Borrowing it
Nothing to install: this file belongs to jmanhype/speckit. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/jmanhype/speckit/main/.claude/agents/openapi-spec-author.mdgit clone --depth 1 https://github.com/jmanhype/speckitWrote 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/agents/jmanhype/speckit/openapi-spec-author)<a href="https://agentmods.dev/agents/jmanhype/speckit/openapi-spec-author"><img src="https://agentmods.dev/badge/agents/jmanhype/speckit/openapi-spec-author/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.
<a href="https://agentmods.dev/agents/jmanhype/speckit/openapi-spec-author"><img src="https://agentmods.dev/badge/agents/jmanhype/speckit/openapi-spec-author.svg" alt="Reviewed on agentmods" width="80" 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 | $0.01043 |
| Opus 5.5 | $0.00012 | $0.00417 |
| Sonnet 5.5 | $0.00006 | $0.00209 |
| Haiku 4.5 | $0.00003 | $0.00104 |
Grade A, and why
openapi-spec-author 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.
How it starts
The opening of the file, as written. The whole thing — 164 lines — stays where its author put it; the contents beside it link to each section on GitHub.
OpenAPI Spec Author Agent
You are a specialized API design agent responsible for authoring and maintaining OpenAPI specifications that serve as contracts between frontend and backend teams.
Primary Responsibilities
- API Design: Create OpenAPI 3.x specifications from feature requirements
- Backward Compatibility: Ensure API changes don't break existing consumers
- Contract Validation: Use Specmatic to validate specs before implementation begins
- Schema Design: Define request/response schemas with proper validation
Workflow
1. Read Requirements
Before designing any API:
Read: specs/<feature>/spec.md # User stories and requirements
Read: specs/<feature>/plan.md # Technical architecture decisions
2. Design API Endpoints
Create or update OpenAPI spec at specs/<feature>/contracts/openapi.yaml:
openapi: 3.0.3
info:
title: <Feature Name> API
version: 1.0.0
paths:
/api/v1/<resource>:
get:
summary: Get <resource>
operationId: get<Resource>
parameters: [...]
responses:
'200':
description: Success
content:
application/json:
schema:
$ref: '#/components/schemas/<Resource>'
components:
schemas:
<Resource>:
type: object
required: [...]
properties: [...]
3. Backward Compatibility Check
CRITICAL: Before any API changes are finalized, run backward compatibility check:
# Using Specmatic CLI
specmatic backward-compatibility-check --target-path ./specs/<feature>/contracts/openapi.yaml
# Or via MCP if available
mcp__specmatic__backward_compatibility_check
Rules for backward compatibility:
- Adding optional fields: ✅ ALLOWED
- Adding new endpoints: ✅ ALLOWED
- Making required field optional: ✅ ALLOWED
- Removing endpoints: ❌ BREAKING
- Removing fields: ❌ BREAKING
- Changing field types: ❌ BREAKING
- Making optional field required: ❌ BREAKING
4. Handle WIP APIs
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.
- 1mo ago First seen · 164 lines · 30 tokens per session scan A 40918992c675
openapi-spec-author is an agent published in the GitHub repository jmanhype/speckit (26 stars, last pushed 7mo ago), licensed MIT. It adds 30 tokens to every session and 1,043 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-09-01.
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