debug

name	debug
description	Diagnose Kandev bugs, running-instance issues, UI/browser failures, and runtime behavior. Use when the user reports unexpected behavior, asks to investigate, asks to add logs/instrumentation, or when a fix needs root-cause evidence before implementing. Triage first, gather evidence safely, then hand off to /fix or /tdd for code changes.
allowed-tools	Bash(curl:*) Bash(jq:*) Bash(npx:*) Bash(scripts/kandev-instances:*) Bash(scripts/kandev-logs:*) Bash(scripts/dev-isolated:*) Bash(scripts/kandev-kill:*) Bash(go:*) Bash(rg:*) Bash(grep:*)

Debug

Diagnose efficiently and safely. Debugging produces evidence and a root-cause hypothesis; /fix turns that into a regression-tested patch.

First: Create The Pipeline

Create a visible task list:

1. Triage - classify the bug and choose the cheapest faithful path
2. Gather evidence - targeted test, debug export/logs, browser state, or instrumentation
3. Diagnose - trace the failure to root cause
4. Report or hand off - summarize evidence and invoke /fix or /tdd if code changes are needed
5. Clean up - remove temporary logs, throwaway repro tests, isolated instances, and browser sessions

Triage Gate

Pick one path before launching anything:

Class	Signals	Reference
Backend logic	validation, dedup, data shaping, workflow routing, API/service behavior	references/backend-repro.md
Live instance	user has a running instance already misbehaving and you need read-only state/logs	references/instance.md
UI/browser	layout, focus, click flow, WS-driven UI, console/network behavior	references/browser.md plus references/instance.md
Needs logs	current evidence is insufficient and instrumentation is needed	references/instrumentation.md

Rules:

• Triage before launching anything.
• Use logs and targeted tests before browser automation.
• Never mutate the user's live instance. Read-only debug export/logs are allowed; browser interaction must use your isolated instance.
• Tear down only what you started. Never pkill kandev.

Evidence Strategy

Start with the cheapest faithful reproduction:

1. Backend logic: write a throwaway focused Go repro test against the real service path. If it reproduces, convert it via /fix or /tdd.
2. Live instance: use scripts/kandev-logs <port> --export or --level error; do not relaunch.
3. UI/browser: launch scripts/dev-isolated --web, drive npx playwright-cli, and correlate console/network state with backend logs.
4. Unknown: trace from the symptom backward through code and add temporary instrumentation only where it will split the search space.

Reference Files

Load only the reference needed for the selected path:

• references/backend-repro.md - targeted Go repro tests and backend-first debugging.
• references/instance.md - instance discovery, isolated launch, logs/export, and teardown.
• references/browser.md - npx playwright-cli browser debugging against isolated instances.
• references/instrumentation.md - temporary vs persistent frontend/backend logging rules.

When To Use Instrumentation

Use references/instrumentation.md before adding:

• console.log
• logger.Warn("[DEBUG] ...")
• createDebugLogger(...)
• backend logger.Debug / logger.Info for persistent diagnosis

Temporary logs must be stripped before /commit or /pr. Persistent instrumentation stays only when it has ongoing diagnostic value.

Hand Off To Fix

When you can state:

• what fails,
• where it fails,
• why it fails,
• how to reproduce it,

then stop debugging and use /fix or /tdd to implement the regression test and patch.

Final Report

Report:

• Bug class selected
• Evidence gathered
• Root cause or strongest hypothesis
• Suggested fix path and files
• Cleanup performed
• Any remaining unknowns