U3 of the Claude Desktop .mcpb bundle plan.
- internal/engine/run.go invokes python3 with the cached last30days.py,
forwards os.Environ() so MCPB user_config env-injection reaches the
engine, sets PYTHONPATH so the lib/ imports resolve, and surfaces
three distinct error shapes (missing interpreter with install URL,
non-zero exit with stderr, timeout). RunOptions.PythonPath lets tests
inject a stub without manipulating PATH.
- internal/engine/run_test.go drives a shell-script stub interpreter
through happy path, env forwarding, PYTHONPATH, non-zero exit with
stderr surfacing, timeout, missing python3 (empty PATH), missing
last30days.py, empty CacheDir, and timeout-env-override parsing.
- internal/tools/research.go registers a single research tool whose
schema mirrors /last30days <topic> (required topic, optional emit
enum, optional save bool). Validation failures surface as MCP
tool errors so Claude sees structured failures instead of transport
faults; engine extract or run errors fold engine stderr into the
message so users can diagnose without leaving Desktop.
- internal/tools/research_test.go covers requireString, emitArgument,
boolArgument, handler-level validation routing, and formatRunError.
- cmd/last30days-pp-mcp/main.go wires NewMCPServer + tools.Register +
ServeStdio. main.Version is ldflags-stamped at build time and
namespaces the per-user cache. mcp-go pinned at v0.54.0.
Smoke check: ./build/last30days-pp-mcp answers tools/list with the
research tool plus full schema and read-only/open-world annotations.
go test ./... passes across engine + tools (32 cases).
Matt Van Horn
35f12cb9ea