| name | debug-discipline |
| description | A repro-first debugging procedure with reliable reproduction, fail path tracing, hypothesis disproof, breadcrumb ledger, and completion gates. Use this skill when the request mentions failing tests, regressions, unexpected behavior that needs root-cause diagnosis. |
Generated from Skill IR: debug-discipline@1
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Update the Skill IR source instead.
Debug Discipline
Use this when
Use this when triggers match: failing test, regression, unexpected behavior.
Job to be done: diagnose and fix a defect without guessing.
What to do
- Establish a reliable reproduction or stop and document what artifact or access is missing.
- Trace the fail path end-to-end until expected behavior diverges from observed behavior.
- Form ranked falsifiable hypotheses.
- Try to disprove the leading hypothesis with the smallest experiment before treating it as root cause.
- Maintain a breadcrumb ledger of each run, what changed, what happened, and what it ruled in or out.
- Implement the smallest fix that explains the failure.
- Validate against the original reproduction.
- Add regression protection when appropriate.
Evidence required
- reliable reproduction command or scenario
- observed failure
- fail path trace
- breadcrumb ledger
- hypothesis disproof result
- root cause explanation
- validation result
Bundled resources
.agent-harness/playbooks/30-debug-from-symptom.md (reference): extend the compact skill procedure with the longer repro-first debugging workflow Use when the failure is broad, the repro is unstable, or the operator needs the full debugging loop.
.agent-harness/traces/traceability-template.yaml (asset): capture breadcrumb-style evidence and next actions across multiple debugging runs Use when the investigation needs a durable trace or handoff packet.
Evaluation prompts
parser-regression: A parser refactor introduced a failing regression test. Diagnose the root cause, make the smallest fix, and show the proof. Check for: establishes a reliable reproduction; traces the failing path before editing; connects the root cause to the final validation.
intermittent-cli-failure: A CLI command fails intermittently in CI but not every local run. Use a repro-first debugging flow and avoid speculative rewrites. Check for: documents missing repro inputs if reproduction is not stable; keeps a breadcrumb ledger of experiments; avoids broad rewrites before root cause.
Forbidden behavior
- speculative fix without reliable reproduction or explicit uncertainty
- broad rewrite before root cause
- single-hypothesis anchoring without disproof
- discarding breadcrumb evidence that contradicts the chosen hypothesis
- declaring done without rerunning proof
Done when
- original failure no longer reproduces under the reliable reproduction
- root cause is connected to fix
- breadcrumb ledger is consistent with the final root cause
- relevant tests pass
This generated Claude-style skill follows the 9arm-skills shape: one skill directory, one SKILL.md, YAML frontmatter, and behavior-preserving body generated from Skill IR.