# GitNexus — Code Intelligence
This project is indexed by GitNexus as **guardrail3** (475 symbols, 1155 relationships, 34 execution flows). Use the GitNexus MCP tools to understand code, assess impact, and navigate safely.
> If any GitNexus tool warns the index is stale, run `npx gitnexus analyze` in terminal first.
## Always Do
- **MUST run impact analysis before editing any symbol.** Before modifying a function, class, or method, run `gitnexus_impact({target: "symbolName", direction: "upstream"})` and report the blast radius (direct callers, affected processes, risk level) to the user.
- **MUST run `gitnexus_detect_changes()` before committing** to verify your changes only affect expected symbols and execution flows.
- **MUST warn the user** if impact analysis returns HIGH or CRITICAL risk before proceeding with edits.
- When exploring unfamiliar code, use `gitnexus_query({query: "concept"})` to find execution flows instead of grepping. It returns process-grouped results ranked by relevance.
- When you need full context on a specific symbol — callers, callees, which execution flows it participates in — use `gitnexus_context({name: "symbolName"})`.
## When Debugging
1. `gitnexus_query({query: "<error or symptom>"})` — find execution flows related to the issue
2. `gitnexus_context({name: "<suspect function>"})` — see all callers, callees, and process participation
3. `READ gitnexus://repo/guardrail3/process/{processName}` — trace the full execution flow step by step
4. For regressions: `gitnexus_detect_changes({scope: "compare", base_ref: "main"})` — see what your branch changed
## When Refactoring
- **Renaming**: MUST use `gitnexus_rename({symbol_name: "old", new_name: "new", dry_run: true})` first. Review the preview — graph edits are safe, text_search edits need manual review. Then run with `dry_run: false`.
- **Extracting/Splitting**: MUST run `gitnexus_context({name: "target"})` to see all incoming/outgoing refs, then `gitnexus_impact({target: "target", direction: "upstream"})` to find all external callers before moving code.
- After any refactor: run `gitnexus_detect_changes({scope: "all"})` to verify only expected files changed.
## Never Do
- NEVER edit a function, class, or method without first running `gitnexus_impact` on it.
- NEVER ignore HIGH or CRITICAL risk warnings from impact analysis.
- NEVER rename symbols with find-and-replace — use `gitnexus_rename` which understands the call graph.
- NEVER commit changes without running `gitnexus_detect_changes()` to check affected scope.
## Tools Quick Reference
| `query` | Find code by concept | `gitnexus_query({query: "auth validation"})` |
| `context` | 360-degree view of one symbol | `gitnexus_context({name: "validateUser"})` |
| `impact` | Blast radius before editing | `gitnexus_impact({target: "X", direction: "upstream"})` |
| `detect_changes` | Pre-commit scope check | `gitnexus_detect_changes({scope: "staged"})` |
| `rename` | Safe multi-file rename | `gitnexus_rename({symbol_name: "old", new_name: "new", dry_run: true})` |
| `cypher` | Custom graph queries | `gitnexus_cypher({query: "MATCH ..."})` |
## Impact Risk Levels
| d=1 | WILL BREAK — direct callers/importers | MUST update these |
| d=2 | LIKELY AFFECTED — indirect deps | Should test |
| d=3 | MAY NEED TESTING — transitive | Test if critical path |
## Resources
| `gitnexus://repo/guardrail3/context` | Codebase overview, check index freshness |
| `gitnexus://repo/guardrail3/clusters` | All functional areas |
| `gitnexus://repo/guardrail3/processes` | All execution flows |
| `gitnexus://repo/guardrail3/process/{name}` | Step-by-step execution trace |
## Self-Check Before Finishing
Before completing any code modification task, verify:
1. `gitnexus_impact` was run for all modified symbols
2. No HIGH/CRITICAL risk warnings were ignored
3. `gitnexus_detect_changes()` confirms changes match expected scope
4. All d=1 (WILL BREAK) dependents were updated
## CLI
- Re-index: `npx gitnexus analyze`
- Check freshness: `npx gitnexus status`
- Generate docs: `npx gitnexus wiki`