fix(recovery): implement early exit in tool output truncation

🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/hooks/anthropic-context-window-limit-recovery/storage.test.ts

@@ -0,0 +1,77 @@
+import { describe, test, expect, mock, beforeEach } from "bun:test"
+import { truncateUntilTargetTokens } from "./storage"
+import * as storage from "./storage"
+
+// Mock the entire module
+mock.module("./storage", () => {
+  return {
+    ...storage,
+    findToolResultsBySize: mock(() => []),
+    truncateToolResult: mock(() => ({ success: false })),
+  }
+})
+
+describe("truncateUntilTargetTokens", () => {
+  const sessionID = "test-session"
+  
+  beforeEach(() => {
+    // Reset mocks
+    const { findToolResultsBySize, truncateToolResult } = require("./storage")
+    findToolResultsBySize.mockReset()
+    truncateToolResult.mockReset()
+  })
+
+  test("truncates only until target is reached", () => {
+    const { findToolResultsBySize, truncateToolResult } = require("./storage")
+    
+    // #given: Two tool results, each 1000 chars. Target reduction is 500 chars.
+    const results = [
+      { partPath: "path1", partId: "id1", messageID: "m1", toolName: "tool1", outputSize: 1000 },
+      { partPath: "path2", partId: "id2", messageID: "m2", toolName: "tool2", outputSize: 1000 },
+    ]
+    
+    findToolResultsBySize.mockReturnValue(results)
+    truncateToolResult.mockImplementation((path: string) => ({
+      success: true,
+      toolName: path === "path1" ? "tool1" : "tool2",
+      originalSize: 1000
+    }))
+
+    // #when: currentTokens=1000, maxTokens=1000, targetRatio=0.5 (target=500, reduce=500)
+    // charsPerToken=1 for simplicity in test
+    const result = truncateUntilTargetTokens(sessionID, 1000, 1000, 0.5, 1)
+
+    // #then: Should only truncate the first tool
+    expect(result.truncatedCount).toBe(1)
+    expect(truncateToolResult).toHaveBeenCalledTimes(1)
+    expect(truncateToolResult).toHaveBeenCalledWith("path1")
+    expect(result.totalBytesRemoved).toBe(1000)
+    expect(result.sufficient).toBe(true)
+  })
+
+  test("truncates all if target not reached", () => {
+    const { findToolResultsBySize, truncateToolResult } = require("./storage")
+    
+    // #given: Two tool results, each 100 chars. Target reduction is 500 chars.
+    const results = [
+      { partPath: "path1", partId: "id1", messageID: "m1", toolName: "tool1", outputSize: 100 },
+      { partPath: "path2", partId: "id2", messageID: "m2", toolName: "tool2", outputSize: 100 },
+    ]
+    
+    findToolResultsBySize.mockReturnValue(results)
+    truncateToolResult.mockImplementation((path: string) => ({
+      success: true,
+      toolName: path === "path1" ? "tool1" : "tool2",
+      originalSize: 100
+    }))
+
+    // #when: reduce 500 chars
+    const result = truncateUntilTargetTokens(sessionID, 1000, 1000, 0.5, 1)
+
+    // #then: Should truncate both
+    expect(result.truncatedCount).toBe(2)
+    expect(truncateToolResult).toHaveBeenCalledTimes(2)
+    expect(result.totalBytesRemoved).toBe(200)
+    expect(result.sufficient).toBe(false)
+  })
+})

src/hooks/anthropic-context-window-limit-recovery/storage.ts

@@ -230,6 +230,10 @@ export function truncateUntilTargetTokens(
         toolName: truncateResult.toolName ?? result.toolName,
         originalSize: removedSize,
       })
+      
+      if (totalRemoved >= charsToReduce) {
+        break
+      }
     }
   }