change-impact

Change Impact

Produce an evidence-backed map of what the selected change can affect, the one or two assumptions carrying most of its safety, and a finite verification list. Do not broaden the current task, mutate during a read-only review, or turn a residual finding into successor work.

Confirm The Gate

Use this skill when the proposed or reviewed change crosses at least one material boundary:

• a public interface, wire format, shared contract, or independently deployed consumer;
• persisted state, a schema, migration, cache, or compatibility contract;
• authorization, permissions, entitlements, secrets, or another trust boundary;
• build, packaging, deployment, rollout, rollback, or release behavior; or
• three or more downstream branches whose failure modes need separate proof.

Skip it when the change is local behind an unchanged interface and focused tests cover the behavior. Do not activate it merely because a diff is large, the user requested an ordinary review, or a polished risk section would make a completed decision look safer.

Map The Reach

1. Bind the exact change and current evidence: repository, ref or worktree, relevant diff, intended behavior, and the authority granted by the user.
2. Start with the repo-declared retrieval lane that matches the evidence: use jcode for definitions, call sites, callers, and adjacent code; jdocs for authored contracts, runbooks, and reference trees; and jdata for tabular or dataset-backed impact. Use only lanes relevant to the crossed boundary. A miss clears only the named query and scope; do not sweep all lanes or connectors.
3. Trace each crossed boundary to concrete consumers. Go beyond symbol callers when behavior also travels through serialized data, configuration, generated code, lifecycle ordering, pinned dependencies, operational automation, or a different runtime or language.
4. For every plausible consumer, record the interface crossed, reachability, failure mode, supporting location or runtime evidence, and status: confirmed risk, cleared, or unproven. A search with no matches is useful cleared evidence when its scope is named.
5. Keep cleared checks visible. Do not report only alarming possibilities, and do not promote a hypothetical failure without a reachable path.