fix: increase output limits for truncating collector (#575)

This Pull Request addresses an issue where the output of commands
executed in the raw-exec utility was being truncated due to restrictive
limits on the number of lines and bytes collected. The truncation caused
the message [Output truncated: too many lines or bytes] to appear when
processing large outputs, which could hinder the functionality of the
CLI.

Changes Made

Increased the maximum output limits in the
[createTruncatingCollector](https://github.com/openai/codex/pull/575)
utility:
Bytes: Increased from 10 KB to 100 KB.
Lines: Increased from 256 lines to 1024 lines.
Installed the @types/node package to resolve missing type definitions
for [NodeJS](https://github.com/openai/codex/pull/575) and
[Buffer](https://github.com/openai/codex/pull/575).
Verified and fixed any related errors in the
[createTruncatingCollector](https://github.com/openai/codex/pull/575)
implementation.

Issue Solved: 

This PR ensures that larger outputs can be processed without truncation,
improving the usability of the CLI for commands that generate extensive
output. https://github.com/openai/codex/issues/509

---------

Co-authored-by: Michael Bolin <bolinfest@gmail.com>

codex-cli/src/utils/agent/exec.ts

@@ -1,3 +1,4 @@
+import type { AppConfig } from "../config.js";
 import type { ExecInput, ExecResult } from "./sandbox/interface.js";
 import type { SpawnOptions } from "child_process";
 import type { ParseEntry } from "shell-quote";
@@ -41,6 +42,7 @@ export function exec(
     additionalWritableRoots,
   }: ExecInput & { additionalWritableRoots: ReadonlyArray<string> },
   sandbox: SandboxType,
+  config: AppConfig,
   abortSignal?: AbortSignal,
 ): Promise<ExecResult> {
   const opts: SpawnOptions = {
@@ -52,7 +54,7 @@ export function exec(
   switch (sandbox) {
     case SandboxType.NONE: {
       // SandboxType.NONE uses the raw exec implementation.
-      return rawExec(cmd, opts, abortSignal);
+      return rawExec(cmd, opts, config, abortSignal);
     }
     case SandboxType.MACOS_SEATBELT: {
       // Merge default writable roots with any user-specified ones.
@@ -61,10 +63,16 @@ export function exec(
         os.tmpdir(),
         ...additionalWritableRoots,
       ];
-      return execWithSeatbelt(cmd, opts, writableRoots, abortSignal);
+      return execWithSeatbelt(cmd, opts, writableRoots, config, abortSignal);
     }
     case SandboxType.LINUX_LANDLOCK: {
-      return execWithLandlock(cmd, opts, additionalWritableRoots, abortSignal);
+      return execWithLandlock(
+        cmd,
+        opts,
+        additionalWritableRoots,
+        config,
+        abortSignal,
+      );
     }
   }
 }

codex-cli/src/utils/agent/handle-exec-command.ts

@@ -94,6 +94,7 @@ export async function handleExecCommand(
       /* applyPatch */ undefined,
       /* runInSandbox */ false,
       additionalWritableRoots,
+      config,
       abortSignal,
     ).then(convertSummaryToResult);
   }
@@ -142,6 +143,7 @@ export async function handleExecCommand(
     applyPatch,
     runInSandbox,
     additionalWritableRoots,
+    config,
     abortSignal,
   );
   // If the operation was aborted in the meantime, propagate the cancellation
@@ -179,6 +181,7 @@ export async function handleExecCommand(
         applyPatch,
         false,
         additionalWritableRoots,
+        config,
         abortSignal,
       );
       return convertSummaryToResult(summary);
@@ -213,6 +216,7 @@ async function execCommand(
   applyPatchCommand: ApplyPatchCommand | undefined,
   runInSandbox: boolean,
   additionalWritableRoots: ReadonlyArray<string>,
+  config: AppConfig,
   abortSignal?: AbortSignal,
 ): Promise<ExecCommandSummary> {
   let { workdir } = execInput;
@@ -252,6 +256,7 @@ async function execCommand(
       : await exec(
           { ...execInput, additionalWritableRoots },
           await getSandbox(runInSandbox),
+          config,
           abortSignal,
         );
   const duration = Date.now() - start;

codex-cli/src/utils/agent/sandbox/create-truncating-collector.ts

@@ -1,7 +1,6 @@
 // Maximum output cap: either MAX_OUTPUT_LINES lines or MAX_OUTPUT_BYTES bytes,
 // whichever limit is reached first.
-const MAX_OUTPUT_BYTES = 1024 * 10; // 10 KB
-const MAX_OUTPUT_LINES = 256;
+import { DEFAULT_SHELL_MAX_BYTES, DEFAULT_SHELL_MAX_LINES } from "../../config";
 
 /**
  * Creates a collector that accumulates data Buffers from a stream up to
@@ -10,8 +9,8 @@ const MAX_OUTPUT_LINES = 256;
  */
 export function createTruncatingCollector(
   stream: NodeJS.ReadableStream,
-  byteLimit: number = MAX_OUTPUT_BYTES,
-  lineLimit: number = MAX_OUTPUT_LINES,
+  byteLimit: number = DEFAULT_SHELL_MAX_BYTES,
+  lineLimit: number = DEFAULT_SHELL_MAX_LINES,
 ): {
   getString: () => string;
   hit: boolean;

codex-cli/src/utils/agent/sandbox/landlock.ts

@@ -1,4 +1,5 @@
 import type { ExecResult } from "./interface.js";
+import type { AppConfig } from "../../config.js";
 import type { SpawnOptions } from "child_process";
 
 import { exec } from "./raw-exec.js";
@@ -19,6 +20,7 @@ export async function execWithLandlock(
   cmd: Array<string>,
   opts: SpawnOptions,
   userProvidedWritableRoots: ReadonlyArray<string>,
+  config: AppConfig,
   abortSignal?: AbortSignal,
 ): Promise<ExecResult> {
   const sandboxExecutable = await getSandboxExecutable();
@@ -44,7 +46,7 @@ export async function execWithLandlock(
     ...cmd,
   ];
 
-  return exec(fullCommand, opts, abortSignal);
+  return exec(fullCommand, opts, config, abortSignal);
 }
 
 /**

codex-cli/src/utils/agent/sandbox/macos-seatbelt.ts

@@ -1,4 +1,5 @@
 import type { ExecResult } from "./interface.js";
+import type { AppConfig } from "../../config.js";
 import type { SpawnOptions } from "child_process";
 
 import { exec } from "./raw-exec.js";
@@ -24,6 +25,7 @@ export function execWithSeatbelt(
   cmd: Array<string>,
   opts: SpawnOptions,
   writableRoots: ReadonlyArray<string>,
+  config: AppConfig,
   abortSignal?: AbortSignal,
 ): Promise<ExecResult> {
   let scopedWritePolicy: string;
@@ -72,7 +74,7 @@ export function execWithSeatbelt(
     "--",
     ...cmd,
   ];
-  return exec(fullCommand, opts, abortSignal);
+  return exec(fullCommand, opts, config, abortSignal);
 }
 
 const READ_ONLY_SEATBELT_POLICY = `

codex-cli/src/utils/agent/sandbox/raw-exec.ts

@@ -1,4 +1,5 @@
 import type { ExecResult } from "./interface";
+import type { AppConfig } from "../../config";
 import type {
   ChildProcess,
   SpawnOptions,
@@ -20,6 +21,7 @@ import * as os from "os";
 export function exec(
   command: Array<string>,
   options: SpawnOptions,
+  config: AppConfig,
   abortSignal?: AbortSignal,
 ): Promise<ExecResult> {
   // Adapt command for the current platform (e.g., convert 'ls' to 'dir' on Windows)
@@ -142,9 +144,21 @@ export function exec(
   // ExecResult object so the rest of the agent loop can carry on gracefully.
 
   return new Promise<ExecResult>((resolve) => {
+    // Get shell output limits from config if available
+    const maxBytes = config?.tools?.shell?.maxBytes;
+    const maxLines = config?.tools?.shell?.maxLines;
+
     // Collect stdout and stderr up to configured limits.
-    const stdoutCollector = createTruncatingCollector(child.stdout!);
-    const stderrCollector = createTruncatingCollector(child.stderr!);
+    const stdoutCollector = createTruncatingCollector(
+      child.stdout!,
+      maxBytes,
+      maxLines,
+    );
+    const stderrCollector = createTruncatingCollector(
+      child.stderr!,
+      maxBytes,
+      maxLines,
+    );
 
     child.on("exit", (code, signal) => {
       const stdout = stdoutCollector.getString();

codex-cli/src/utils/config.ts

@@ -48,6 +48,10 @@ export const DEFAULT_FULL_CONTEXT_MODEL = "gpt-4.1";
 export const DEFAULT_APPROVAL_MODE = AutoApprovalMode.SUGGEST;
 export const DEFAULT_INSTRUCTIONS = "";
 
+// Default shell output limits
+export const DEFAULT_SHELL_MAX_BYTES = 1024 * 10; // 10 KB
+export const DEFAULT_SHELL_MAX_LINES = 256;
+
 export const CONFIG_DIR = join(homedir(), ".codex");
 export const CONFIG_JSON_FILEPATH = join(CONFIG_DIR, "config.json");
 export const CONFIG_YAML_FILEPATH = join(CONFIG_DIR, "config.yaml");
@@ -145,6 +149,12 @@ export type StoredConfig = {
     saveHistory?: boolean;
     sensitivePatterns?: Array<string>;
   };
+  tools?: {
+    shell?: {
+      maxBytes?: number;
+      maxLines?: number;
+    };
+  };
   /** User-defined safe commands */
   safeCommands?: Array<string>;
   reasoningEffort?: ReasoningEffort;
@@ -186,6 +196,12 @@ export type AppConfig = {
     saveHistory: boolean;
     sensitivePatterns: Array<string>;
   };
+  tools?: {
+    shell?: {
+      maxBytes: number;
+      maxLines: number;
+    };
+  };
 };
 
 // Formatting (quiet mode-only).
@@ -388,6 +404,14 @@ export const loadConfig = (
     instructions: combinedInstructions,
     notify: storedConfig.notify === true,
     approvalMode: storedConfig.approvalMode,
+    tools: {
+      shell: {
+        maxBytes:
+          storedConfig.tools?.shell?.maxBytes ?? DEFAULT_SHELL_MAX_BYTES,
+        maxLines:
+          storedConfig.tools?.shell?.maxLines ?? DEFAULT_SHELL_MAX_LINES,
+      },
+    },
     disableResponseStorage: storedConfig.disableResponseStorage === true,
     reasoningEffort: storedConfig.reasoningEffort,
   };
@@ -517,6 +541,18 @@ export const saveConfig = (
     };
   }
 
+  // Add tools settings if they exist
+  if (config.tools) {
+    configToSave.tools = {
+      shell: config.tools.shell
+        ? {
+            maxBytes: config.tools.shell.maxBytes,
+            maxLines: config.tools.shell.maxLines,
+          }
+        : undefined,
+    };
+  }
+
   if (ext === ".yaml" || ext === ".yml") {
     writeFileSync(targetPath, dumpYaml(configToSave), "utf-8");
   } else {

codex-cli/tests/cancel-exec.test.ts

@@ -1,5 +1,6 @@
 import { exec as rawExec } from "../src/utils/agent/sandbox/raw-exec.js";
 import { describe, it, expect } from "vitest";
+import type { AppConfig } from "src/utils/config.js";
 
 // Import the low‑level exec implementation so we can verify that AbortSignal
 // correctly terminates a spawned process. We bypass the higher‑level wrappers
@@ -12,9 +13,13 @@ describe("exec cancellation", () => {
     // Spawn a node process that would normally run for 5 seconds before
     // printing anything. We should abort long before that happens.
     const cmd = ["node", "-e", "setTimeout(() => console.log('late'), 5000);"];
-
+    const config: AppConfig = {
+      model: "test-model",
+      instructions: "test-instructions",
+    };
     const start = Date.now();
-    const promise = rawExec(cmd, {}, abortController.signal);
+
+    const promise = rawExec(cmd, {}, config, abortController.signal);
 
     // Abort almost immediately.
     abortController.abort();
@@ -36,9 +41,14 @@ describe("exec cancellation", () => {
   it("allows the process to finish when not aborted", async () => {
     const abortController = new AbortController();
 
+    const config: AppConfig = {
+      model: "test-model",
+      instructions: "test-instructions",
+    };
+
     const cmd = ["node", "-e", "console.log('finished')"];
 
-    const result = await rawExec(cmd, {}, abortController.signal);
+    const result = await rawExec(cmd, {}, config, abortController.signal);
 
     expect(result.exitCode).toBe(0);
     expect(result.stdout.trim()).toBe("finished");

codex-cli/tests/config.test.tsx

@@ -1,6 +1,11 @@
 import type * as fsType from "fs";
 
-import { loadConfig, saveConfig } from "../src/utils/config.js"; // parent import first
+import {
+  loadConfig,
+  saveConfig,
+  DEFAULT_SHELL_MAX_BYTES,
+  DEFAULT_SHELL_MAX_LINES,
+} from "../src/utils/config.js";
 import { AutoApprovalMode } from "../src/utils/auto-approval-mode.js";
 import { tmpdir } from "os";
 import { join } from "path";
@@ -275,3 +280,84 @@ test("handles empty user instructions when saving with project doc separator", (
   });
   expect(loadedConfig.instructions).toBe("");
 });
+
+test("loads default shell config when not specified", () => {
+  // Setup config without shell settings
+  memfs[testConfigPath] = JSON.stringify(
+    {
+      model: "mymodel",
+    },
+    null,
+    2,
+  );
+  memfs[testInstructionsPath] = "test instructions";
+
+  // Load config and verify default shell settings
+  const loadedConfig = loadConfig(testConfigPath, testInstructionsPath, {
+    disableProjectDoc: true,
+  });
+
+  // Check shell settings were loaded with defaults
+  expect(loadedConfig.tools).toBeDefined();
+  expect(loadedConfig.tools?.shell).toBeDefined();
+  expect(loadedConfig.tools?.shell?.maxBytes).toBe(DEFAULT_SHELL_MAX_BYTES);
+  expect(loadedConfig.tools?.shell?.maxLines).toBe(DEFAULT_SHELL_MAX_LINES);
+});
+
+test("loads and saves custom shell config", () => {
+  // Setup config with custom shell settings
+  const customMaxBytes = 12_410;
+  const customMaxLines = 500;
+
+  memfs[testConfigPath] = JSON.stringify(
+    {
+      model: "mymodel",
+      tools: {
+        shell: {
+          maxBytes: customMaxBytes,
+          maxLines: customMaxLines,
+        },
+      },
+    },
+    null,
+    2,
+  );
+  memfs[testInstructionsPath] = "test instructions";
+
+  // Load config and verify custom shell settings
+  const loadedConfig = loadConfig(testConfigPath, testInstructionsPath, {
+    disableProjectDoc: true,
+  });
+
+  // Check shell settings were loaded correctly
+  expect(loadedConfig.tools?.shell?.maxBytes).toBe(customMaxBytes);
+  expect(loadedConfig.tools?.shell?.maxLines).toBe(customMaxLines);
+
+  // Modify shell settings and save
+  const updatedMaxBytes = 20_000;
+  const updatedMaxLines = 1_000;
+
+  const updatedConfig = {
+    ...loadedConfig,
+    tools: {
+      shell: {
+        maxBytes: updatedMaxBytes,
+        maxLines: updatedMaxLines,
+      },
+    },
+  };
+
+  saveConfig(updatedConfig, testConfigPath, testInstructionsPath);
+
+  // Verify saved config contains updated shell settings
+  expect(memfs[testConfigPath]).toContain(`"maxBytes": ${updatedMaxBytes}`);
+  expect(memfs[testConfigPath]).toContain(`"maxLines": ${updatedMaxLines}`);
+
+  // Load again and verify updated values
+  const reloadedConfig = loadConfig(testConfigPath, testInstructionsPath, {
+    disableProjectDoc: true,
+  });
+
+  expect(reloadedConfig.tools?.shell?.maxBytes).toBe(updatedMaxBytes);
+  expect(reloadedConfig.tools?.shell?.maxLines).toBe(updatedMaxLines);
+});

codex-cli/tests/invalid-command-handling.test.ts

@@ -5,12 +5,12 @@ import { describe, it, expect, vi } from "vitest";
 // ---------------------------------------------------------------------------
 
 import { exec as rawExec } from "../src/utils/agent/sandbox/raw-exec.js";
-
+import type { AppConfig } from "../src/utils/config.js";
 describe("rawExec – invalid command handling", () => {
   it("resolves with non‑zero exit code when executable is missing", async () => {
     const cmd = ["definitely-not-a-command-1234567890"];
-
-    const result = await rawExec(cmd, {});
+    const config = { model: "any", instructions: "" } as AppConfig;
+    const result = await rawExec(cmd, {}, config);
 
     expect(result.exitCode).not.toBe(0);
     expect(result.stderr.length).toBeGreaterThan(0);

codex-cli/tests/raw-exec-process-group.test.ts

@@ -1,5 +1,6 @@
 import { describe, it, expect } from "vitest";
 import { exec as rawExec } from "../src/utils/agent/sandbox/raw-exec.js";
+import type { AppConfig } from "src/utils/config.js";
 
 // Regression test: When cancelling an in‑flight `rawExec()` the implementation
 // must terminate *all* processes that belong to the spawned command – not just
@@ -27,13 +28,17 @@ describe("rawExec – abort kills entire process group", () => {
     // Bash script: spawn `sleep 30` in background, print its PID, then wait.
     const script = "sleep 30 & pid=$!; echo $pid; wait $pid";
     const cmd = ["bash", "-c", script];
+    const config: AppConfig = {
+      model: "test-model",
+      instructions: "test-instructions",
+    };
 
     // Start a bash shell that:
     //  - spawns a background `sleep 30`
     //  - prints the PID of the `sleep`
     //  - waits for `sleep` to exit
     const { stdout, exitCode } = await (async () => {
-      const p = rawExec(cmd, {}, abortController.signal);
+      const p = rawExec(cmd, {}, config, abortController.signal);
 
       // Give Bash a tiny bit of time to start and print the PID.
       await new Promise((r) => setTimeout(r, 100));