The shipped subagent example could say a child was done while it was still working, lose the useful part of process failures, and return a normal-looking tool result when the delegated work had actually failed. Single and chain output could also exceed the normal tool limit. This also adds a dedicated regression suite covering progress state, cancellation, process failures, output limits, cwd-based agent selection, and persisted tool-result error state. After this change: - queued, running, completed, failed, and aborted work stay distinct throughout the run; - interrupting the parent run preserves partial child results, stops queued work from starting, and escalates when a child ignores SIGTERM; - signal exits, spawn failures, provider errors, stderr, and assistant output remain visible instead of collapsing to `(no output)`; - failed subagents become failed tool results, so the parent model can react instead of treating them as successful calls; - single and chain results stay within the normal 50 KB / 2,000-line limit; - project agents are selected and confirmed from each task's actual working directory rather than the dispatcher's directory. ## Further potential improvements These are useful follow-ups, but they are separate product and storage decisions rather than part of the failure-handling fixes in this PR. <details> <summary>Potential follow-ups</summary> ### Keep persisted transcripts bounded Subagent tool results persist the full child message history in `details`, which can make parent session files large and slow to reload. A follow-up could compact that history or spill it to disk. ### Define an aggregate parallel-output budget Parallel mode still gives every task its own 50 KB budget. A follow-up could keep every task represented while enforcing one overall tool-result limit. ### Report child usage to the calling session Per-child token and cost usage is visible in result cards but is not added to the calling session's totals. ### Isolate malformed agent definitions One malformed YAML agent can still break discovery for every valid agent in the same directory. ### Limit subagent recursion A nesting limit would prevent accidental process and paid-request multiplication when subagents can invoke the subagent tool again. * https://github.com/earendil-works/pi/issues/8195 ### Add a configurable timeout Unattended runs would benefit from a generous opt-in timeout for children that never complete. </details> ## Related issues ### Spawn failures lose their diagnostics This directly addresses the reported case where a nonexistent child working directory produces `(no output)` instead of the actual spawn error. The regression suite includes that same reproduction. * https://github.com/earendil-works/pi/issues/8129 ### Persisted child history can bloat sessions This PR intentionally keeps full child history in tool-result details, so session compaction or spill-to-disk remains follow-up work rather than something fixed here. * https://github.com/earendil-works/pi/issues/7452 |
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| .pi | ||
| apps/p2 | ||
| nix | ||
| packages | ||
| scripts | ||
| .gitattributes | ||
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| .npmrc | ||
| AGENTS.md | ||
| biome.json | ||
| CONTRIBUTING.md | ||
| flake.lock | ||
| flake.nix | ||
| LICENSE | ||
| package-lock.json | ||
| package.json | ||
| pi-test.bat | ||
| pi-test.ps1 | ||
| pi-test.sh | ||
| README.md | ||
| SECURITY.md | ||
| test.sh | ||
| tsconfig.base.json | ||
| tsconfig.json | ||
| vitest.base.ts | ||
New issues and PRs from new contributors are auto-closed by default. Maintainers review auto-closed issues daily. See CONTRIBUTING.md.
Pi
Pi is a minimal, extensible agent harness that you can make your own.
Adapt Pi to your workflows, not the other way around. Customize Pi with extensions, skills, prompt templates, and themes. Bundle them as Pi packages and share via npm or git.
Pi ships with powerful defaults but skips features like sub-agents and plan mode. Ask Pi to build what you want, or install a package that does it your way.
Use Pi interactively, automate it in print or JSON mode, control it over RPC, or build apps with the Pi TypeScript SDK. See OpenClaw for a real-world integration.
Getting started
Install the command-line interface:
curl -fsSL https://pi.dev/install.sh | sh
On Windows:
powershell -c "irm https://pi.dev/install.ps1 | iex"
The installer pins all dependencies and updates Pi with pi update. Alternatively, install directly with npm, which does not pin transitive dependencies:
npm install -g --ignore-scripts @earendil-works/pi-coding-agent
Pi requires Node.js 22.19 or newer. The macOS, Linux, and Windows installers can install it if needed. Pi does not require dependency lifecycle scripts for a normal npm installation.
Start Pi in the directory where you want it to work:
cd /path/to/project
pi
For a built-in AI provider, run /login inside Pi to connect a subscription or API key. Then give Pi a task.
See the documentation for full setup and usage instructions, or visit pi.dev for demos.
Run with Nix
nix run github:earendil-works/pi/stable
stable points at the latest release. Install it with nix profile add github:earendil-works/pi/stable and update with nix profile upgrade pi. Use a release tag such as github:earendil-works/pi/v1.0.0 to pin a version, or github:earendil-works/pi for unreleased changes on main. Nix builds Pi from source.
Supports ARM64 and x86-64 on Linux and macOS. Use nix build . or nix run . to build or run your checkout.
Nix builds are offline, so the bundled model data comes from a pi.dev model catalog revision pinned in nix/model-catalog.json. At runtime, Pi still overlays newer catalog data from pi.dev as usual. The Nix workflow replaces the pin on main when it no longer matches the checkout, for example after a provider is added or gains a new model type. To refresh it by hand:
npm run update:model-catalog-pin
Packages
This monorepo contains the Pi CLI and its supporting libraries.
| Package | Description |
|---|---|
| @earendil-works/chord | Object runtime for apps across processes: contracts, documents, a store, links, plugins with hot reload, HTTP, workers, web and terminal clients |
| @earendil-works/pi-telemetry | Vendor-neutral telemetry contracts, reference adapter, conformance tests, and typed schemas |
| @earendil-works/pi-ai | Unified multi-provider LLM API (OpenAI, Anthropic, Google, etc.) |
| @earendil-works/pi-durable | Durable conversation, task, and document runtime |
| @earendil-works/pi-agent-core | Agent runtime with tool calling and state management |
| @earendil-works/pi-coding-agent | Interactive coding agent CLI |
| @earendil-works/pi-tui | Terminal UI library with differential rendering |
For Slack/chat automation and workflows see earendil-works/pi-chat.
Permissions & Containerization
Pi does not include a built-in permission system for restricting filesystem, process, network, or credential access. By default, it runs with the permissions of the user and process that launched it.
If you need stronger boundaries, containerize or sandbox Pi. See packages/coding-agent/docs/containerization.md for three patterns:
- Gondolin extension: keep
piand provider auth on the host while routing built-in tools and!commands into a local Linux micro-VM. - Plain Docker: run the whole
piprocess in a local container for simple isolation. - OpenShell: run the whole
piprocess in a policy-controlled sandbox.
Contributing
See CONTRIBUTING.md for contribution guidelines and AGENTS.md for project-specific rules (for both humans and agents). Longer term plans for Pi can also be found in RFCs.
Development
npm install --ignore-scripts # Install all dependencies without running lifecycle scripts
npm run build # Refresh model data, then build all packages
npm run build:offline # Rebuild using existing model data without network access
npm run check # Lint, format, and type check
./test.sh # Run tests (skips LLM-dependent tests without API keys)
./pi-test.sh # Run pi from sources (can be run from any directory)
Using local packages outside the monorepo
Build every public package into one coherent local artifact set:
npm run pack:packages -- --out .artifacts/pi-packages
This refreshes model data before building pi-ai. To avoid network access when
model data is already hydrated, pass --offline-model-data.
Then configure an external project to consume one package and resolve all of its Pi dependencies from the same artifact set. npm is the default:
node scripts/use-local-packages.mjs \
--manifest .artifacts/pi-packages/manifest.json \
--consumer ../my-project \
--package @earendil-works/pi-durable \
--package @earendil-works/pi-agent-core
cd ../my-project
npm install --ignore-scripts
For a pnpm project, point --consumer at the workspace root:
node scripts/use-local-packages.mjs \
--manifest .artifacts/pi-packages/manifest.json \
--consumer ../my-project \
--package @earendil-works/pi-agent-core \
--package-manager pnpm
cd ../my-project
pnpm install --ignore-scripts
Repeat --package for each direct dependency. The command updates the
consumer's package.json with content-addressed local file: references. It
writes transitive overrides to package.json for npm or pnpm-workspace.yaml
for pnpm. Keep the artifact directory available while installing or updating
the consumer. Re-run both commands after changing Pi source.
Building standalone binaries from release source
GitHub releases include a versioned source archive covered by the release's SHA256SUMS file. Extract it and run the same build script used for the official standalone binaries:
VERSION="<release-version>"
tar -xzf "pi-${VERSION}-source.tar.gz"
cd "pi-${VERSION}"
./scripts/build-binaries.sh --offline-model-data --platform linux-x64 --out "$PWD/out"
The archive includes release model data and native prebuilds. --offline-model-data uses that model data without refreshing provider catalogs. The script installs dependencies and builds the executable with its runtime assets; pass --skip-install if dependencies are already provided.
Supply-chain hardening
We treat npm dependency changes as reviewed code changes.
- Direct external dependencies are pinned to exact versions. Internal workspace packages remain version-ranged.
.npmrcsetssave-exact=trueandmin-release-age=2to avoid same-day dependency releases during npm resolution.package-lock.jsonis the dependency ground truth. Pre-commit blocks accidental lockfile commits unlessPI_ALLOW_LOCKFILE_CHANGE=1is set.npm run checkverifies pinned direct deps, native TypeScript import compatibility, and the generated coding-agent install lock.- The pi.dev installer installs from
packages/coding-agent/install-lock/, generated from the root lockfile, to pin transitive deps. The npm package does not pin transitive deps. - Local release smoke tests and npm publication use the same tarball packer; npm publishes the validated tarballs rather than repacking workspace directories.
- Local release installs, documented npm installs, and
pi update --selfuse--ignore-scriptswhere supported. - CI installs with
npm ci --ignore-scripts, and a scheduled GitHub workflow runsnpm audit --omit=devplusnpm audit signatures --omit=dev. - Install lock generation has an explicit allowlist for dependency lifecycle scripts; new lifecycle-script deps fail checks until reviewed.
Share your OSS coding agent sessions
If you use Pi or other coding agents for open source work, please share your sessions.
Public OSS session data helps improve coding agents with real-world tasks, tool use, failures, and fixes instead of toy benchmarks.
For the full explanation, see this post on X.
To publish sessions, use badlogic/pi-share-hf. Read its README.md for setup instructions. All you need is a Hugging Face account, the Hugging Face CLI, and pi-share-hf.
You can also watch this video, where I show how I publish my pi-mono sessions.
I regularly publish my own pi-mono work sessions here:
License
MIT