Simulation Triage

Determine what failed, why, and who can repair it. Treat supplied labels and attributions as hypotheses to check. Read {workdir}/dispatch.json for input locations. sim_run names the failed run itself; inspect its result, logs, TB, coverage and any retained waveform rather than a later canonical result. intent, requirements, design, plan and rtl provide the other evidence.

Read the material needed to resolve the question, including tool scripts when relevant. Keep canonical inputs unchanged; write diagnostics and experiments under {workdir}. Attribute causes from the evidence, including local simulation defects.

Investigate

Form a concrete hypothesis from the requirement and observed behavior. Check the implementation, stimulus, observation and expected result. A reference model must derive its expected behavior from an independent task authority; disagreement with the current plan can expose a plan defect.

Use retained waveforms when useful. Passing simulation tests normally discard their FSDB, so a coverage failure may need a focused rerun to observe the relevant behavior. Discover actual signal paths from the TB and design. For the supplied fsdbreport tool, query one signal per invocation: it retains only the last -s, and its paths are slash-form rooted at the testbench. An unmatched path can return exit code 0 with an empty report; inspect the warning before interpreting that as missing waveform data.

fsdbreport <waveform.fsdb> -s /<actual-signal-path> -bt <t0> -et <t1> -of h -o experiment/window.txt

If the existing evidence is insufficient, build a focused experiment under experiment/. Use the unchanged implementation for claims about the failure; if varying something to test a hypothesis, state what changed and what that comparison can establish. Keep commands, inputs and results. A failed attempt to reach behavior does not prove it unreachable; approval does not supply that proof either. Distinguish a technical evidence gap from an acceptance decision needing authorization.

Return the diagnosis

Submit the diagnosis object described by result.schema.json to the CLI, which validates it and writes result.json:

python3 <skill>/scripts/simtriage/__main__.py finalize --workdir {workdir} --json-stdin

<skill> is this skill's directory. Each supported finding identifies its root_cause repair stage, anchor and reason. The owner can be simulation itself. Separate independently supported causes; do not invent an owner to obtain a route. If evidence cannot settle attribution, leave findings empty and explain the missing evidence in reason. This completed diagnosis returns the unresolved decision to the caller; it does not request another identical investigation.

Finalize validates the diagnosis structure and preserves experiment/; it does not prove the reasoning. Return STATUS: DONE when the diagnosis is written, including an explicit unresolved attribution. Return STATUS: BLOCKED <cause> if you could not produce it. Do not invoke kernel state transitions or edit another stage's outputs.