A coaching guide for finding the cause of a bug in code or pseudocode without simply replacing the learner’s solution.

Use it when you have code, know what it should do, and need help isolating a specific failure rather than receiving a rewritten answer.

It helps learners trace where their program’s behavior diverges from what they expected and understand the cause themselves.

debug-coach — Skill for Claude Code and Codex by Far-200

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.

Any agent

npx skills add Far-200/think-before-code --skill debug-coach

Clone the repo

git clone --depth 1 https://github.com/Far-200/think-before-code

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/far-200/think-before-code/debug-coach/github.svg)](https://agentmods.dev/skills/far-200/think-before-code/debug-coach)

Your own site

<a href="https://agentmods.dev/skills/far-200/think-before-code/debug-coach"><img src="https://agentmods.dev/badge/skills/far-200/think-before-code/debug-coach/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/far-200/think-before-code/debug-coach"><img src="https://agentmods.dev/badge/skills/far-200/think-before-code/debug-coach.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 80 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 2,702 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00080	$0.02702
Opus 5.5	$0.00032	$0.01081
Sonnet 5.5	$0.00016	$0.00540
Haiku 4.5	$0.00008	$0.00270

Measured 1mo ago against content hash c8f93b85a6fc, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

debug-coach 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 1mo 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.

skills/debug-coach/SKILL.md · 284 lines

How it starts

The opening of the file, as written. The whole thing — 284 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Debug Coach

Why this exists

dsa-tutor lists "debug without replacing the learner's code" as one stage among many in a full session. This skill is the deeper version of that single stage, the same way complexity-coach is the deeper version of dsa-tutor's verification question and dry-run-coach is the deeper version of its dry-run stage.

Left alone, an LLM asked to debug code drifts toward the fastest fix: read the function, spot the issue, rewrite it, done. That produces correct code and teaches nothing. This skill exists to interrupt that drift and make the learner find the bug themselves.

Boundary with neighboring skills

vs. dsa-tutor — dsa-tutor is for a learner who hasn't picked an approach yet, or is still constructing one. If no approach or code exists, this isn't the right skill; hand off to dsa-tutor.
vs. dry-run-coach — dry-run-coach traces an approach to build or verify a mental model, with or without a concrete failure yet. This skill starts from the opposite end: a specific piece of code and a specific observed failure that need to be traced back to a single divergence. If the learner has code and a bug, but hasn't actually run it against anything yet, send them through dry-run-coach's tracing discipline first — there may be nothing to debug until a real input produces a real wrong output.
vs. specification-coach — this skill requires a stated expectation to diverge from. If the learner and their team haven't agreed what the code is supposed to do, there is no expected-vs-actual mismatch yet, only an undefined requirement; that's specification-coach.

Activation

Use this skill when the learner:

has code or pseudocode they wrote themselves,
can state what it's supposed to do,
has observed it doing something else (wrong output, a crash, an infinite loop, a wrong edge case),
and wants the bug found — not the function replaced.

Non-activation

Do not use this skill when:

Read the full file on GitHub · 284 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.

1mo ago First seen · 284 lines · 80 tokens per session scan A c8f93b85a6fc

Subscribe to this mod's changes

debug-coach is a skill published in the GitHub repository Far-200/think-before-code (16 stars, last pushed 1mo ago), licensed MIT. It adds 80 tokens to every session and 2,702 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-08-31.

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