ijfw-debug

ijfw-debug is a skill for Claude Code from FerroxLabs/ijfw. It costs 31 tokens per session (555 once invoked), scanned A, original, MIT.

A debugging method that finds the cause of a software failure by reproducing it, narrowing it down, testing possible explanations, and verifying the fix. It also checks recent project changes and stored project notes for related clues.

In plain words
What is it for?
Use it when code is broken or not working to isolate the failing input or function, rank likely causes, apply the smallest fix, and run tests or a linter afterward.
Why use it?
It replaces guesswork and broad edits with a small, evidence-based investigation. This helps avoid changing unrelated code while fixing a bug.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the ijfw plugin — 34 skills, 22 commands, 37 agents, 6 hooks, 1 MCP server shipped together

Good fit Use it when code is broken or not working to isolate the…

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ferroxlabs/ijfw/ijfw-debug
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 FerroxLabs/ijfw --skill ijfw-debug
Clone the repo
git clone --depth 1 https://github.com/FerroxLabs/ijfw

Made for: Claude Code.

Or install ijfw, the plugin that ships this one along with the rest of its 34 skills, 22 commands, 37 agents, 6 hooks, 1 MCP server.

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.

agentmods badge for ijfw-debug

README.md
[![agentmods](https://agentmods.dev/badge/skills/ferroxlabs/ijfw/ijfw-debug.svg)](https://agentmods.dev/skills/ferroxlabs/ijfw/ijfw-debug)
Your own site
<a href="https://agentmods.dev/skills/ferroxlabs/ijfw/ijfw-debug"><img src="https://agentmods.dev/badge/skills/ferroxlabs/ijfw/ijfw-debug.svg" alt="Measured on agentmods" height="20"></a>
Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 555 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00031 $0.00555
Opus 5 $0.00015 $0.00278
Sonnet 5 $0.00006 $0.00111
Haiku 4.5 $0.00003 $0.00056

Measured yesterday against content hash 8f772a012c26, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

ijfw-debug 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 yesterday.

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.

claude/skills/ijfw-debug/SKILL.md · 53 lines

How it starts

The opening of the file, as written. The whole thing — 53 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Step 1 -- Reproduce

State the failure in one line: what was expected vs. what happened. Confirm reproducible before proceeding. If intermittent, note conditions.

Step 2 -- Check recent changes

Call ijfw_memory_recall with the symptom. Scan .ijfw/memory/ for decisions or changes from the past 7 days that touch the affected area.

If a recent change correlates with the regression, offer revert first:

Regression likely from <change> on <date>. Revert first? (y/n)

Step 3 -- Isolate

  • Narrow to the smallest reproducing case (file, function, line range).
  • Determine if failure is input-dependent, environment-dependent, or logic-dependent.
  • Read only the specific lines relevant to the hypothesis. No full-file reads.

Step 4 -- Hypothesize

List hypotheses ranked by likelihood:

H1 -- <most likely cause> -- evidence: <why>
H2 -- <next candidate>    -- evidence: <why>
H3 -- <edge case>         -- evidence: <why>

Confirm H1 before testing H2.

Step 5 -- Fix and Verify

Apply the minimal change that addresses the root cause. Do not fix adjacent issues -- log them as follow-ups. Run tests/linter after every fix. Confirm the original symptom is gone and no adjacent regression introduced. Store result: ijfw_memory_store: <what broke>, <root cause>, <fix applied>

Step 6 -- Two-strikes session reset

If two attempts at root-cause fixes both fail to clear the original symptom, stop. Do not try a third on the same hypothesis tree. Summarize in three lines: what you tried, what each attempt revealed, what you now believe is true. Then ask the user:

Two attempts didn't land it. Recommend resetting this session and starting fresh with: "<sharpened prompt>". Accumulated failed context degrades the next attempt; a fresh session with a tighter brief usually clears it on the first try.

Capture the summary in ijfw_memory_store so the next session inherits the lessons without inheriting the noise.

Output format

SYMPTOM:     <one line>
ROOT CAUSE:  <H1 confirmed or revised>
FIX:         <what changed + file:line>
VERIFIED:    yes / needs more testing
FOLLOW-UPS:  <any adjacent issues deferred>

Read the full file on GitHub · 53 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. yesterday First seen · 53 lines · 31 tokens per session scan A 8f772a012c26

Subscribe to this mod's changes

ijfw-debug is a skill published in the GitHub repository FerroxLabs/ijfw (210 stars, last pushed 6d ago), licensed MIT. It adds 31 tokens to every session and 555 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 2026-09-05.

Related

Other skills, from other repositories

systemic-issue-triage

Trigger: new issue, bug report, triage, backlog, issue flood, community report, root cause, dead-end, blocked user. Attack issues by root class, never one-by-one; fixes must shrink the system, not grow it.

Gentleman-Programming/gentle-ai · 57 tokens

issue-root-resolution

Trigger: root audit, atacar la raíz, issue roots, backlog roots, mechanism map, deletion-driven fix, resolver issues de raíz, close outdated issues. Audit and resolve issue clusters by verified root cause.

Gentleman-Programming/gentle-ai · 45 tokens

rdd-defect-workflow

Trigger: RDD, receipt-driven development, review authority, receipt/lineage, correction/recovery, delivery gate/kill switch, bounded review defects. Guide work.

Gentleman-Programming/gentle-ai · 41 tokens

bug-fixer

name: bug-fixer description: Used when the user says "this feature is broken", "getting an error", "something's not right", or reports a bug, compilation error, or runtime exception. Locates root cause through a four-stage systematic debugging process and fixes it. version: 1.2.0 updated: 2026-06-27 requires: [].

zxpmail/ReqForge · 0 tokens

reqforge-greenkeeper

name: reqforge-greenkeeper description: Used when maintaining the ReqForge repository itself and its release gates fail — pnpm test, pnpm forge-smoke, pnpm sync:discover, adapter drift, skill fixtures, loadouts, or test-demo golden path. Restores a green, synced state with minimal changes. Not for bugs in user apps…

zxpmail/ReqForge · 0 tokens

repo-consistency-sweep

Proactive defect-class detection that handles the lower-value half of code review (per Bacchelli and Bird 2013) so human reviewers stay focused on design, intent, and knowledge transfer. Catches convention drift, ordering bugs, type-safety gaps, security and multi-tenant invariants (CWE-grounded), and operability…

Mozurok/fhorja.dev · 200 tokens