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implement-spec

implement-spec is a skill for Claude Code, Codex from baleen37/bstack. It costs 18 tokens per session (591 once invoked), scanned A, a copy of implement-spec, MIT.

A workflow for implementing a software specification in code. It organizes related tickets as a task graph, where some tasks must finish before others can begin, and uses separate agents for exploration and implementation when appropriate.

In plain words
What is it for?
Use it to turn a specification and its tickets into a complete implementation on one branch, including codebase research and parallel work.
Why use it?
It helps manage large, dependent implementation work without treating tickets as one simple list of steps. Shared notes and pointers reduce repeated explanations between agents.

Skill for Claude CodeCodex

Written for Claude Code and Codex: disable-model-invocation in frontmatter, but also agents/openai.yaml present. Also seen: mentions subagents.

Part of the mattpocock-skills plugin — 26 skills shipped together

not rated 4repo changed 1mo ago A scan 18 tokens copy · 100% MIT

Good fit Use it to turn a specification and its tickets into a complete implementation on one branch, including codebase research and parallel work.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/baleen37/bstack/implement-spec
View source ↗ baleen37/bstack
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.

Any agent
npx skills add baleen37/bstack --skill implement-spec
Clone the repo
git clone --depth 1 https://github.com/baleen37/bstack

Made for: Claude Code, Codex.

Or install mattpocock-skills, the plugin that ships this one along with the rest of its 26 skills.

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 implement-spec

README.md
[![agentmods](https://agentmods.dev/badge/skills/baleen37/bstack/implement-spec/github.svg)](https://agentmods.dev/skills/baleen37/bstack/implement-spec)
Your own site
<a href="https://agentmods.dev/skills/baleen37/bstack/implement-spec"><img src="https://agentmods.dev/badge/skills/baleen37/bstack/implement-spec/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 implement-spec

Your own site · 80×15
<a href="https://agentmods.dev/skills/baleen37/bstack/implement-spec"><img src="https://agentmods.dev/badge/skills/baleen37/bstack/implement-spec.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 18 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 591 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 100% 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 $0.00018 $0.00591
Opus 5.5 $0.00007 $0.00236
Sonnet 5.5 $0.00004 $0.00118
Haiku 4.5 $0.00002 $0.00059

Measured 1mo ago against content hash 7a22dd2e60b8, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

implement-spec 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 1mo 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

100% identical to implement-spec — 6 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.

plugins/mattpocock-skills/skills/implement-spec/SKILL.md · 41 lines

What it actually says

You have been provided a spec. This spec should have tickets associated with it, describing how to implement the spec.

The issue tracker should have been provided to you. If not, tell the user to run /setup-matt-pocock-skills.

The goal is the entire spec implemented on a single integration branch, with every ticket resolved the way the issue tracker closes work.

The tickets are not a list of steps. They are a task graph with blocking relationships between them. This means there is always a frontier of tickets which are ready to be grabbed.

Communication to and from subagents should be sparse. Communicate primarily through context pointers: to the spec, tickets, research notes, and previous commits. Don't duplicate information already available via pointers.

Implementer subagents should be run in the background where possible for maximum concurrency.

Steps

  1. Read the spec and tickets to understand the task graph.

  2. (optional) Use an exploration subagent to conduct any exploration required by the tickets - relevant codebase files or external documentation. Ensure the exploration subagent can save files - it should save its markdown notes in a directory outside the repo, accessible by all future subagents. This lets implementer subagents focus on implementation rather than exploration.

  3. Create the integration branch. If the issue tracker closes work through PRs, or the user asks for one, open a draft PR after the first merge in step 5 (a branch with no commits ahead of main can't open one), marked as closing the spec and tickets.

  4. Use implementer subagents to implement each ticket, each in its own worktree on its own branch. Each implementer subagent:

    • confirms its worktree is based on the integration branch before starting, and resets onto it if not;
    • calls the Skill tool with tdd to build the ticket;
    • merges the integration branch tip into its own branch before reporting done

  5. Once an implementer subagent completes, merge its work to the integration branch with a merger subagent.

  6. If this changes the frontier of available tickets, kick off more implementer subagents to work on the new tickets. This allows for maximum concurrency.

  7. Once all tickets are complete, call the Skill tool with code-review on the integration branch. Fix all issues raised by the code review in a single implementer subagent.

  8. If a draft PR exists, mark it ready for review. Otherwise, resolve each ticket the way the issue tracker closes work, and report the integration branch.

  9. Clean up all implementer subagent worktrees.

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. 1mo ago Changed · +5 lines · +9 tokens per session 7a22dd2e60b8
  2. 1mo ago Changed a5b12b332b12
  3. 2mo ago First seen · 36 lines · 9 tokens per session scan A f703b5f41df9

Subscribe to this mod's changes

implement-spec is a skill published in the GitHub repository baleen37/bstack (4 stars, last pushed 1mo ago), licensed MIT. It adds 18 tokens to every session and 591 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to implement-spec, differing in 6 lines, and is treated as a copy.

Planning
Related

implement-spec compared with skills from other repositories

implement-spec next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
implement-specbaleen37/bstackSkill41mo agoMITA18Claude Code, Codex
imagegenopenai/codexSkill133kyesterdayApache-2.0A113Codex
playwright-climicrosoft/playwrightSkill99kyesterdayApache-2.0A19Claude Code
local-ai-agentsmicrosoft/ai-agents-for-beginnersSkill79k4d agoMITA200Claude Code, Codex
systematic-debuggingobra/superpowersSkill313k3d agoMITA21Claude Code
next-cache-components-adoptionvercel/next.jsSkill143kyesterdayMITA95Claude Code
next-partial-prefetching-adoptionvercel/next.jsSkill143kyesterdayMITA103Claude Code