debug-mode

An interactive debugging workflow for difficult software bugs. It uses possible explanations, runtime logs, and repeated checks with the developer.

In plain words
What is it for?
Collecting bug details, forming and testing hypotheses, adding runtime logging, and iteratively checking possible fixes.
Why use it?
It provides a structured way to investigate bugs whose cause is not obvious instead of guessing at fixes. The developer remains involved in confirming what happens.

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/doraemonkeys/claude-code-debug-mode/debug-mode
Any agent
npx skills add doraemonkeys/claude-code-debug-mode --skill debug-mode
Clone the repo
git clone --depth 1 https://github.com/doraemonkeys/claude-code-debug-mode

Made for: Claude Code, Codex.

Per session 57 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 997 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. 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 $0.00057 $0.00997
Opus 5 $0.00028 $0.00498
Sonnet 5 $0.00011 $0.00199
Haiku 4.5 $0.00006 $0.00100

Measured 2d ago against content hash 10cd53745a28, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

debug-mode scanned grade B with 1 finding 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.

Reads agent configuration directoriesmediumAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

**If fixed:** Remove all `#region DEBUG` blocks and contents (use Grep to find them), delete `.claude/debug.log`, summarize.
debug-mode/SKILL.md · 110 lines

How it starts

The opening of the file, as written. The whole thing — 110 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Debug Mode

You are in Debug Mode — a hypothesis-driven debugging workflow. Do NOT jump to fixes. Follow each phase in order.


Phase 1: Understand the Bug

Ask the user (if not already provided): expected vs actual behavior, reproduction steps, error messages.

Read the relevant source code. Understand the call chain and data flow.

Phase 2: Generate Hypotheses

Generate testable hypotheses as a numbered list:

Based on my analysis, here are my hypotheses:

1. **[Title]** — [What might be wrong and why]
2. **[Title]** — [Explanation]
3. **[Title]** — [Explanation]

Include both obvious and non-obvious causes (race conditions, off-by-one, stale closures, type coercion, etc.).

Phase 3: Instrument the Code

Log file

Write to {project_root}/.claude/debug.log using an absolute path.

project_root = hardcoded constant string inferred from context (file paths in the conversation). PROHIBITED: import.meta.dir, __dirname, process.cwd(), Deno.cwd(), path.resolve() or any runtime detection. Exception: remote/CI environments or non-writable local filesystem — use /tmp/.claude/debug.log instead.

Before each reproduction: create .claude/ if needed, then clear the log.

Server-side: file-append API (fs.appendFileSync, open("a"), etc.). Browser-side: fetch POST to a debug API route. Must work in all environments (dev/release).

Region markers

ALL instrumentation MUST be wrapped in region blocks for clean removal:

// #region DEBUG       (JS/TS/Java/C#/Go/Rust/C/C++)
# #region DEBUG        (Python/Ruby/Shell/YAML)
<!-- #region DEBUG --> (HTML/Vue/Svelte)
-- #region DEBUG       (Lua)

...instrumentation...

// #endregion DEBUG    (matching closer)

Logging rules

  • NEVER use console.logprint or any stdout/stderr output. All debug output MUST go to debug.log — server-side via file-append, browser-side via fetch to a debug API endpoint.
  • Log messages include hypothesis number: [DEBUG H1], [DEBUG H2], etc.
  • Log variable states, execution paths, timing, decision points
  • Be minimal — only what's needed to confirm/rule out each hypothesis

Read the full file on GitHub · 110 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 · 110 lines · 57 tokens per session scan B 10cd53745a28

Subscribe to this mod's changes

debug-mode is a skill published in the GitHub repository doraemonkeys/claude-code-debug-mode (111 stars, last pushed 2mo ago), licensed MIT. It adds 57 tokens to every session and 997 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 1 finding (reads agent configuration directories). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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