fec-debug

fec-debug is a command for coding agents from bovinphang/frontend-craft. It costs 0 tokens per session (363 once invoked), scanned A, original, MIT.

A front-end debugging and repair workflow for websites and web applications. It sorts a problem into build, runtime, interface, or API categories, then investigates and verifies the cause before making a small fix.

In plain words
What is it for?
Use it for lint, type-check, test, build, JavaScript, rendering, routing, styling, responsiveness, request, timeout, CORS, cache, and data-consistency problems.
Why use it?
It gives a structured way to move from a reported symptom to evidence and a confirmed cause. This reduces guesswork when a build fails, a page goes blank, a layout breaks, or a request does not work.

Command

Part of the frontend-craft plugin — 35 skills, 8 commands, 13 agents, 5 hooks, 6 MCP servers shipped together

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 commands/bovinphang/frontend-craft/fec-debug
Clone the repo
git clone --depth 1 https://github.com/bovinphang/frontend-craft

Or install frontend-craft, the plugin that ships this one along with the rest of its 35 skills, 8 commands, 13 agents, 5 hooks, 6 MCP servers.

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 fec-debug

README.md
[![agentmods](https://agentmods.dev/badge/commands/bovinphang/frontend-craft/fec-debug.svg)](https://agentmods.dev/commands/bovinphang/frontend-craft/fec-debug)
Your own site
<a href="https://agentmods.dev/commands/bovinphang/frontend-craft/fec-debug"><img src="https://agentmods.dev/badge/commands/bovinphang/frontend-craft/fec-debug.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 363 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 $0.00000 $0.00363
Opus 5 $0.00000 $0.00181
Sonnet 5 $0.00000 $0.00073
Haiku 4.5 $0.00000 $0.00036

Measured 4d ago against content hash b487e5e8ae85, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

fec-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 4d 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.

commands/fec-debug.md · 30 lines

What it actually says

Press fec-debug-framework to perform front-end problem diagnosis and repair. First classify the problem type (build/runtime/ui/api), and then enter the corresponding diagnosis module to perform the 5-step method (classification → collection → hypothesis → verification → repair). Complex or cross-type issues can be delegated to the fec-debugger subagent.

Question type quick check

Type Typical Scenario
build lint/type-check/test/build/CI failed
runtime JS exception, white screen, component rendering error, routing exception, state loss
ui style misalignment, abnormal interaction, animation lag, responsiveness issues
api Request failure, timeout, data inconsistency, CORS, cache issues

Execution steps

  1. Read the problems described by users and classify the problem types according to fec-debug-framework Step 1.
  2. Enter the corresponding diagnostic module and perform Step 2 to collect evidence.
  3. Propose hypotheses based on evidence (Step 3) and verify them one by one (Step 4).
  4. After confirming the root cause, perform minimal repair (Step 5) and run the affected verification command.
  5. Output the diagnostic report to reports/debug-YYYY-MM-DD-HHmmss.md.

##Strong constraints

  • Don't "fix" the problem by turning off rules, removing tests, or reducing type safety
  • Not easily refactoring irrelevant code
  • Don't guess at root cause when evidence is lacking
  • It must be verified after repairing, you cannot just change it for accidents
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. 4d ago First seen · 30 lines · 0 tokens per session scan A b487e5e8ae85

Subscribe to this mod's changes

fec-debug is a command published in the GitHub repository bovinphang/frontend-craft (21 stars, last pushed 2d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 363 tokens. 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.