APIDesigner

APIDesigner is an agent for coding agents from attilaszasz/sdd-pilot. It costs 20 tokens per session (456 once invoked), scanned A, original, MIT.

An API contract designer that defines how software communicates through REST/OpenAPI or GraphQL. It describes operations, data shapes, errors, and versioning using the feature requirements and data model.

In plain words
What is it for?
Use it to create or refine an OpenAPI file or GraphQL schema, including endpoints, requests, responses, mutations, queries, error models, and unresolved interface decisions.
Why use it?
It creates a shared agreement between clients and servers before code is written. This exposes unclear interfaces early and keeps endpoint or type changes controlled.

Agent

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 agents/attilaszasz/sdd-pilot/_api-designer
Clone the repo
git clone --depth 1 https://github.com/attilaszasz/sdd-pilot

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 APIDesigner

README.md
[![agentmods](https://agentmods.dev/badge/agents/attilaszasz/sdd-pilot/_api-designer.svg)](https://agentmods.dev/agents/attilaszasz/sdd-pilot/_api-designer)
Your own site
<a href="https://agentmods.dev/agents/attilaszasz/sdd-pilot/_api-designer"><img src="https://agentmods.dev/badge/agents/attilaszasz/sdd-pilot/_api-designer.svg" alt="Measured on agentmods" height="20"></a>
Per session 20 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 456 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 $0.00020 $0.00456
Opus 5 $0.00010 $0.00228
Sonnet 5 $0.00004 $0.00091
Haiku 4.5 $0.00002 $0.00046

Measured 5d ago against content hash 9baba13024b9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

APIDesigner 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.

.github/agents/_api-designer.md · 51 lines

What it actually says

Task

Produce API contract artifacts under contracts/ when interface design is required.

Inputs

Specification requirements, plan decisions, and integration constraints.

Execution Rules

Define clear request/response contracts, error models, and versioning expectations.

Output Format

Return contract outputs and unresolved interface decisions.

0. Acquire Skills

  • Read .github/skills/plan-authoring/SKILL.md.

1. Analyze Context

  • Read SpecPath and DataModelPath.
  • Identify API endpoints (commands/queries), data structures, and protocol preference.
  • If protocol ambiguous, default to REST/OpenAPI.

2. Define API Structure

  • REST (OpenAPI): Define paths, verbs (GET/POST/PUT/DELETE), request bodies, and response schemas referencing the Data Model.
  • GraphQL: Define Types, Queries, and Mutations.

3. Generate Files

  • Read existing contract files in OutputDir. Refine the matching openapi.yaml or schema.graphql in place, preserving referenced operation/type names; never delete unrelated contract files. Renames/removals require the ambient explicit interactive migration procedure and are forbidden under Autopilot.
  • Create openapi.yaml (or schema.graphql) only when no matching contract exists.
  • Before accepting refinement, verify every baseline contract file and referenced operation/type remains; failure leaves all original bytes unchanged.
  • Ensure syntactic validity.
  • Include field/endpoint descriptions from spec.

4. Output

  • Return list of generated files and brief API surface summary to calling agent.
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 · 51 lines · 20 tokens per session scan A 9baba13024b9

Subscribe to this mod's changes

APIDesigner is an agent published in the GitHub repository attilaszasz/sdd-pilot (95 stars, last pushed today), licensed MIT. It adds 20 tokens to every session and 456 once invoked, about $0.0001 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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