tony 00-scan
Profile, detect, hypothesize. This phase only reads the suite and only writes JSON to the memory directory. No test is edited here.
$ARGUMENTS may scope the run to a path or marker, set --runs=N (baseline
sample count, default 5), --force to ignore the idempotency token, and
--memory-dir to override the memory location.
Step 1: Preflight
Detect preferred tools (rg/ag/fd/jq/uv/uvx) and read the project's
own test command from AGENTS.md, CLAUDE.md, justfile, tox.ini, or
pyproject.toml. Do not hardcode a runner. Record the resolved command; every
later phase reuses it. Substitute it wherever this file writes pytest.
Step 2: Resolve memory and check idempotency
Resolve the memory directory per references/memory-schema.md
(repo-root .pytest-optimizer/, gitignored; XDG fallback). Compute the
idempotency token (git HEAD + collection node-ids + pytest/plugin versions +
environment fingerprint). If state.json shows scan completed with an unchanged
token and
hypotheses.json exists, report "already scanned" and stop — unless --force.
Step 3: Detect capabilities
Probe the installed pytest and plugins against
references/version-matrix.md. Write
capabilities.json. Use only available features below; fall back as the matrix
directs (e.g. no --durations-min pre-6.1 → post-filter rows).
Step 4: Establish the baseline and noise band
Run the suite serially, cache disabled, --runs times, and record total
wall-time each run:
pytest -p no:cacheprovider -p no:randomly -q
Compute the median and MAD of the per-run totals; set the noise band
(median + k·MAD, default k = 3) and the ~50ms trust floor. Write the env
fingerprint, versions, capabilities, and the band to baseline.json. See
references/durations-parsing.md.
Step 5: Profile slowest tests and fixtures
Capture per-phase timings and bucket rows by the when token (call vs
setup/teardown), de-duplicating by (nodeid, when):
pytest --durations=0 --durations-min=0.005 -p no:cacheprovider -p no:randomly
Rank slowest test bodies (call, H01) and slowest fixture
setup/teardown (setup/teardown, H02). For shared higher-scope fixtures whose
cost is billed to one nodeid (H03), note the attribution; offer the opt-in timing
plugin if precise per-fixture cost is needed. Persist the timings to
baseline.json.
Step 6: Run the static detectors
Work through references/heuristic-catalog.md, using
references/fixture-analysis.md for the fixture recipes and
references/parametrize-convention.md for the typing/
parametrize gaps:
- Fixtures: unused (H08/H09/H41), mis-scoped (H10/H13), duplicate (H11), autouse (H12/H15), mark-on-fixture (H43), empty conftest (H42).
- Collection/capability errors (H14/H22/H44).
- Typing and parametrize gaps (H26–H32).
- I/O, sleep, markers, timeouts (H15/H33/H37/H39/H40).
- Recomputation and duplication (H24/H25/H34/H35/H36/H38).
Apply the getfixturevalue guard (H09) before proposing any fixture deletion.
Step 7: Emit hypotheses
Write hypotheses.json: one entry per firing detector, each tagged with its
heuristic id, the goal(s) it addresses, the raw evidence, and prior risk/effort.
Do not estimate impact here — 01-benchmark measures it. Update state.json
(phase=scan, completed.scan=true, token).
Step 8: Report
Emit the 00-scan sections from
references/output-contract.md: a hero block, then
## Environment, ## Baseline, ## Slowest tests, ## Slowest fixtures,
## Hypotheses. Close with an ask-user-choice panel offering to benchmark the
hypotheses, narrow scope, or stop.
Portability notes
ask-user-choice— present the listed options and wait for the user to pick one. Hosts with a structured multiple-choice tool (Claude Code'sAskUserQuestion) should use it; otherwise print a numbered list and wait for a numbered reply. Never proceed on an assumed answer.$ARGUMENTS— the text the user passed when invoking this skill. If your host does not substitute it, read it as the user's request in the current turn, and ask when there is none.- Bundled files — every relative path in this skill points at a file shipped inside this skill directory. Read them from here, not from the host's plugin tree.