feat: write truncated tool outputs to files (#7239)

packages/opencode/test/tool/bash.test.ts

@@ -4,6 +4,7 @@ import { BashTool } from "../../src/tool/bash"
 import { Instance } from "../../src/project/instance"
 import { tmpdir } from "../fixture/fixture"
 import type { PermissionNext } from "../../src/permission/next"
+import { Truncate } from "../../src/tool/truncation"
 
 const ctx = {
   sessionID: "test",
@@ -230,3 +231,90 @@ describe("tool.bash permissions", () => {
     })
   })
 })
+
+describe("tool.bash truncation", () => {
+  test("truncates output exceeding line limit", async () => {
+    await Instance.provide({
+      directory: projectRoot,
+      fn: async () => {
+        const bash = await BashTool.init()
+        const lineCount = Truncate.MAX_LINES + 500
+        const result = await bash.execute(
+          {
+            command: `seq 1 ${lineCount}`,
+            description: "Generate lines exceeding limit",
+          },
+          ctx,
+        )
+        expect((result.metadata as any).truncated).toBe(true)
+        expect(result.output).toContain("truncated")
+        expect(result.output).toContain("The tool call succeeded but the output was truncated")
+      },
+    })
+  })
+
+  test("truncates output exceeding byte limit", async () => {
+    await Instance.provide({
+      directory: projectRoot,
+      fn: async () => {
+        const bash = await BashTool.init()
+        const byteCount = Truncate.MAX_BYTES + 10000
+        const result = await bash.execute(
+          {
+            command: `head -c ${byteCount} /dev/zero | tr '\\0' 'a'`,
+            description: "Generate bytes exceeding limit",
+          },
+          ctx,
+        )
+        expect((result.metadata as any).truncated).toBe(true)
+        expect(result.output).toContain("truncated")
+        expect(result.output).toContain("The tool call succeeded but the output was truncated")
+      },
+    })
+  })
+
+  test("does not truncate small output", async () => {
+    await Instance.provide({
+      directory: projectRoot,
+      fn: async () => {
+        const bash = await BashTool.init()
+        const result = await bash.execute(
+          {
+            command: "echo hello",
+            description: "Echo hello",
+          },
+          ctx,
+        )
+        expect((result.metadata as any).truncated).toBe(false)
+        expect(result.output).toBe("hello\n")
+      },
+    })
+  })
+
+  test("full output is saved to file when truncated", async () => {
+    await Instance.provide({
+      directory: projectRoot,
+      fn: async () => {
+        const bash = await BashTool.init()
+        const lineCount = Truncate.MAX_LINES + 100
+        const result = await bash.execute(
+          {
+            command: `seq 1 ${lineCount}`,
+            description: "Generate lines for file check",
+          },
+          ctx,
+        )
+        expect((result.metadata as any).truncated).toBe(true)
+
+        const filepath = (result.metadata as any).outputPath
+        expect(filepath).toBeTruthy()
+
+        const saved = await Bun.file(filepath).text()
+        const lines = saved.trim().split("\n")
+        expect(lines.length).toBe(lineCount)
+        expect(lines[0]).toBe("1")
+        expect(lines[lineCount - 1]).toBe(String(lineCount))
+      },
+    })
+  })
+})

packages/opencode/test/tool/read.test.ts

@@ -6,6 +6,8 @@ import { tmpdir } from "../fixture/fixture"
 import { PermissionNext } from "../../src/permission/next"
 import { Agent } from "../../src/agent/agent"
 
+const FIXTURES_DIR = path.join(import.meta.dir, "fixtures")
+
 const ctx = {
   sessionID: "test",
   messageID: "",
@@ -165,3 +167,123 @@ describe("tool.read env file blocking", () => {
     })
   })
 })
+
+describe("tool.read truncation", () => {
+  test("truncates large file by bytes and sets truncated metadata", async () => {
+    await using tmp = await tmpdir({
+      init: async (dir) => {
+        const content = await Bun.file(path.join(FIXTURES_DIR, "models-api.json")).text()
+        await Bun.write(path.join(dir, "large.json"), content)
+      },
+    })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const read = await ReadTool.init()
+        const result = await read.execute({ filePath: path.join(tmp.path, "large.json") }, ctx)
+        expect(result.metadata.truncated).toBe(true)
+        expect(result.output).toContain("Output truncated at")
+        expect(result.output).toContain("bytes")
+      },
+    })
+  })
+
+  test("truncates by line count when limit is specified", async () => {
+    await using tmp = await tmpdir({
+      init: async (dir) => {
+        const lines = Array.from({ length: 100 }, (_, i) => `line${i}`).join("\n")
+        await Bun.write(path.join(dir, "many-lines.txt"), lines)
+      },
+    })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const read = await ReadTool.init()
+        const result = await read.execute({ filePath: path.join(tmp.path, "many-lines.txt"), limit: 10 }, ctx)
+        expect(result.metadata.truncated).toBe(true)
+        expect(result.output).toContain("File has more lines")
+        expect(result.output).toContain("line0")
+        expect(result.output).toContain("line9")
+        expect(result.output).not.toContain("line10")
+      },
+    })
+  })
+
+  test("does not truncate small file", async () => {
+    await using tmp = await tmpdir({
+      init: async (dir) => {
+        await Bun.write(path.join(dir, "small.txt"), "hello world")
+      },
+    })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const read = await ReadTool.init()
+        const result = await read.execute({ filePath: path.join(tmp.path, "small.txt") }, ctx)
+        expect(result.metadata.truncated).toBe(false)
+        expect(result.output).toContain("End of file")
+      },
+    })
+  })
+
+  test("respects offset parameter", async () => {
+    await using tmp = await tmpdir({
+      init: async (dir) => {
+        const lines = Array.from({ length: 20 }, (_, i) => `line${i}`).join("\n")
+        await Bun.write(path.join(dir, "offset.txt"), lines)
+      },
+    })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const read = await ReadTool.init()
+        const result = await read.execute({ filePath: path.join(tmp.path, "offset.txt"), offset: 10, limit: 5 }, ctx)
+        expect(result.output).toContain("line10")
+        expect(result.output).toContain("line14")
+        expect(result.output).not.toContain("line0")
+        expect(result.output).not.toContain("line15")
+      },
+    })
+  })
+
+  test("truncates long lines", async () => {
+    await using tmp = await tmpdir({
+      init: async (dir) => {
+        const longLine = "x".repeat(3000)
+        await Bun.write(path.join(dir, "long-line.txt"), longLine)
+      },
+    })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const read = await ReadTool.init()
+        const result = await read.execute({ filePath: path.join(tmp.path, "long-line.txt") }, ctx)
+        expect(result.output).toContain("...")
+        expect(result.output.length).toBeLessThan(3000)
+      },
+    })
+  })
+
+  test("image files set truncated to false", async () => {
+    await using tmp = await tmpdir({
+      init: async (dir) => {
+        // 1x1 red PNG
+        const png = Buffer.from(
+          "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8DwHwAFBQIAX8jx0gAAAABJRU5ErkJggg==",
+          "base64",
+        )
+        await Bun.write(path.join(dir, "image.png"), png)
+      },
+    })
+    await Instance.provide({
+      directory: tmp.path,
+      fn: async () => {
+        const read = await ReadTool.init()
+        const result = await read.execute({ filePath: path.join(tmp.path, "image.png") }, ctx)
+        expect(result.metadata.truncated).toBe(false)
+        expect(result.attachments).toBeDefined()
+        expect(result.attachments?.length).toBe(1)
+      },
+    })
+  })
+})

packages/opencode/test/tool/truncation.test.ts

@@ -0,0 +1,159 @@
+import { describe, test, expect, afterAll } from "bun:test"
+import { Truncate } from "../../src/tool/truncation"
+import { Identifier } from "../../src/id/id"
+import fs from "fs/promises"
+import path from "path"
+
+const FIXTURES_DIR = path.join(import.meta.dir, "fixtures")
+
+describe("Truncate", () => {
+  describe("output", () => {
+    test("truncates large json file by bytes", async () => {
+      const content = await Bun.file(path.join(FIXTURES_DIR, "models-api.json")).text()
+      const result = await Truncate.output(content)
+
+      expect(result.truncated).toBe(true)
+      expect(result.content).toContain("truncated...")
+      if (result.truncated) expect(result.outputPath).toBeDefined()
+    })
+
+    test("returns content unchanged when under limits", async () => {
+      const content = "line1\nline2\nline3"
+      const result = await Truncate.output(content)
+
+      expect(result.truncated).toBe(false)
+      expect(result.content).toBe(content)
+    })
+
+    test("truncates by line count", async () => {
+      const lines = Array.from({ length: 100 }, (_, i) => `line${i}`).join("\n")
+      const result = await Truncate.output(lines, { maxLines: 10 })
+
+      expect(result.truncated).toBe(true)
+      expect(result.content).toContain("...90 lines truncated...")
+    })
+
+    test("truncates by byte count", async () => {
+      const content = "a".repeat(1000)
+      const result = await Truncate.output(content, { maxBytes: 100 })
+
+      expect(result.truncated).toBe(true)
+      expect(result.content).toContain("truncated...")
+    })
+
+    test("truncates from head by default", async () => {
+      const lines = Array.from({ length: 10 }, (_, i) => `line${i}`).join("\n")
+      const result = await Truncate.output(lines, { maxLines: 3 })
+
+      expect(result.truncated).toBe(true)
+      expect(result.content).toContain("line0")
+      expect(result.content).toContain("line1")
+      expect(result.content).toContain("line2")
+      expect(result.content).not.toContain("line9")
+    })
+
+    test("truncates from tail when direction is tail", async () => {
+      const lines = Array.from({ length: 10 }, (_, i) => `line${i}`).join("\n")
+      const result = await Truncate.output(lines, { maxLines: 3, direction: "tail" })
+
+      expect(result.truncated).toBe(true)
+      expect(result.content).toContain("line7")
+      expect(result.content).toContain("line8")
+      expect(result.content).toContain("line9")
+      expect(result.content).not.toContain("line0")
+    })
+
+    test("uses default MAX_LINES and MAX_BYTES", () => {
+      expect(Truncate.MAX_LINES).toBe(2000)
+      expect(Truncate.MAX_BYTES).toBe(50 * 1024)
+    })
+
+    test("large single-line file truncates with byte message", async () => {
+      const content = await Bun.file(path.join(FIXTURES_DIR, "models-api.json")).text()
+      const result = await Truncate.output(content)
+
+      expect(result.truncated).toBe(true)
+      expect(result.content).toContain("bytes truncated...")
+      expect(Buffer.byteLength(content, "utf-8")).toBeGreaterThan(Truncate.MAX_BYTES)
+    })
+
+    test("writes full output to file when truncated", async () => {
+      const lines = Array.from({ length: 100 }, (_, i) => `line${i}`).join("\n")
+      const result = await Truncate.output(lines, { maxLines: 10 })
+
+      expect(result.truncated).toBe(true)
+      expect(result.content).toContain("The tool call succeeded but the output was truncated")
+      expect(result.content).toContain("Grep")
+      if (!result.truncated) throw new Error("expected truncated")
+      expect(result.outputPath).toBeDefined()
+      expect(result.outputPath).toContain("tool_")
+
+      const written = await Bun.file(result.outputPath).text()
+      expect(written).toBe(lines)
+    })
+
+    test("suggests Task tool when agent has task permission", async () => {
+      const lines = Array.from({ length: 100 }, (_, i) => `line${i}`).join("\n")
+      const agent = { permission: [{ permission: "task", pattern: "*", action: "allow" as const }] }
+      const result = await Truncate.output(lines, { maxLines: 10 }, agent as any)
+
+      expect(result.truncated).toBe(true)
+      expect(result.content).toContain("Grep")
+      expect(result.content).toContain("Task tool")
+    })
+
+    test("omits Task tool hint when agent lacks task permission", async () => {
+      const lines = Array.from({ length: 100 }, (_, i) => `line${i}`).join("\n")
+      const agent = { permission: [{ permission: "task", pattern: "*", action: "deny" as const }] }
+      const result = await Truncate.output(lines, { maxLines: 10 }, agent as any)
+
+      expect(result.truncated).toBe(true)
+      expect(result.content).toContain("Grep")
+      expect(result.content).not.toContain("Task tool")
+    })
+
+    test("does not write file when not truncated", async () => {
+      const content = "short content"
+      const result = await Truncate.output(content)
+
+      expect(result.truncated).toBe(false)
+      if (result.truncated) throw new Error("expected not truncated")
+      expect("outputPath" in result).toBe(false)
+    })
+  })
+
+  describe("cleanup", () => {
+    const DAY_MS = 24 * 60 * 60 * 1000
+    let oldFile: string
+    let recentFile: string
+
+    afterAll(async () => {
+      await fs.unlink(oldFile).catch(() => {})
+      await fs.unlink(recentFile).catch(() => {})
+    })
+
+    test("deletes files older than 7 days and preserves recent files", async () => {
+      await fs.mkdir(Truncate.DIR, { recursive: true })
+
+      // Create an old file (10 days ago)
+      const oldTimestamp = Date.now() - 10 * DAY_MS
+      const oldId = Identifier.create("tool", false, oldTimestamp)
+      oldFile = path.join(Truncate.DIR, oldId)
+      await Bun.write(Bun.file(oldFile), "old content")
+
+      // Create a recent file (3 days ago)
+      const recentTimestamp = Date.now() - 3 * DAY_MS
+      const recentId = Identifier.create("tool", false, recentTimestamp)
+      recentFile = path.join(Truncate.DIR, recentId)
+      await Bun.write(Bun.file(recentFile), "recent content")
+
+      await Truncate.cleanup()
+
+      // Old file should be deleted
+      expect(await Bun.file(oldFile).exists()).toBe(false)
+
+      // Recent file should still exist
+      expect(await Bun.file(recentFile).exists()).toBe(true)
+    })
+  })
+})