pi-timeout

Stop pi from hanging on runaway bash commands. Set a max runtime in settings.json — pi kills the process tree at the cap and returns control with a timeout:<seconds> error. No more waiting forever on a stuck build or server.

What you're installing

The actual extension is a single TypeScript file:

extensions/pi-timeout.ts

pi discovers it through the pi manifest in package.json:

{ "pi": { "extensions": ["./extensions"] } }

pi loads every .ts/.js file under extensions/ with its built-in TypeScript loader — no compile step. extensions/pi-timeout.ts is a thin adapter (~30 lines): it registers a tool_call listener and delegates all real work to the pure, dependency-free modules under src/.

| File | Role | |------|------| | extensions/pi-timeout.ts | The extension pi loads. Registers the tool_call hook. Only file that imports pi. | | src/classify.ts | Classifies a command as run / safe / unknown. | | src/config.ts | Parses / validates / clamps / merges runTimeout. | | src/load-settings.ts | Reads global + project settings.json. | | src/handler.ts | Resolves the timeout and mutates the tool call input. |

So installing the package means pointing pi at this folder; the entry point it actually runs is extensions/pi-timeout.ts.

How it works

On every bash tool call the extension:

1. Loads your runTimeout settings (project settings override global).

2. Classifies the command as run, safe, or unknown (see the classification reference).

3. Resolves a timeout and injects it into the call:

   | Command class | Timeout applied | |---------------|-----------------| | run (recognized program launch) | maxSeconds, or fallbackMaxSeconds if maxSeconds is unset | | unknown (anything not recognized) | fallbackMaxSeconds | | safe (git / build / test / install / file ops) | never capped |

   A timeout the model set explicitly on the call is always respected and never overridden.

When the timeout elapses, pi kills the process tree and the tool returns a timeout:<seconds> error, so pi can react instead of hanging.

Install

Local path (development / personal use)

Add the absolute path to the package in your pi settings:

// ~/.pi/agent/settings.json
{
  "packages": ["/absolute/path/to/pi-timeout"]
}

Restart pi. The extension loads automatically.

npm or git (later)

The package is structured for publishing with no changes. Once published:

{ "packages": ["npm:@jamiefutch/pi-timeout"] }

or

{ "packages": ["git:github.com/you/pi-timeout"] }

Configure

Add a runTimeout object to ~/.pi/agent/settings.json (global) or .pi/settings.json (project). Project settings override global settings per key.

| Key | Type | Meaning | |-----|------|---------| | runTimeout.maxSeconds | positive number (seconds) | Cap for recognized run-commands. | | runTimeout.fallbackMaxSeconds | positive number (seconds) | Safety-net cap for everything non-safe — unknown commands, and run-commands when maxSeconds is unset. |

Rules:

• Units are seconds (pi's bash timeout unit).
• Values must be positive finite numbers. Values above 2147483.647 seconds (pi's bash ceiling) are clamped down. Invalid values are ignored.
• Opt-in: if neither key is set, the extension does nothing.

Examples

Simplest "never hang" mode — cap every non-safe command at 2 minutes:

{ "runTimeout": { "fallbackMaxSeconds": 120 } }

Tight cap on recognized program launches, looser net for everything else:

{ "runTimeout": { "maxSeconds": 30, "fallbackMaxSeconds": 300 } }

Project override — global sets a loose fallback; this project wants a tight cap:

// ~/.pi/agent/settings.json
{ "runTimeout": { "fallbackMaxSeconds": 300 } }

// .pi/settings.json
{ "runTimeout": { "maxSeconds": 10 } }

// Effective: maxSeconds = 10 (project), fallbackMaxSeconds = 300 (global)

Build

There is no build step to use the package. pi loads the TypeScript extension directly, so you never compile or bundle anything for pi to run it.

For development, install the dev tooling once:

npm install

Then use the checks (full test suite + strict typecheck):

npm test          # vitest run — 112 tests
npm run typecheck # tsc --noEmit — strict type check

Verify

Test that the timeout extension works using the included C# app:

cd test/csharp-hang
dotnet build -c Release
./bin/Release/net9.0/csharp-hang

With default settings (maxSeconds: 30), the 10-second sleep should complete normally. To verify the cap fires, temporarily lower maxSeconds in ~/.pi/agent/settings.json:

{ "runTimeout": { "maxSeconds": 3 } }

Then re-run — pi kills the process at 3 seconds with a timeout:3 error instead of finishing the 10-second sleep. Restore your settings after.

Run

Run it in pi (normal use)

1. Install — add the package to packages in ~/.pi/agent/settings.json (see Install).
2. Configure — set runTimeout.maxSeconds and/or runTimeout.fallbackMaxSeconds (see Configure).
3. Restart pi. The extension loads automatically and caps bash commands from then on.

Smoke test that it's active — with runTimeout.maxSeconds: 3 set, ask pi:

Run this exact bash command: sleep 30

pi should return in ~3 seconds with a timeout:3 result instead of waiting 30 seconds.

Run the test suite (development)

npm test            # run all tests once
npm run test:watch  # re-run on change

Classification reference

Commands are split on &&, ||, ;, and |, and leading wrappers (sudo, nohup, time, command, exec, env, and VAR=value assignments) are stripped before classifying. If any segment is a run-command, the whole command is treated as run; if all segments are safe, it is safe; otherwise unknown.

run — capped at maxSeconds (or fallbackMaxSeconds)

| Shape | Examples | |-------|----------| | .NET | dotnet run, dotnet bin/Debug/net8.0/App.dll, dotnet ./out/App.exe | | Node / Bun / Deno | node dist/index.js, bun app.js, bun run dist/app.js, deno run main.ts | | Rust | cargo run, cargo run --release | | Go | go run ., go run cmd/server/main.go | | Python | python main.py, python3 app.py, uv run serve.py | | Java | java -jar app.jar, java com.example.Main | | PHP / Ruby | php index.php, ruby script.rb | | npm scripts | npm start, npm run serve | | Bare executable | ./app, ./target/release/app, ../bin/run, /usr/local/bin/tool, ./app.exe |

Note: npm run <script> (including npm run build) is treated as run, because npm scripts commonly start long-lived processes. If a script is a quick build step, raise maxSeconds or have pi set an explicit timeout.

safe — never capped

• File/text ops: git, ls, cat, grep, rg, find, echo, mkdir, rm, cp, mv, touch, head, tail, wc, sort, diff, …
• Build/test/install verbs: cargo build|test|check|clippy, dotnet build|test|restore, go build|test|vet, make, cmake, mvn, gradle, npm|pnpm|yarn install|test|lint|build, pip install, brew.

unknown — capped at fallbackMaxSeconds

Anything not matched above, e.g. sleep 30, curl https://…, some-custom-tool. This is the safety net that guarantees pi never hangs on an unrecognized command (when fallbackMaxSeconds is set).

Behavior & guarantees

• Explicit timeouts win. If pi sets a timeout on a specific bash call, it is never overridden.
• Safe tooling is never capped, so long builds and test suites run to completion.
• Process tree is killed at the cap (pi's bash tool behavior), so child processes don't linger.
• No UI. The timeout surfaces as the bash tool's timeout:<seconds> error, which the model sees and typically reports.

FAQ / troubleshooting

A command I expected to be capped wasn't. It probably classified as safe. Check the reference above. If it should be capped, set fallbackMaxSeconds (covers unknown) — and if it's a tool we marked safe that you want capped, that's a rule change in src/classify.ts.

My build (npm run build) got killed. npm run <script> is classified as run. Raise maxSeconds, or have pi pass an explicit longer timeout on that call (explicit timeouts are respected).

I want to disable it temporarily. Remove the runTimeout keys (or set them to invalid values). The extension becomes inert.

Are seconds really the unit? Yes. pi's bash timeout is in seconds; this package matches it.

Development

All decision logic is pure and dependency-free under src/; only extensions/pi-timeout.ts imports pi (see What you're installing). For build and test commands see Build and Run.

License

MIT