pi-cli-mcp: Skill for Claude Code

Testing

The suite drives the real server over stdio and points it at a fake pi binary. No mocks of our own code: a test that passes against a stub of runPi would prove nothing about the protocol.

npm test                      # suite + type tests, no API access, no tokens
PI_CLI_MCP_LIVE=1 npm test    # also runs the real pi binary
npx vitest run test/x.test.ts # one file

Tests run the server from src/ through Node's TypeScript support, so they exercise the source, not a stale dist/.

Layout

file	covers
protocol.test.ts	handshake, JSON-RPC conformance, notifications, frame limits
answer.test.ts	answer selection, stop-reason handling, stats line, input validation
failure.test.ts	what a killed run reports: session id, progress, resumability, stderr scrubbing
lifecycle.test.ts	timeout, cancellation, shutdown, concurrency, leftover-process cleanup
sessions.test.ts	continuity across restarts, remembered options, the session mutex
transport.test.ts	print vs rpc, and reaching a running turn
packaging.test.ts	zero runtime dependencies, publishable file list
pi-contract.test-d.ts	types against the installed pi — see the pi-contract skill
live.test.ts	the real pi, opt-in

The fake pi

test/fixtures/fake-pi.mjs emits a pi-shaped --mode json stream and speaks the rpc command protocol. It exists for the paths a live model will not produce on demand: a bad or unknown stopReason, a settled-but-empty message, a 200k answer, a stream that is not JSON, a final event without a trailing newline, a hung process, transcript data leaking onto stderr, and a lockfile-based overlap detector that fails if the session mutex is removed.

Scenarios are chosen with FAKE_MODE; see the header comment for the list and the env switches.

Rules learned the hard way when editing it:

• Never process.exit() after writing. stdout to a pipe is async and exiting truncates it. Set process.exitCode. This bug once cut a 200k answer short and made a real test lie.
• process.exitCode does not stop execution. A branch that sets it must also return, or it falls through into the event stream — that is how the --list-models table once got polluted with agent events while substring assertions hid it.
• Scenarios that must hang set holding = true. They return as soon as their timers are armed, and the rpc path would otherwise read "the function returned" as "the turn is over" and exit — turning a timeout test into an instant clean exit.
• sh -c execs a single command, replacing its own image and dropping the tag from the command line that pgrep -f matches. Hence sleep 120; true # tag.