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.
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.
npx skills add a5c-ai/babysitter --skill spec-driven-developmentgit clone --depth 1 https://github.com/a5c-ai/babysitterWrote 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.
[](https://agentmods.dev/skills/a5c-ai/babysitter/spec-driven-development)<a href="https://agentmods.dev/skills/a5c-ai/babysitter/spec-driven-development"><img src="https://agentmods.dev/badge/skills/a5c-ai/babysitter/spec-driven-development.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00030 | $0.00440 |
| Opus 5 | $0.00015 | $0.00220 |
| Sonnet 5 | $0.00006 | $0.00088 |
| Haiku 4.5 | $0.00003 | $0.00044 |
Grade A, and why
spec-driven-development 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 4d 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.
What it actually says
- Search for files and code related to the task description
- Identify existing patterns that the spec should follow
- Map the impact area of proposed changes
- Generate SEARCH-CONTEXT.md with findings
2. Clarifying Question Resolution
- Identify ambiguities in the task description
- Generate targeted clarifying questions
- Resolve assumptions with explicit choices
- Document decisions for traceability
3. Spec Generation
- Structure specs with: title, goals, tasks, acceptance criteria
- Decompose into atomic, testable tasks
- Define dependency graphs between tasks
- Include rollback plans and risk assessments
- Generate SPEC.md document
4. Iterative Refinement
- Accept plan-reviewer feedback
- Apply revision requests by severity
- Refine task decomposition
- Update acceptance criteria
Spec Structure
# Specification: [Title]
## Goals
- [ ] Goal 1 with measurable outcome
## Tasks
### Task 1: [Description]
- **Acceptance Criteria**: ...
- **Test Strategy**: RED->GREEN->REFACTOR
- **Complexity**: low/medium/high
- **Dependencies**: [task-ids]
## Assumptions
- Assumption 1 (validated: yes/no)
## Risks
- Risk 1: Mitigation strategy
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.
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.
- 4d ago First seen · 63 lines · 30 tokens per session scan A 09af4f079058
spec-driven-development is a skill published in the GitHub repository a5c-ai/babysitter (1,777 stars, last pushed yesterday), licensed MIT. It adds 30 tokens to every session and 440 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.
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