debug-flow

A structured debugging workflow that reproduces a problem, traces its root cause, writes a failing test, applies a fix, and verifies the result.

In plain words
What is it for?
Use it for reported bugs, unexpected output, intermittent test failures, and production errors, including checking recent changes and running the full test suite.
Why use it?
It replaces guesswork and symptom-fixing with a repeatable process for understanding why code or tests fail.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/dvnghiem/flowdeck/debug-flow
Any agent
npx skills add DVNghiem/FlowDeck --skill debug-flow
Clone the repo
git clone --depth 1 https://github.com/DVNghiem/FlowDeck

Made for: Claude Code, Codex.

Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 703 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00034 $0.00703
Opus 5 $0.00017 $0.00351
Sonnet 5 $0.00007 $0.00141
Haiku 4.5 $0.00003 $0.00070

Measured 2d ago against content hash 4134d4458d43, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

debug-flow scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

src/skills/debug-flow/SKILL.md · 76 lines

How it starts

The opening of the file, as written. The whole thing — 76 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Debug Flow Skill

Finds root causes through systematic investigation. Does not guess. Does not fix symptoms.

When to Activate

Activate when:

  • A bug has been reported
  • Code is producing unexpected output
  • Tests are failing intermittently
  • An error is occurring in production

Core Principles

  • Read stack traces completely — never skip to the middle
  • Fix root causes, not symptoms
  • Check recent changes first — git log --oneline -20
  • Reproduce before fixing — if you can't reproduce it, you don't understand it

Workflow

  1. Reproduce — confirm you can make the bug happen reliably
  2. Read the full stack trace — start from the top (error), trace to the origin
  3. Check recent changesgit log --oneline -20 to find what changed
  4. Trace execution backward — what called the failing function? What state did it receive?
  5. Identify root cause — the earliest point where invariants are violated
  6. Write a failing test — one test that fails with the bug present
  7. Fix — change the minimum code to make the test pass
  8. Verify — run the full test suite

Common Root Causes

Symptom Likely Cause Investigation
Cannot read property of undefined Missing null check upstream Trace where undefined enters
Wrong calculation result Type coercion ("5" + 3 = "53") Check input types
Race condition / intermittent Missing await Find async functions called without await
Auth bypass Missing middleware Check route definition vs working routes
Infinite loop Wrong termination condition Log loop counter, check exit logic
Memory leak Event listener not cleaned up Check useEffect returns, removeListener calls
Promise rejection unhandled Missing .catch() or try/catch Check all async call sites
Type error at runtime as any hiding real type Find where the cast was added
Stale data in UI Cache not invalidated Check cache keys and invalidation logic
Import error Circular dependency or missing export npx madge --circular src/

Read the full file on GitHub · 76 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 76 lines · 34 tokens per session scan A 4134d4458d43

Subscribe to this mod's changes

debug-flow is a skill published in the GitHub repository DVNghiem/FlowDeck (24 stars, last pushed 13d ago), licensed MIT. It adds 34 tokens to every session and 703 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other skills, from other repositories

oh-my-opencode-slim

Configure and improve oh-my-opencode-slim for the current user. Use when users want to tune agents, models, prompts, custom agents, skills, MCPs, presets, or plugin behavior. Also use when recurring workflow friction suggests a safe config or prompt improvement.

alvinunreal/oh-my-opencode-slim · 61 tokens

reflect

Review recent work, find repeated workflow patterns, and suggest reusable skills, agents, commands, config changes, or playbooks. Use when the user asks to learn from past sessions, improve recurring workflows, or identify what should be turned into reusable agent instructions.

alvinunreal/oh-my-opencode-slim · 53 tokens

clonedeps

Clone important project dependency source code into an ignored local workspace so OpenCode can inspect library internals. Use when the user asks to clone dependencies, inspect dependency/source internals, understand SDK/framework behavior from source, debug library implementation details, or make core dependency repos…

alvinunreal/oh-my-opencode-slim · 76 tokens

codemap

Generate comprehensive hierarchical codemaps for UNFAMILIAR repositories. Expensive operation - only use when explicitly asked for codebase documentation or initial repository mapping.

alvinunreal/oh-my-opencode-slim · 34 tokens

deepwork

High-cost orchestrator workflow for large, high-risk, multi-phase coding efforts with meaningful dependencies and review gates. Do not activate for routine multi-file changes.

alvinunreal/oh-my-opencode-slim · 34 tokens

worktrees

Manage Git worktrees as OMO safe isolated coding lanes for complex, risky, or parallel work.

alvinunreal/oh-my-opencode-slim · 23 tokens