speckit-companion: Skill for Claude Code

.agents/skills/speckit-plan/SKILL.md

speckit-plan is a skill for Claude Code, Codex from alfredoperez/speckit-companion. It costs 19 tokens per session (1,420 once invoked), scanned A, a copy of speckit-plan, MIT.

A planning workflow that turns a feature specification into design and implementation planning documents. It uses a standard plan template and can run project-specific preparation steps first.

In plain words
What is it for?
Use it to plan architecture, design decisions, affected files, and the approach for implementing a specified feature.
Why use it?
It gives developers a written technical plan before they begin coding. This reduces guesswork about how the requested feature should be built.

Skill for Claude CodeCodex

Written for Claude Code: $ARGUMENTS substitution. Also seen: installed under .agents/ (shared by several agents); mentions AGENTS.md.

This is alfredoperez/speckit-companion's own configuration. It tells Claude Code and Codex how to work on speckit-companion 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 speckit-companion configures →

Reuse

Borrowing it

Nothing to install: this file belongs to alfredoperez/speckit-companion. 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/alfredoperez/speckit-companion/main/.agents/skills/speckit-plan/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/alfredoperez/speckit-companion

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 speckit-plan

README.md
[![agentmods](https://agentmods.dev/badge/skills/alfredoperez/speckit-companion/speckit-plan/github.svg)](https://agentmods.dev/skills/alfredoperez/speckit-companion/speckit-plan)
Your own site
<a href="https://agentmods.dev/skills/alfredoperez/speckit-companion/speckit-plan"><img src="https://agentmods.dev/badge/skills/alfredoperez/speckit-companion/speckit-plan/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.

agentmods 80×15 button for speckit-plan

Your own site · 80×15
<a href="https://agentmods.dev/skills/alfredoperez/speckit-companion/speckit-plan"><img src="https://agentmods.dev/badge/skills/alfredoperez/speckit-companion/speckit-plan.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 19 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,420 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 89% 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 5.1 $0.00019 $0.01420
Opus 5 $0.00010 $0.00710
Sonnet 5 $0.00004 $0.00284
Haiku 4.5 $0.00002 $0.00142

Measured 12d ago against content hash 1cd13274eb35, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

speckit-plan 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 12d 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

89% identical to speckit-plan — 9 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.

.agents/skills/speckit-plan/SKILL.md · 148 lines

How it starts

The opening of the file, as written. The whole thing — 148 lines — stays where its author put it; the contents beside it link to each section on GitHub.

User Input

$ARGUMENTS

You MUST consider the user input before proceeding (if not empty).

Pre-Execution Checks

Check for extension hooks (before planning):

  • Check if .specify/extensions.yml exists in the project root.
  • If it exists, read it and look for entries under the hooks.before_plan key
  • If the YAML cannot be parsed or is invalid, skip hook checking silently and continue normally
  • Filter out hooks where enabled is explicitly false. Treat hooks without an enabled field as enabled by default.
  • For each remaining hook, do not attempt to interpret or evaluate hook condition expressions:
    • If the hook has no condition field, or it is null/empty, treat the hook as executable
    • If the hook defines a non-empty condition, skip the hook and leave condition evaluation to the HookExecutor implementation
  • For each executable hook, output the following based on its optional flag:
    • Optional hook (optional: true):
      ## Extension Hooks
      
      **Optional Pre-Hook**: {extension}
      Command: `/{command}`
      Description: {description}
      
      Prompt: {prompt}
      To execute: `/{command}`
      
    • Mandatory hook (optional: false):
      ## Extension Hooks
      
      **Automatic Pre-Hook**: {extension}
      Executing: `/{command}`
      EXECUTE_COMMAND: {command}
      
      Wait for the result of the hook command before proceeding to the Outline.
      
  • If no hooks are registered or .specify/extensions.yml does not exist, skip silently

Outline

  1. Setup: Run .specify/scripts/bash/setup-plan.sh --json from repo root and parse JSON for FEATURE_SPEC, IMPL_PLAN, SPECS_DIR, BRANCH. For single quotes in args like "I'm Groot", use escape syntax: e.g 'I'''m Groot' (or double-quote if possible: "I'm Groot").

  2. Load context: Read FEATURE_SPEC and .specify/memory/constitution.md. Load IMPL_PLAN template (already copied).

  3. Execute plan workflow: Follow the structure in IMPL_PLAN template to:

    • Fill Technical Context (mark unknowns as "NEEDS CLARIFICATION")
    • Fill Constitution Check section from constitution
    • Evaluate gates (ERROR if violations unjustified)
    • Phase 0: Generate research.md (resolve all NEEDS CLARIFICATION)
    • Phase 1: Generate data-model.md, contracts/, quickstart.md
    • Phase 1: Update agent context by running the agent script
    • Re-evaluate Constitution Check post-design

Read the full file on GitHub · 148 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. 12d ago First seen · 148 lines · 19 tokens per session scan A 1cd13274eb35

Subscribe to this mod's changes

speckit-plan is a skill published in the GitHub repository alfredoperez/speckit-companion (90 stars, last pushed today), licensed MIT. It adds 19 tokens to every session and 1,420 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 89% identical to speckit-plan, differing in 9 lines, and is treated as a copy.

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