explain

A command that explains why Fettle, a code-checking tool, blocked or warned about the most recent edit.

In plain words
What is it for?
Use it to see which check ran, which file was examined, what violation was found, and how to fix or suppress it.
Why use it?
It shows whether the problem came from code-quality checks, a tool error, or Fettle itself, instead of leaving the decision unexplained.

Command

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/milindgaharwar/fettle/explain
Clone the repo
git clone --depth 1 https://github.com/MilindGaharwar/fettle
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 117 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 97% copy Near-identical to another mod 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 $0.00117
Opus 5 $0.00000 $0.00059
Sonnet 5 $0.00000 $0.00023
Haiku 4.5 $0.00000 $0.00012

Measured 2d ago against content hash 071056475413, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

explain 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.

Origin

This is a copy

97% identical to fettle-explain — 5 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

commands/explain.md · 21 lines

What it actually says

/fettle:explain

Explain why Fettle blocked or warned about the last edit.

Usage

When the user invokes /fettle:explain:

fettle explain

Shows for each decision:

  • Which hook ran (PreToolUse, PostToolUse, Stop)
  • Which file was checked
  • Which tool found the issue (ruff, semgrep, or infrastructure error)
  • The specific violation(s)
  • How to fix or suppress

Helps users understand: "Was this a code quality issue or a Fettle bug?"

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 · 21 lines · 0 tokens per session scan A 071056475413

Subscribe to this mod's changes

explain is a command published in the GitHub repository MilindGaharwar/fettle (2 stars, last pushed 4d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 117 tokens. A static security scan graded it A with 0 findings. It is 97% identical to fettle-explain, differing in 5 lines, and is treated as a copy.