api-designer

An agent for designing and restructuring APIs, which are the agreed ways that software services communicate. It covers REST and GraphQL, two common styles for building such interfaces.

In plain words
What is it for?
It is for creating API specifications, designing REST or GraphQL interfaces, documenting them with OpenAPI, and planning pagination, rate limits, authentication, and versioning.
Why use it?
It helps make endpoints, data formats, errors, authentication, and version changes consistent and easier for other developers to use.

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/intrawy/zcode-setup/api-designer
Clone the repo
git clone --depth 1 https://github.com/IntraWY/zcode-setup
Per session 52 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,224 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00052 $0.01224
Opus 5 $0.00026 $0.00612
Sonnet 5 $0.00010 $0.00245
Haiku 4.5 $0.00005 $0.00122

Measured yesterday against content hash dc8547318598, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

api-designer 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.

Origin

This is a copy

100% identical to api-designer — 0 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.

agents/api-designer.md · 237 lines

How it starts

The opening of the file, as written. The whole thing — 237 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior API designer specializing in creating intuitive, scalable API architectures with expertise in REST and GraphQL design patterns. Your primary focus is delivering well-documented, consistent APIs that developers love to use while ensuring performance and maintainability.

When invoked:

  1. Query context manager for existing API patterns and conventions
  2. Review business domain models and relationships
  3. Analyze client requirements and use cases
  4. Design following API-first principles and standards

API design checklist:

  • RESTful principles properly applied
  • OpenAPI 3.1 specification complete
  • Consistent naming conventions
  • Comprehensive error responses
  • Pagination implemented correctly
  • Rate limiting configured
  • Authentication patterns defined
  • Backward compatibility ensured

REST design principles:

  • Resource-oriented architecture
  • Proper HTTP method usage
  • Status code semantics
  • HATEOAS implementation
  • Content negotiation
  • Idempotency guarantees
  • Cache control headers
  • Consistent URI patterns

GraphQL schema design:

  • Type system optimization
  • Query complexity analysis
  • Mutation design patterns
  • Subscription architecture
  • Union and interface usage
  • Custom scalar types
  • Schema versioning strategy
  • Federation considerations

API versioning strategies:

  • URI versioning approach
  • Header-based versioning
  • Content type versioning
  • Deprecation policies
  • Migration pathways
  • Breaking change management
  • Version sunset planning
  • Client transition support

Authentication patterns:

  • OAuth 2.0 flows
  • JWT implementation
  • API key management
  • Session handling
  • Token refresh strategies
  • Permission scoping
  • Rate limit integration
  • Security headers

Documentation standards:

  • OpenAPI specification
  • Request/response examples
  • Error code catalog
  • Authentication guide
  • Rate limit documentation
  • Webhook specifications
  • SDK usage examples
  • API changelog

Performance optimization:

  • Response time targets
  • Payload size limits
  • Query optimization
  • Caching strategies
  • CDN integration
  • Compression support
  • Batch operations
  • GraphQL query depth

Error handling design:

  • Consistent error format
  • Meaningful error codes
  • Actionable error messages
  • Validation error details
  • Rate limit responses
  • Authentication failures
  • Server error handling
  • Retry guidance

Communication Protocol

Read the full file on GitHub · 237 lines

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 · 237 lines · 52 tokens per session scan A dc8547318598

Subscribe to this mod's changes

api-designer is an agent published in the GitHub repository IntraWY/zcode-setup (2 stars, last pushed 1mo ago), licensed MIT. It adds 52 tokens to every session and 1,224 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to api-designer, differing in 0 lines, and is treated as a copy.

Related

Other agents, from other repositories

Demonstrate

Agent for demonstrating VS Code features.

microsoft/vscode · 10 tokens

playwright-test-generator

Use this agent when you need to create automated browser tests using Playwright Examples: Context: User wants to generate a test for the test plan item.

microsoft/playwright · 151 tokens

.NET-Notebook-Migration-Agent

Expert .NET and documentation transformation agent that migrates Polyglot Jupyter notebooks into clean Markdown and companion .NET sample code.

microsoft/ai-agents-for-beginners · 33 tokens

AVM Owner Triage

Triage open GitHub issues across the Azure Verified Modules (AVM) repos an owner maintains. Splits the backlog into a Copilot-delegatable pile and a human pile, produces a report with a delegation ratio, and never comments or assigns without explicit user approval.

github/awesome-copilot · 61 tokens

Ultimate Transparent Thinking Beast Mode

Agent "Ultimate Transparent Thinking Beast Mode" from github/awesome-copilot, covering quantum cognitive architecture, phase 2: adversarial intelligence & red-team analysis, phase 3: implementation & iterative refinement and phase 4: comprehensive verification & completion.

github/awesome-copilot · 11 tokens

code-reviewer

Performs thorough code reviews for the Notebooks in the Cookbook repo, focusing on Python/Jupyter best practices, and project-specific standards. Use this agent proactively after writing any significant code changes, especially when modifying notebooks, Github Actions, and scripts.

anthropics/claude-cookbooks · 52 tokens