spec-planning

spec-planning is a skill for Claude Code, Codex from capitalone/context-specs. It costs 125 tokens per session (3,694 once invoked), scanned A, original, Apache-2.0.

A planning tool that turns a product requirements document (PRD) and its executable test into an implementation specification. It researches the codebase and divides the work into dependency-ordered slices.

In plain words
What is it for?
Preparing implementation plans from files under a project’s PRD directory. It produces a main specification and smaller work slices whose success includes passing the PRD test.
Why use it?
It connects the requested behavior to the existing code and gives completion a testable definition. This reduces uncertainty about what to build first and how to verify it.

Skill for Claude CodeCodex

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 skills/capitalone/context-specs/spec-planning
Any agent
npx skills add capitalone/context-specs --skill spec-planning
Clone the repo
git clone --depth 1 https://github.com/capitalone/context-specs

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 spec-planning

README.md
[![agentmods](https://agentmods.dev/badge/skills/capitalone/context-specs/spec-planning.svg)](https://agentmods.dev/skills/capitalone/context-specs/spec-planning)
Your own site
<a href="https://agentmods.dev/skills/capitalone/context-specs/spec-planning"><img src="https://agentmods.dev/badge/skills/capitalone/context-specs/spec-planning.svg" alt="Measured on agentmods" height="20"></a>
Per session 125 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,694 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 $0.00125 $0.03694
Opus 5 $0.00063 $0.01847
Sonnet 5 $0.00025 $0.00739
Haiku 4.5 $0.00013 $0.00369

Measured 5d ago against content hash 68ebbbd3d7ce, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

spec-planning 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 5d 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.

skills/sdd/spec-planning/SKILL.md · 318 lines

How it starts

The opening of the file, as written. The whole thing — 318 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Spec Planning

Turn a PRD into a structured Spec Plan using Spec-Driven Development. Agent-first: this skill is invoked headless by the harness dispatcher, with the feature slug as its single argument. It reads disk, does the work, commits artifacts plus a sentinel, and exits.

Invocation Contract

Invoked by the dispatcher as: claude -p "/spec-planning <feature>", run from inside the feature worktree (the dispatcher cds into it — there is no print-mode --cwd flag).

Single argument: <feature> — kebab-case feature slug. All paths derive from this.

Inputs read from disk (paths relative to cwd):

  • prds/<feature>/prd.md — the why, user story, definition of done, constraints, out-of-scope.
  • prds/<feature>/run-prd-test.sh — executable test runner for this feature's PRD test. Exits 0 when the feature is done.
  • Any verification artifacts under prds/<feature>/ invoked by run-prd-test.sh — fixtures, LLM-judge prompts, helper test files, etc. The runner is the single contract; its internals are intentionally flexible (pure unit test, LLM-as-judge, deterministic shell checks, or any mix).
  • The current codebase.

Outputs to disk (paths relative to cwd):

  • specs/<feature>/mainspec.md
  • specs/<feature>/slices/*.md
  • specs/<feature>/.planning-done (empty sentinel)

Completion protocol (in order):

  1. Write all mainspec + slice files.
  2. git add those files, commit with a clear message, push.
  3. touch specs/<feature>/.planning-done.
  4. git add the sentinel, commit, push.

The sentinel is the final commit-and-push action, only after every other artifact is in place. The dispatcher uses only the sentinel to advance to spec-validate.

Idempotency:

  • If specs/<feature>/.planning-done already exists, exit immediately (the previous invocation completed; the dispatcher's worktree wipe will have discarded any uncommitted intermediate state).
  • If specs/<feature>/mainspec.md exists but the sentinel does not, treat as crash recovery: verify the existing artifacts are complete and self-consistent, fix any gaps, then write the sentinel.

Read the full file on GitHub · 318 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. 5d ago First seen · 318 lines · 125 tokens per session scan A 68ebbbd3d7ce

Subscribe to this mod's changes

spec-planning is a skill published in the GitHub repository capitalone/context-specs (41 stars, last pushed 11d ago), licensed Apache-2.0. It adds 125 tokens to every session and 3,694 once invoked, about $0.0006 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 2026-08-30.

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