/tools/lsp/tools.ts
index f30f47c..68a7458 100644
--- a/src/tools/lsp/tools.ts
+++ b/src/tools/lsp/tools.ts
@@ -1,5 +1,10 @@
 import { tool } from "@opencode-ai/plugin/tool"
 import { getAllServers } from "./config"
+import {
+  DEFAULT_MAX_REFERENCES,
+  DEFAULT_MAX_SYMBOLS,
+  DEFAULT_MAX_DIAGNOSTICS,
+} from "./constants"
 import {
   withLspClient,
   formatHoverResult,
@@ -112,7 +117,14 @@ export const lsp_find_references = tool({
         return output
       }
 
-      const output = result.map(formatLocation).join("\n")
+      const total = result.length
+      const truncated = total > DEFAULT_MAX_REFERENCES
+      const limited = truncated ? result.slice(0, DEFAULT_MAX_REFERENCES) : result
+      const lines = limited.map(formatLocation)
+      if (truncated) {
+        lines.unshift(`Found ${total} references (showing first ${DEFAULT_MAX_REFERENCES}):`)
+      }
+      const output = lines.join("\n")
       return output
     } catch (e) {
       const output = `Error: ${e instanceof Error ? e.message : String(e)}`
@@ -138,13 +150,21 @@ export const lsp_document_symbols = tool({
         return output
       }
 
-      let output: string
-      if ("range" in result[0]) {
-        output = (result as DocumentSymbol[]).map((s) => formatDocumentSymbol(s)).join("\n")
-      } else {
-        output = (result as SymbolInfo[]).map(formatSymbolInfo).join("\n")
+      const total = result.length
+      const truncated = total > DEFAULT_MAX_SYMBOLS
+      const limited = truncated ? result.slice(0, DEFAULT_MAX_SYMBOLS) : result
+
+      const lines: string[] = []
+      if (truncated) {
+        lines.push(`Found ${total} symbols (showing first ${DEFAULT_MAX_SYMBOLS}):`)
       }
-      return output
+
+      if ("range" in limited[0]) {
+        lines.push(...(limited as DocumentSymbol[]).map((s) => formatDocumentSymbol(s)))
+      } else {
+        lines.push(...(limited as SymbolInfo[]).map(formatSymbolInfo))
+      }
+      return lines.join("\n")
     } catch (e) {
       const output = `Error: ${e instanceof Error ? e.message : String(e)}`
       return output
@@ -171,8 +191,15 @@ export const lsp_workspace_symbols = tool({
         return output
       }
 
-      const limited = args.limit ? result.slice(0, args.limit) : result
-      const output = limited.map(formatSymbolInfo).join("\n")
+      const total = result.length
+      const limit = Math.min(args.limit ?? DEFAULT_MAX_SYMBOLS, DEFAULT_MAX_SYMBOLS)
+      const truncated = total > limit
+      const limited = result.slice(0, limit)
+      const lines = limited.map(formatSymbolInfo)
+      if (truncated) {
+        lines.unshift(`Found ${total} symbols (showing first ${limit}):`)
+      }
+      const output = lines.join("\n")
       return output
     } catch (e) {
       const output = `Error: ${e instanceof Error ? e.message : String(e)}`
@@ -213,7 +240,14 @@ export const lsp_diagnostics = tool({
         return output
       }
 
-      const output = diagnostics.map(formatDiagnostic).join("\n")
+      const total = diagnostics.length
+      const truncated = total > DEFAULT_MAX_DIAGNOSTICS
+      const limited = truncated ? diagnostics.slice(0, DEFAULT_MAX_DIAGNOSTICS) : diagnostics
+      const lines = limited.map(formatDiagnostic)
+      if (truncated) {
+        lines.unshift(`Found ${total} diagnostics (showing first ${DEFAULT_MAX_DIAGNOSTICS}):`)
+      }
+      const output = lines.join("\n")
       return output
     } catch (e) {
       const output = `Error: ${e instanceof Error ? e.message : String(e)}`