A stall-kill (or any crash) of mempalace-mcp was a permanent latch:
available flipped off and stayed off until pi restart. Now the next tool
call transparently respawns the server and retries.
- ensureAlive(): bounded respawn with capped exponential backoff
(MEMPALACE_MCP_MAX_RESPAWNS, default 2; MEMPALACE_MCP_RESPAWN_BACKOFF_MS,
default 1000). Respawn budget resets on any successful JSON-RPC response,
so a recovered server regains full patience while a persistently-broken
one hits the cap and stays down (no hot-loop).
- Init timeout default raised 120000 -> 300000 (scoped to init only): a
genuine virtiofs cold-open shouldn't be killed mid-progress only to
respawn and re-pay the same cost. Per-call timeout stays 60000.
- Concurrency hardening: generation counter so a late exit from a killed
old process can't tear down a fresh respawn; explicit healthy flag
replaces racy proc!=null liveness check.
- README: document self-heal, new env vars, and why generous-init +
bounded-respawn compose rather than overlap.
A wedged mempalace-mcp (classically an OrbStack virtiofs cold-open of a
large chroma.sqlite3 / HNSW load) left the awaiting JSON-RPC promise
pending forever, freezing the pi TUI uninterruptibly: ESC cancels the
LLM stream, not a pending tool execute().
The JSON-RPC client now arms a per-request timer. On expiry it rejects
the request AND kills the stalled child (SIGTERM->SIGKILL), so pi gets
an error instead of hanging; the extension flips available=false so
later calls fail fast (restart pi to retry). Per-REQUEST, not
per-process: the long-lived server only dies on a genuine stall.
Knobs: MEMPALACE_MCP_TIMEOUT_MS (default 60000),
MEMPALACE_MCP_INIT_TIMEOUT_MS (default 120000), 0 = disable.
This supersedes the planned standalone stdio-watchdog shim: the
extension already owns request/response correlation, so a separate
framing-reparsing shim is unnecessary.
Pi moved to its new home at earendil-works on 2026-05-07
(https://pi.dev/news/2026/5/7/pi-has-a-new-home).
Sweep:
- extensions/pi/mempalace.ts: 'import type { ExtensionAPI } from
"@mariozechner/pi-coding-agent"' -> @earendil-works/pi-coding-agent.
- README and extensions/pi/README: github.com/mariozechner/pi-coding-agent
URL refs -> github.com/earendil-works/pi.
- install.sh: same URL substitution in the user-facing pointer line.
Brew install references (`brew install pi-coding-agent`) left as-is:
formula still works at 0.73.1, tap update tracked upstream at
earendil-works/pi#2755.
The pi coding-agent extension at ~/.pi/agent/extensions/mempalace.ts was
living only on tor-ms22, including hand-edited fixes (Type.Unsafe
schema-passthrough for MCP tool parameters). One disk wipe away from
losing it, and no way to reproduce the install on a new machine.
- extensions/pi/mempalace.ts: canonical copy (matches tor-ms22 byte-for-byte)
- extensions/pi/README.md: what it does, the schema-passthrough gotcha,
debugging knobs
- install.sh: new install_pi_extension step — gated on ~/.pi/agent/extensions/
existing, backs up any real file in the way, idempotent re-runs, mirror
block in uninstall. Works on macOS and Linux (plain ln -s, readlink -f).
- README.md: mention extensions/pi/ in the repo-contents list and in the
Setup section
Verified on tor-ms22: install (backs up existing real file) → uninstall
(removes symlink) → reinstall (clean symlink). Re-runs are no-ops.
pi
joakimp