The legacy hook scripts `hooks/mempal_save_hook.sh` and
`hooks/mempal_precompact_hook.sh` shell out to `python3` for JSON
parsing and transcript-message counting. On macOS GUI launches of
Claude Code — `open -a`, Spotlight, the dock — the harness inherits
`PATH` from launchd (`/usr/bin:/bin:/usr/sbin:/sbin`), which may not
contain a `python3` at all, or may contain only a system Python that
lacks what the hook needs. The hook then fails silently in the
background log where users never look.
`mempalace` auto-ingest itself is unaffected — #340 switched that
path to the `mempalace` CLI entry point, which pipx/uv install on a
stable global PATH.
This PR adds a `MEMPAL_PYTHON` environment variable that users can
set to point the hook at any Python 3 interpreter. Resolution order
applied at each `python3` invocation site inside the two hooks:
1. $MEMPAL_PYTHON (if set and executable)
2. $(command -v python3) on PATH
3. bare `python3` as a last resort
The interpreter does not need `mempalace` installed in it — only the
standard-library `json` and `sys` modules. The hook's `mempalace mine`
call runs via the CLI, independent of this override.
hooks/README.md documents the macOS GUI PATH issue and the
MEMPAL_PYTHON override. tests/test_hooks_shell.py adds 3 regression
tests (Linux/macOS only, POSIX bash):
- MEMPAL_PYTHON override wins over PATH (proved via a
marker-emitting shim that proxies to the real interpreter).
- Non-executable MEMPAL_PYTHON falls back to PATH rather than
crashing on permission denied.
- Unset MEMPAL_PYTHON resolves via PATH.
`hooks_cli.py` (the Python implementation invoked via
`mempalace hook run ...`) already uses `sys.executable` and is
therefore trivially correct — no changes needed there.
Supersedes abandoned branch `fix/hook-bugs`.
Co-Authored-By: MSL <232237854+milla-jovovich@users.noreply.github.com>
The save hook and precompact hook were telling the agent to write
diary entries, add drawers, and add KG triples IN THE CHAT WINDOW.
Every line written stays in conversation history and retransmits on
every subsequent turn — ~$1/session in wasted tokens.
Fix: hooks now say "saved in background, no action needed" and use
decision: allow instead of block. The agent continues working without
interruption. All filing happens via the background pipeline.
Also updated hooks README with:
- Known limitation: hooks require session restart after install
- Updated cost section: zero tokens, background-only
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Igor Lins e Silva