spec-anchored-agentic-development: Skill for Claude Code

.agents/skills/explain/SKILL.md

explain is a skill for Claude Code, Codex from w00fx/spec-anchored-agentic-development. It costs 49 tokens per session (1,962 once invoked), scanned A, original, MIT.

A skill that creates a self-contained interactive HTML walkthrough of completed changes. It explains what changed, how it works, and why, using the diff together with the specification, plan, decisions, lessons, and project rules.

In plain words
What is it for?
Use it after implementation, or for a branch or pull request, to create a detailed walkthrough in the documentation walkthroughs folder.
Why use it?
A code diff alone may not explain the original intent or the decisions behind a change. This produces a readable record that connects the implementation to its requirements and design context.

Skill for Claude CodeCodex

Written for Claude Code and Codex: disable-model-invocation in frontmatter, but also agents/openai.yaml present. Also seen: installed under .agents/ (shared by several agents).

This is w00fx/spec-anchored-agentic-development's own configuration. It tells Claude Code and Codex how to work on spec-anchored-agentic-development itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything spec-anchored-agentic-development configures →

Reuse

Borrowing it

Nothing to install: this file belongs to w00fx/spec-anchored-agentic-development. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/w00fx/spec-anchored-agentic-development/main/.agents/skills/explain/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/w00fx/spec-anchored-agentic-development

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.

agentmods badge for explain

README.md
[![agentmods](https://agentmods.dev/badge/skills/w00fx/spec-anchored-agentic-development/explain.svg)](https://agentmods.dev/skills/w00fx/spec-anchored-agentic-development/explain)
Your own site
<a href="https://agentmods.dev/skills/w00fx/spec-anchored-agentic-development/explain"><img src="https://agentmods.dev/badge/skills/w00fx/spec-anchored-agentic-development/explain.svg" alt="Measured on agentmods" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,962 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 $0.00049 $0.01962
Opus 5 $0.00024 $0.00981
Sonnet 5 $0.00010 $0.00392
Haiku 4.5 $0.00005 $0.00196

Measured 3d ago against content hash dae24416071a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, 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 3d 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.

.agents/skills/explain/SKILL.md · 143 lines

How it starts

The opening of the file, as written. The whole thing — 143 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Generate a complete reference walkthrough of the changes in the argument — the work just completed in this session by default, or a diff/branch/PR if given. The goal is a document the human can read end to end and come away knowing exactly what was built and why, with nothing material left out.

Gather the full context first

Do not walk the diff blind. Read, and use as the backbone of the explanation:

  • The diff of all changes (the what).
  • The capability spec and the approved plan (protocol Phase 3) (the intent — what was asked and which approach was committed).
  • The decisions captured in Phases 1.5 and 2, including the tradeoffs (the why, which the code does not contain).
  • The lessons and any low-confidence decisions from Phase 6.
  • The constitution (for the domain rules the change touches).

The intent artifacts are what make this more than a code re-narration: explain the change against what it was supposed to do, not in a vacuum.

When the target is work from another session (a diff, branch, or PR), the intent artifacts aren't in this conversation: pull the plan from the PR description (both implement skills put it there) or the run log under .agent-runs/<run-id>/. If an intent artifact is genuinely unavailable, say which dimensions lack it — do not reconstruct intent from the code and present it as the plan.

The bar: complete in coverage, not in granularity

Cover every dimension below — leave none out. But explain at the level of why and how it connects, not line by line. If a paragraph could be replaced by reading the code, cut it; spend the words on what the code does not say (the reason, the constraint, the cross-file flow, the edge case). "Exhaustive" means no dimension missing, not every line narrated. There is no length limit — let completeness set the length. And when behavior resists prose — a scheduler, a state machine, a data flow you can only feel by stepping through it — offer a throwaway comprehension tool alongside the document (a custom debugger, a step-through UI, a time-scrubber): agents can write code that helps humans understand code; keep the understanding, delete the tool. And for behaviors with state or permissions, cover the behavior-unit checklist: trigger → rule → state change → execution path (including failure) → edge cases, each step with its evidence link — prose explains; facts anchor.

Read the full file on GitHub · 143 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 3d ago First seen · 143 lines · 49 tokens per session scan A dae24416071a

Subscribe to this mod's changes

explain is a skill published in the GitHub repository w00fx/spec-anchored-agentic-development (5 stars, last pushed 5d ago), licensed MIT. It adds 49 tokens to every session and 1,962 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.

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