Debug

You are conducting a structured debugging session following systematic investigation methodology.

MANDATORY GRAPH LOOKUP (read before Isolate/Diagnose)

First resolve the bundled helpers:

# Locate Draft's bundled helpers (cwd is the user's project; ${CLAUDE_PLUGIN_ROOT}
# is not exported into skill Bash). See core/shared/tool-resolver.md.
DRAFT_TOOLS="${DRAFT_PLUGIN_ROOT:-$(cat ~/.cache/draft/plugin-root 2>/dev/null)}/scripts/tools"
[ -d "$DRAFT_TOOLS" ] || DRAFT_TOOLS="$(ls -d ~/.claude/plugins/cache/*/draft/*/scripts/tools 2>/dev/null | sort -V | tail -1)"
[ -d "$DRAFT_TOOLS" ] || DRAFT_TOOLS="$(ls -d ~/.claude/plugins/marketplaces/*draft*/scripts/tools 2>/dev/null | tail -1)"
[ -d "$DRAFT_TOOLS" ] || DRAFT_TOOLS="$PWD/scripts/tools"

When draft/graph/schema.yaml exists, this skill must follow the graph-first lookup contract in core/shared/graph-query.md §Mandatory Lookup Contract. During Steps 3–4 (Isolate, Diagnose):

1. Locate the suspect file's module via "$DRAFT_TOOLS/graph-arch.sh" --repo . before tracing data flow.
2. Use "$DRAFT_TOOLS/graph-callers.sh" --repo . --symbol <fn> to enumerate call sites of suspect functions — not grep.
3. Use "$DRAFT_TOOLS/graph-impact.sh" --repo . --file <path> to size the blast radius before proposing a fix.
4. Run "$DRAFT_TOOLS/hotspot-rank.sh" --repo . to know whether the file is high-fanIn (any fix needs extra caution).

Filesystem grep is reserved for source-text scans (literal error strings, stack-trace symbols when the graph misses). Use the fallback sentence on graph miss.

Red Flags — STOP if you're

See shared red flags — applies to all code-touching skills.

Skill-specific:

• Making code changes before reproducing the bug
• Guessing at the cause instead of tracing data/control flow
• Trying multiple fixes simultaneously ("shotgun debugging")
• Skipping reproduction steps because "I think I know the issue"
• Writing tests without asking the developer first (bug/RCA contexts)

No fixes without root cause investigation first.

Pre-Check

0. Capture Git Context

Before starting, capture the current git state:

git branch --show-current # Current branch name
git rev-parse --short HEAD # Current commit hash

Store this for the debug report header. The session is scoped to this specific branch/commit.

1. Verify Draft Context (Optional)

ls draft/ 2>/dev/null

Debug can run standalone (without draft context) or within a draft track. If draft/ exists, load context for richer investigation.

2. Load Draft Context (if available)

Read and follow the base procedure in core/shared/draft-context-loading.md.

Key context for debugging:

• .ai-context.md — Module boundaries, data flows, invariants (crucial for tracing)
• tech-stack.md — Language-specific debugging tools and techniques
• guardrails.md — Known anti-patterns that may be causing the issue
• draft/graph/ (MANDATORY when present) — Query "$DRAFT_TOOLS/graph-arch.sh" --repo . for dependency/module context and "$DRAFT_TOOLS/hotspot-rank.sh" --repo . for complexity awareness. Use "$DRAFT_TOOLS/graph-callers.sh" --repo . --symbol <fn> to find all callers, and "$DRAFT_TOOLS/graph-impact.sh" --repo . --file <path> to size blast radius before any fix. See core/shared/graph-query.md.

Step 1: Parse Arguments

Check for arguments:

• /draft:debug — Interactive: ask what's broken
• /draft:debug <description> — Start with the described problem
• /draft:debug track <id> — Debug within a specific track context (load spec.md, plan.md)
• /draft:debug <JIRA-KEY> — Pull context from Jira ticket via MCP

If a Jira ticket is provided:

1. Pull ticket via Jira MCP: get_issue(), get_issue_description(), get_issue_comments()
2. Extract: URLs, log paths, stack traces, reproduction steps, affected services
3. Use curl/wget to fetch any URLs mentioned (dashboards, error pages, API responses)
4. Use ssh to access log locations on remote nodes (if paths like /home/log/, node IPs mentioned)
5. Collect all gathered data into a triage context bundle

Step 2: Reproduce

Goal: Confirm the bug exists and establish reproduction steps.

1. Identify the symptom — Exact error message, unexpected behavior, or performance degradation
2. Establish reproduction steps — Minimum steps to trigger the issue consistently
3. Capture evidence — Error messages, stack traces, log output (verbatim, not summarized)
4. Classify reproducibility:
   • Always reproducible — proceed to Step 3
   • Intermittent — document frequency, conditions, patterns (time, load, data-dependent); proceed to Step 3 with the failure mode tagged intermittent in the hypothesis log
   • Cannot reproduce — halt diagnostic claims. Do not proceed to Step 4 (Diagnose) until reproduction is established or the user explicitly opts into hypothesis work without reproduction. Hypotheses formed without reproduction routinely converge on confidently-wrong root causes. If the user opts in: every hypothesis must be tagged unreproduced and the final report must mark the root cause as unconfirmed pending repro.

Reference core/agents/debugger.md Phase 1 for detailed investigation techniques.

Step 3: Isolate

Goal: Narrow the failure to a specific code path.

1. Trace data flow — Follow data from input to failure point, documenting each hop with file:line references
2. Trace control flow — Map the execution path, identify where it diverges from expected behavior

3. Differential analysis — Compare working vs failing cases:

   Aspect

   Working Case

   Failing Case

   Difference

4. Check boundaries — Reference .ai-context.md module boundaries to scope the investigation

Reference core/agents/debugger.md Phase 2 for language-specific debugging techniques.

Step 4: Diagnose

Goal: Confirm root cause with evidence.

Ground-truth gate (per hypothesis): Before forming hypothesis N, open and Read the file at the file:line you are about to cite. Quote the relevant lines in the hypothesis log. A hypothesis written from graph metadata or recollection is a Ground-Truth Red Flag G4 violation — it produces hypothesis loops on assumptions rather than evidence.

1. Form hypothesis — "The bug is caused by [X] at file:line because [evidence quoted from Read]"
2. Predict outcome — "If this hypothesis is correct, then [Y] should be observable"
3. Test minimally — Smallest possible test to prove or disprove
4. Record result — Document in hypothesis log:

If hypothesis fails: Return to Step 3 with updated understanding. After 3 failed cycles, escalate (see Error Handling). Do not increase confidence on a rejected hypothesis just because alternatives are running out — that's how anchoring bias produces wrong root causes.

Reference core/agents/debugger.md Phase 3 and core/agents/rca.md for 5 Whys analysis.

Step 5: Fix (with Developer Approval)

Goal: Fix the root cause with minimal change.

Test Writing Guardrail

STOP. Before writing any test:

ASK: "Root cause confirmed: [summary]. Want me to write a regression test for this fix? [Y/n]"

• If accepted: write regression test first (fails before fix, passes after)
• If declined: note "Tests: developer-handled" and proceed to fix

Fix Implementation

1. Minimal fix — Address root cause only, no "while we're here" improvements
2. Stay in blast radius — No changes to adjacent modules without explicit approval
3. Run existing tests — Verify no regressions
4. Document root cause — Add findings to Debug Report

Step 6: Generate Debug Report

MANDATORY: Include YAML frontmatter with git metadata. Follow core/shared/git-report-metadata.md.

Include the report header table immediately after frontmatter:

| Field | Value |
|-------|-------|
| **Branch** | `{LOCAL_BRANCH}` → `{REMOTE/BRANCH}` |
| **Commit** | `{SHORT_SHA}` — {COMMIT_MESSAGE} |
| **Generated** | {ISO_TIMESTAMP} |
| **Synced To** | `{FULL_SHA}` |

Save to:

• Track-scoped: draft/tracks/<id>/debug-report.md
• Standalone: draft/debug-report-<timestamp>.md with symlink debug-report-latest.md

TIMESTAMP=$(date +%Y-%m-%dT%H%M)
# Example: draft/debug-report-2026-03-15T1430.md
ln -sf debug-report-${TIMESTAMP}.md draft/debug-report-latest.md

Mandatory Self-Check (before debug report)

Before printing the debug report, internally verify and report:

1. Graph files queried — JSONL files loaded plus any live graph query-tool invocations.
2. Layer 1 files deliberately skipped — list any context sections skipped.
3. Filesystem grep fallback justification — for every grep/find run, name the concept it searched for.

If draft/graph/schema.yaml does not exist, set Graph files queried: NONE and use justification graph data unavailable.

Graph Usage Report (append to debug report)

Emit the canonical footer from core/shared/graph-usage-report.md §Canonical footer. The lint hook scripts/tools/check-graph-usage-report.sh validates the section on save.

Cross-Skill Dispatch

• Auto-invoked by: /draft:new-track (bug tracks — Offer tier), /draft:implement (blocked tasks — Offer tier)
• Invokes: RCA agent (core/agents/rca.md) for 5 Whys and blast radius analysis
• Feeds into: /draft:new-track spec.md (reproduction and root cause sections via Detect+Auto-Feed)
• Suggests at completion:
  • "Run /draft:regression to find the exact commit that introduced this bug"
  • "Run /draft:new-track to create a bug fix track from these findings"
• Jira sync: If ticket linked, attach debug report and post summary via core/shared/jira-sync.md

Error Handling

If cannot reproduce: Gather more context — check environment differences, ask for additional logs, check if the issue is environment-specific. If no draft context: Run standalone with generic debugging methodology. Recommend /draft:init for richer context. After 3 failed hypothesis cycles: Document all findings, list what's been eliminated, escalate — consider architectural review or external input. If MCP unavailable for Jira: Skip Jira context gathering, proceed with available information.