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impact

impact

github.com/terrylicaDevelopment279 installsUpdated 1d ago
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About impact

impact is a GitNexus CLI skill for analyzing how changes to a symbol may affect callers, processes, and tests. It uses index status, dependency direction, and test coverage to inform change-risk assessment; the README explicitly says no MCP server exists.

Key features

  1. 01Check index status and reindex if needed
  2. 02Analyze upstream callers of a symbol
  3. 03Inspect downstream dependencies
  4. 04Find related test coverage
  5. 05Structure impact and risk reports

Use cases

  1. 01Assess blast radius before changing a function
  2. 02Evaluate whether modifying a symbol is safe
  3. 03Review processes and tests involving a symbol

MCP support

The README explicitly states that this is CLI-only and no MCP server exists. Do not use readMcpResource with gitnexus:// URIs.

Install

Copy the command and run it in a terminal.

$npx skills add https://github.com/terrylica/cc-skills --skill impact

After installing, type/impactin Claude Code to confirm it loaded.

Details

From the project README

GitNexus Impact Analysis

CLI ONLY — no MCP server exists. Never use readMcpResource with gitnexus:// URIs.

Analyze the blast radius of changing a symbol — who calls it, what processes it participates in, and what tests cover it.

Self-Evolving Skill: This skill improves through use. If instructions are wrong, parameters drifted, or a workaround was needed — fix this file immediately, don't defer. Only update for real, reproducible issues.

When to Use

  • Before modifying a function with many callers
  • "What breaks if I change X?"
  • "Is it safe to modify Y?"
  • "What's the blast radius of changing Z?"

Workflow

Step 0: Pre-flight — Ensure CLI Is Callable

The gitnexus binary is installed via npm/mise. The mise shim may fail if node isn't active in the current project. Run this pre-flight before any gitnexus command:

# Test if gitnexus is actually callable (not just a broken shim)
gitnexus --version 2>/dev/null || mise use [email protected]

All commands below run from the repo root. If multiple repos are indexed in the workspace, add --repo <repo-name> to specify the target. Otherwise --repo is optional.

Step 1: Auto-Reindex If Stale
gitnexus status

If stale (indexed commit ≠ HEAD), automatically reindex before proceeding — do not ask the user:

gitnexus analyze

Then re-check status to confirm index is current.

Step 2: Upstream Blast Radius
gitnexus impact "<symbol>" --depth 3

This shows everything that depends on the symbol (callers, transitive callers up to depth 3).

If multiple candidates are returned, disambiguate:

gitnexus impact "<symbol>" --uid "<full-uid>" --depth 3
# or
gitnexus impact "<symbol>" --file "<file-path>" --depth 3
Step 3: Downstream Dependencies (Optional)
gitnexus impact "<symbol>" --direction downstream --depth 3

Shows what the symbol depends on — useful for understanding if dependencies might change.

Step 4: Test Coverage
gitnexus impact "<symbol>" --include-tests

Shows which test files exercise this symbol.

Step 5: Risk Assessment

Based on the number of direct dependents:

DependentsRisk LevelRecommendation
< 5LOWSafe to modify with basic testing
5–20MEDIUMReview all callers, run related tests
20–50HIGHConsider backward-compatible API, extensive testing
50+CRITICALNeeds deprecation strategy, phased migration
Step 6: Structured Report

Present:

  • Risk level with dependent count
  • Top affected processes — execution flows that include this symbol
  • Direct callers — functions/methods that call this directly
  • Test coverage — tests that exercise this symbol (or gaps)
  • Recommendation — safe to modify, needs tests, needs migration plan

Example

User: "What breaks if I change RangeBarProcessor?"

gitnexus impact "RangeBarProcessor" --depth 3
gitnexus impact "RangeBarProcessor" --include-tests

Output: "CRITICAL risk — 73 dependents across 12 processes. 8 test files cover it. Recommend backward-compatible changes only."

Post-Execution Reflection

After this skill completes, reflect before closing the task:

  1. Locate yourself. — Find this SKILL.md's canonical path before editing.
  2. What failed? — Fix the instruction that caused it.
  3. What worked better than expected? — Promote to recommended practice.
  4. What drifted? — Fix any script, reference, or dependency that no longer matches reality.
  5. Log it. — Evolution-log entry with trigger, fix, and evidence.

Do NOT defer. The next invocation inherits whatever you leave behind.

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