Thrunt Debug

Debug issues using scientific method with subagent isolation.

Orchestrator role: Gather symptoms, spawn thrunt-incident-debugger agent, handle checkpoints, spawn continuations.

Why subagent: Investigation burns context fast (reading files, forming hypotheses, testing). Fresh 200k context per investigation. Main context stays lean for user interaction.

Valid THRUNT subagent types (use exact names — do not fall back to 'general-purpose'):

• thrunt-incident-debugger — Diagnoses and fixes issues

User's issue: $ARGUMENTS

Check for active sessions:

ls .planning/debug/*.md 2>/dev/null | grep -v resolved | head -5

0. Initialize Context

INIT=$(node ".github/thrunt-god/bin/thrunt-tools.cjs" state load)
if [[ "$INIT" == @file:* ]]; then INIT=$(cat "${INIT#@file:}"); fi

Extract commit_docs from init JSON. Resolve debugger model:

debugger_model=$(node ".github/thrunt-god/bin/thrunt-tools.cjs" resolve-model thrunt-incident-debugger --raw)

1. Check Active Sessions

If active sessions exist AND no $ARGUMENTS:

• List sessions with status, hypothesis, next action
• User picks number to resume OR describes new issue

If $ARGUMENTS provided OR user describes new issue:

• Continue to symptom gathering

2. Gather Symptoms (if new issue)

Use AskUserQuestion for each:

1. Expected behavior - What should happen?
2. Actual behavior - What happens instead?
3. Error messages - Any errors? (paste or describe)
4. Timeline - When did this start? Ever worked?
5. Reproduction - How do you trigger it?

After all gathered, confirm ready to investigate.

3. Spawn thrunt-incident-debugger Agent

Fill prompt and spawn:

Investigate issue: {slug}

**Summary:** {trigger}

expected: {expected}
actual: {actual}
errors: {errors}
reproduction: {reproduction}
timeline: {timeline}

symptoms_prefilled: true
goal: find_and_fix

Create: .planning/debug/{slug}.md

Task(
  prompt=filled_prompt,
  subagent_type="thrunt-incident-debugger",
  model="{debugger_model}",
  description="Debug {slug}"
)

4. Handle Agent Return

If ## ROOT CAUSE FOUND:

• Display root cause and evidence summary
• Offer options:
• "Fix now" - spawn fix subagent
• "Plan fix" - suggest /hunt-plan --gaps
• "Manual fix" - done

If ## CHECKPOINT REACHED:

• Present checkpoint details to user
• Get user response
• If checkpoint type is human-verify:
• If user confirms fixed: continue so agent can finalize/resolve/archive
• If user reports issues: continue so agent returns to investigation/fixing
• Spawn continuation agent (see step 5)

If ## INVESTIGATION INCONCLUSIVE:

• Show what was checked and eliminated
• Offer options:
• "Continue investigating" - spawn new agent with additional context
• "Manual investigation" - done
• "Add more context" - gather more symptoms, spawn again

5. Spawn Continuation Agent (After Checkpoint)

When user responds to checkpoint, spawn fresh agent:

Continue debugging {slug}. Evidence is in the debug file.

- .planning/debug/{slug}.md (Debug session state)

**Type:** {checkpoint_type}
**Response:** {user_response}

goal: find_and_fix

Task(
  prompt=continuation_prompt,
  subagent_type="thrunt-incident-debugger",
  model="{debugger_model}",
  description="Continue debug {slug}"
)

• [ ] Active sessions checked
• [ ] Symptoms gathered (if new)
• [ ] thrunt-incident-debugger spawned with context
• [ ] Checkpoints handled correctly
• [ ] Root cause confirmed before fixing

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: backbay-labs
• Source: backbay-labs/thrunt-god
• License: MIT

Install and usage instructions live in the source repository linked above.