I think the preferred way is to first try mempalace binary if it can be found

Thanks for tackling this — the underlying need is real (we use uv in some setups and don't always have python on PATH, so MEMPALACE_PYTHON as an escape hatch is exactly right).

Blocker before we merge: the two Windows checkboxes in the test plan are unchecked, and Windows is the primary platform this fix targets. Specifically the scenarios that would confirm the fix works:

1. Git Bash on Windows 11 with no python3 on PATH but python present — confirm find_python falls back to python and the save hook's inline python -c JSON parsing actually runs.
2. MEMPALACE_PYTHON override — set it to an absolute path like C:\Users\you\.local\pipx\venvs\mempalace\Scripts\python.exe and verify the background mempalace mine call picks it up.
3. Python 3.14 guard — launch the MCP server under 3.14 and confirm the JSON-RPC error lands on stdout without the pydantic ConfigError.

Without those, we'd be merging a Windows fix on faith. Can you run through those three and report back what you saw?

Two secondary points to consider while you're in there:

• Python 3.14 guard is future-fragile. sys.version_info >= (3, 14) becomes wrong the moment chromadb supports 3.14 — the guard will tell users to downgrade when they no longer need to. Two alternatives that age better: (a) catch the pydantic ConfigError around the chromadb import and re-raise with a better message, or (b) gate the guard on a chromadb version range (if chromadb.__version__ < "1.0" and sys.version_info >= (3, 14)). Either way the message stays useful; neither locks us out later.
• else echo "python3" in find_python silently keeps the broken default when both python3 and python are missing. It'd be friendlier to echo "" && return 1 and have the caller exit with a clear "no Python found — set MEMPALACE_PYTHON" message, since downstream $PYTHON -c calls will fail opaquely otherwise.

Context on prior art: #740 by @milla-jovovich touched the same files and was closed yesterday. The closure reasoning was narrower than your PR's scope (nohup PATH stripping in a private variant, not addressed by the public python3 -m mempalace entry point). Your PR legitimately covers a different angle — the inline python3 -c / python3 - <<PYEOF calls in the save hook bypass the module entry point and hit the python3-doesn't-exist path on Windows directly. Worth naming that distinction in the PR body so reviewers don't bounce it as a duplicate.

cc @milla-jovovich — you closed #740 with a clear model of the hook failure modes; wanted to make sure your perspective is folded in before this lands.

Thanks for tackling this — the underlying need is real (we use uv in some setups and don't always have python on PATH, so MEMPALACE_PYTHON as an escape hatch is exactly right).

Blocker before we merge: the two Windows checkboxes in the test plan are unchecked, and Windows is the primary platform this fix targets. Specifically the scenarios that would confirm the fix works:

1. Git Bash on Windows 11 with no python3 on PATH but python present — confirm find_python falls back to python and the save hook's inline python -c JSON parsing actually runs.
2. MEMPALACE_PYTHON override — set it to an absolute path like C:\Users\you\.local\pipx\venvs\mempalace\Scripts\python.exe and verify the background mempalace mine call picks it up.
3. Python 3.14 guard — launch the MCP server under 3.14 and confirm the JSON-RPC error lands on stdout without the pydantic ConfigError.

Without those, we'd be merging a Windows fix on faith. Can you run through those three and report back what you saw?

Two secondary points to consider while you're in there:

• Python 3.14 guard is future-fragile. sys.version_info >= (3, 14) becomes wrong the moment chromadb supports 3.14 — the guard will tell users to downgrade when they no longer need to. Two alternatives that age better: (a) catch the pydantic ConfigError around the chromadb import and re-raise with a better message, or (b) gate the guard on a chromadb version range (if chromadb.__version__ < "1.0" and sys.version_info >= (3, 14)). Either way the message stays useful; neither locks us out later.
• else echo "python3" in find_python silently keeps the broken default when both python3 and python are missing. It'd be friendlier to echo "" && return 1 and have the caller exit with a clear "no Python found — set MEMPALACE_PYTHON" message, since downstream $PYTHON -c calls will fail opaquely otherwise.

Context on prior art: #740 by @milla-jovovich touched the same files and was closed yesterday. The closure reasoning was narrower than your PR's scope (nohup PATH stripping in a private variant, not addressed by the public python3 -m mempalace entry point). Your PR legitimately covers a different angle — the inline python3 -c / python3 - <<PYEOF calls in the save hook bypass the module entry point and hit the python3-doesn't-exist path on Windows directly. Worth naming that distinction in the PR body so reviewers don't bounce it as a duplicate.

cc @milla-jovovich — you closed #740 with a clear model of the hook failure modes; wanted to make sure your perspective is folded in before this lands.

thanks for the review.
For Windows machine, I'm afraid to let you know that I don't have any windows machine to test but anyone with Window machine is welcome and would be glad to continue if there's anything broke.