spec-execution

spec-execution is a skill for Claude Code, Codex from a5c-ai/babysitter. It costs 30 tokens per session (404 once invoked), scanned A, original, MIT.

A structured workflow for turning a written feature specification into code, tests, review findings, commits, and progress reports. It works through the specification in phases and repeats improvements when quality checks find problems.

In plain words
What is it for?
Use it to implement multi-step features, write unit and integration tests, review acceptance criteria, fix issues, create organized Git commits, and track completion.
Why use it?
It reduces the chance that requirements, edge cases, tests, or error handling are forgotten during implementation. It also makes unfinished work and quality issues visible.

Skill for Claude CodeCodex

About the project

Babysitter is a workflow engine for AI coding agents that enforces predefined steps, quality checks, human approvals, and decision records. It is used to coordinate complex, repeatable agent workflows across supported coding tools. The catalogue contains skills, agents, instructions, settings, a plugin, and an MCP integration for its workflow.

a5c-ai/babysitter · 1,769 stars · on GitHub

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/a5c-ai/babysitter/spec-execution
Any agent
npx skills add a5c-ai/babysitter --skill spec-execution
Clone the repo
git clone --depth 1 https://github.com/a5c-ai/babysitter

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-execution

README.md
[![agentmods](https://agentmods.dev/badge/skills/a5c-ai/babysitter/spec-execution.svg)](https://agentmods.dev/skills/a5c-ai/babysitter/spec-execution)
Your own site
<a href="https://agentmods.dev/skills/a5c-ai/babysitter/spec-execution"><img src="https://agentmods.dev/badge/skills/a5c-ai/babysitter/spec-execution.svg" alt="Measured on agentmods" height="20"></a>
Per session 30 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 404 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 $0.00030 $0.00404
Opus 5 $0.00015 $0.00202
Sonnet 5 $0.00006 $0.00081
Haiku 4.5 $0.00003 $0.00040

Measured yesterday against content hash 143fe357763f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

spec-execution 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 yesterday.

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.

library/methodologies/claudekit/skills/spec-execution/SKILL.md · 60 lines

What it actually says

  • Read specification for requirements and architecture
  • Implement each requirement following project conventions
  • Add type definitions and JSDoc documentation
  • Implement error handling for all failure modes

Phase 2: Test Writing

  • Write unit tests for each module/function
  • Write integration tests for API boundaries
  • Cover all acceptance criteria from the specification
  • Test edge cases and error paths

Phase 3: Code Review

  • Verify all requirements are implemented
  • Check acceptance criteria are tested
  • Review architecture adherence
  • Assess code quality

Phase 4: Iterative Improvement

  • Address review findings
  • Fix failing tests
  • Resolve architecture deviations
  • Re-verify quality (convergence loop, max 3 cycles)

Phase 5: Atomic Commit

  • Group changes into logical atomic commits
  • Descriptive messages following project conventions
  • Separate production, test, and config changes
  • Include specification reference

Phase 6: Progress Tracking

  • Requirement completion percentage
  • Test coverage summary
  • Quality score report
  • Remaining work identification

Quality Gate

Quality threshold defaults to 80. If not met after max improvement cycles, a human breakpoint is triggered for review.

When to Use

  • /spec:execute [file] slash command
  • After spec creation when ready to implement

Processes Used By

  • claudekit-spec-workflow (execute mode)
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. yesterday First seen · 60 lines · 30 tokens per session scan A 143fe357763f

Subscribe to this mod's changes

spec-execution is a skill published in the GitHub repository a5c-ai/babysitter (1,769 stars, last pushed today), licensed MIT. It adds 30 tokens to every session and 404 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 2026-09-03.

Related

Other skills, from other repositories

tutti-app-release

Set up, review, run, or debug external repositories that publish a Tutti workspace app through the reusable Tutti App Release GitHub Actions workflow. Use for caller workflows, tutti.app.json manifests, @tutti-os/app-release-tools, S3/CloudFront release hosting, latest.json, versions.json, catalog.json, catalog-only…

tutti-os/tutti · 80 tokens

tutti-agent-workspace-app

Build or evolve a complex agent-enabled Tutti workspace app repository. Use for Tutti apps with web/server/shared monorepos, @tutti-os/agent-acp-kit local agent runtimes, kit-owned TUTTICLI agent/composer discovery, dynamic agent catalogs, run-scoped MCP tool gateways, app-owned package builders, web-first debugging…

tutti-os/tutti · 106 tokens

moai-ref-testing-pyramid

Test pyramid strategy, coverage targets, test patterns, and quality metrics reference. Agent-extending skill that amplifies manager-develop test-creation and quality-validation work with production-grade testing patterns. NOT for: production code implementation, architecture design, DevOps, security audits.

modu-ai/moai-adk · 61 tokens

nw-hexagonal-testing

5-layer agent output validation, I/O contract specification, vertical slice development, and test doubles policy with per-layer examples.

nWave-ai/nWave · 29 tokens

groom-backlog

Grooms a project backlog and proposes tracker changes. Trigger on "groom the backlog", "groom the board", "clean up the backlog", or "/groom-backlog"; changes require user approval.

bostonaholic/team · 47 tokens

pr-watch-as-reviewer

Watches a reviewed PR and approves settled feedback. Trigger on "approve the PR when my comments are resolved", "watch and approve", or "/pr-watch-as-reviewer"; user-invoked only.

bostonaholic/team · 47 tokens