Use when the user wants to know what will break if they change something, or needs safety analysis before editing code. Examples: "Is it safe to change X?", "What depends on this?", "What will break?"

Impact Analysis with GitNexus When to Use "Is it safe to change this function?" "What will break if I modify X?" "Show me the blast radius" "Who uses this code?" Before making non trivial code changes Before committing — to understand what your changes affect Bind the repository first Impact analysis is the gate that authorizes an edit, so it must answer for the repository you are about to edit. Call list repos {} before the first tool call. With one indexed repository, use the examples below as written. With more than one, pass repo on every call: an omitted repo normally errors, but under an MCP policy with a configured default it resolves to that default silently. If you cannot tell which repository is meant, stop and ask — every result below an ambiguous identity inherits the ambiguity. list repos is paginated, so page with offset: pagination.nextOffset until hasMore is false before concluding a repository is absent. detect changes takes worktree when your changes are in a linked worktree the MCP server was not launched from. The server auto detects a worktree only when it was launched from inside one; otherwise git diff runs in the wrong checkout and reports zero changed symbols — a false clean check that carries none of the degradation flags described below. In the CLI fallbacks, repo . means the current checkout; pass the intended repository path instead when you are not standing in it. State the bound identity with your risk report: Workflow If "Index is stale" → run node .gitnexus/run.cjs analyze in terminal. If .gitnexus/run.cjs is missing, replace node .gitnexus/run.cjs with npx gitnexus in the fallback commands. Checklist Understanding Output Depth Risk Level Meaning d=1 WILL BREAK Direct callers/importers d=2 LIKELY AFFECTED Indirect dependencies d=3 MAY NEED TESTING Transitive effects Risk Assessment Affected Risk <5 symbols, few processes LOW 5 15 symbols, 2 5 processes MEDIUM 15 symbols or many processes HIGH Critical path (auth, payments) CRITICAL Zero callers found UNKNOWN UNKNOWN is not a low rung on this scale — it means the walk could not answer. An empty caller set is equally consistent with "genuinely unused" and "the callers are not resolvable by the index" (plain object property access, dynamic dispatch, cross language calls), so few callers ⇒ LOW does not apply. The result carries a riskNote saying so. Confirm with a text search before treating the symbol as safe to change or delete. risk is the edit gate: warn on HIGH/CRITICAL and stop on UNKNOWN until the uncertainty is resolved. Within single repo mode, compare File and symbol targets with local riskSharedAxes (direct/total only). Within group mode, compare only group results: their riskSharedAxes overlays resolved cross repo crossings on that local value. Never use either field to waive the edit gate. Check riskScale.unusedAxes before comparing kinds: MCP File walks omit process/module axes, while web Graph RAG expands File targets to in file symbols before enrichment. Tools impact — the primary tool for symbol blast radius. If MCP is unavailable, use node .gitnexus/run.cjs impact <symbol direction upstream repo . instead: detect changes — git diff based impact analysis. If MCP is unavailable, use node .gitnexus/run.cjs detect changes scope all repo . instead: Add repo once more than one repository is indexed, and worktree: "<abs path " when your changes are in a linked worktree the server was not launched from. partial: true (a graph query failed) or truncated: true (the changed symbol listing was capped) means the result is short of the truth, and reads like UNKNOWN above: a zero there means unseen, not unaffected. Re run it rather than tick the pre commit check. A wrong worktree zero carries neither flag and is shape identical to a genuine clean result, so confirm the checkout you edited is the one that was diffed before treating an empty change set as a passed check. Example: "What breaks if I change validateUser?" With a single indexed repository, step 0 returns total: 1 and the repo argument drops out of every call above.

gitnexus-impact-analysis