| name | debug-performance |
| description | Improve performance in Codex by measuring baseline behavior, isolating hot paths, implementing focused optimizations, and confirming wins with before/after numbers. |
| compatibility | Codex CLI with terminal access, git (tokenlean CLI optional) |
Debug Performance (Codex)
Measure first. Optimize second.
Workflow
Measure -> Isolate -> Analyze -> Optimize -> Confirm
1. Measure
time <command>
Capture baseline metrics (latency, throughput, memory) before edits.
2. Isolate
rg -n "<slow operation symbol>" src
rg -n "for |while |map\(|filter\(|reduce\(" <suspect-file>
Prioritize hot paths and repeated work.
3. Analyze
Inspect only relevant functions/loops/I/O:
sed -n '1,260p' <suspect-file>
Check for:
- N^2 loops
- Repeated expensive I/O
- Heavy initialization on hot paths
- Work that can be cached or deferred
4. Optimize
- Use the smallest optimization with clear impact.
- Preserve behavior and API.
- Prefer algorithmic improvements over micro-optimizations.
5. Confirm
time <same command>
npm test
Report before/after numbers. No numbers means no verified gain.
Tips
- Do not optimize cold paths.
- Keep benchmark input stable between runs.
- If tradeoffs exist (speed vs memory), document them explicitly.
