Design rationale

Leading words: code is not intent, coverage map, Direct Supported Inferred Speculative Unknown.

Companion to subsystem-walkthrough. That skill is runtime. This one is the forces that produced the shape.

Copy these steps into the todo list verbatim. Skip with skip: <reason>.

1. Parse the target and the question. If vague, state your guess and proceed.
2. Code-anchor: paths, symbols, git blame / git log --follow, PR numbers, gh pr view when gh exists.
3. Coverage map of seven categories. Spawn one investigator per category that exists. Document the null; do not skip the search silently.
4. Synthesize with references/epistemics.md. Keep confidence language intact.
5. Present. If this investigation precedes a change, add Preserve / Change / Avoid / Risk.

Categories

1. Source control — git + gh. Always run.
2. Issue / ticket tracker
3. Long-form docs
4. Real-time chat
5. Infrastructure observability
6. Error / exception tracking
7. Product analytics

Discover tools from what this host actually exposes. Do not require a Cursor mcps/ directory. Inherit the host model. A missing category is a finding: "Real-time chat skipped. No matching tool available."

Skip a category only when no tool exists or it is provably irrelevant (a build-time script has no Sentry). Write the reason in Sources Consulted.

Output

The Question / The Code in Question / What We Found / What We Can Reasonably Infer / Competing Hypotheses / What We Don't Know / Sources Consulted (one line per category, including nulls) / Confidence Summary.

Sources Consulted is a 7-row list. A missing tool is a row, not an omitted heading. Do not open with "the user is wrong." Put their guess under Competing Hypotheses.

Reply contract

The synthesis above. Confidence language from epistemics is not rewritten.