Architecture — AI Agents, Skills & Tools
Agents, skills, guides, tools, and commands for architecture — 45 curated resources for building with AI coding agents.
API Architect
Use this agent to design APIs — resource modeling, versioning, pagination, error contracts, REST vs GraphQL. Examples — designing a public API, reviewing an API spec, planning a breaking change.
Database Architect
Use this agent to design data models and storage strategy from access patterns — schema design, normalization vs deliberate denormalization, relational vs document vs key-value vs wide-column vs graph selection, indexing, partitioning/sharding, transaction boundaries, and consistency models. Examples — modeling a new feature's schema, choosing a database for a write-heavy event workload, reviewing a schema for missing indexes or scaling cliffs, planning how to shard a table that no longer fits one node.
GraphQL Architect
Use this agent to design GraphQL schemas and resolvers — types, nullability, connections, dataloaders, federation, depth/complexity limits. Examples — designing a new schema from requirements, killing N+1 queries in resolvers, planning a deprecation, hardening a public graph.
System Architect
Use this agent for high-level system design — service boundaries, data flow, scaling, trade-offs. Examples — designing a new system, evaluating a monolith-to-services split, a scalability review.
MCP Server Engineer
Use this agent to build, harden, or productionize a Model Context Protocol (MCP) server — designing tools/resources/prompts, choosing stdio vs. Streamable HTTP, taking a server remote with OAuth and stateless scaling, and testing it with the MCP Inspector. Examples — "wrap our internal API as an MCP server with three tools", "take our stdio server remote so the team can share it", "our tools confuse the model — fix the names, schemas, and descriptions".
Cloud Architect
Use this agent to design a cloud architecture on AWS, GCP, or Azure — compute, networking, data stores, IAM, and cost trade-offs. Examples — choosing serverless vs containers for a new service, designing a multi-account network boundary, picking a database and estimating its monthly cost.
Agent Architect
Use this agent to design a new Claude Code subagent or review an existing one — scoping, description, toolset, model, and output contract. Examples — "design an agent that triages flaky tests", "review my code-reviewer agent for scope creep", "why won't Claude auto-delegate to my agent?".
API Deprecation Planner
Plan the retirement of an API endpoint, field, event, tool, or version without surprising active consumers. Use when replacing an interface, removing legacy behavior, publishing a sunset, migrating internal or external clients, or deciding whether observed traffic is safe to turn off.
API Error Contract Designer
Design or normalize an API's error contract so clients get stable machine-readable codes, safe human messages, field-level validation details, correlation IDs, and consistent HTTP semantics. Use when adding endpoints, replacing ad hoc error strings, documenting SDK behavior, or fixing clients that branch on fragile message text.
CORS Configurator
Diagnose and fix a failing cross-origin browser request — read the exact console error, work out whether it's a simple or preflighted request, and set the minimal correct Access-Control-* response headers (including the wildcard-with-credentials trap and the OPTIONS preflight) on the server. Use when the browser blocks a fetch/XHR with a CORS error but the API itself works from curl or Postman.
GraphQL Schema Designer
Design a clean, evolvable GraphQL schema (SDL) that won't paint you into a corner — model the graph around domain types and their relationships rather than as RPC-over-GraphQL, set nullability deliberately, standardize lists with Relay connections, plan DataLoader batching for per-parent fields, and evolve by adding + @deprecated instead of versioning. Use when designing a new GraphQL API, reviewing an SDL, or migrating REST endpoints to a graph.
Idempotency Designer
Make unsafe, retryable API operations idempotent so a client retry or a network hiccup can't double-charge, double-create, or double-send — design a client-supplied idempotency key, an atomic store-and-check (unique constraint or conditional write), in-flight conflict handling, and a retention policy. Use when a POST/mutation can be retried (payments, order creation, sends, webhooks), or when duplicate side effects have already shown up in production.
MCP Server Scaffolder
Scaffold a new Model Context Protocol (MCP) server from a description — pick the SDK and transport, generate a typed first tool with a strict schema, and wire up MCP Inspector testing and the client-registration command. Use when starting a new MCP server and you want a correct, runnable skeleton instead of copying a README.
Pagination Designer
Design correct, scalable pagination (plus the filtering and sorting that ride with it) for a list endpoint — pick cursor (keyset) vs offset and justify it, define an opaque cursor with a unique tiebreaker so no row is skipped or repeated, return a consistent envelope, bound page size, and name the indexes the sort actually needs. Use when adding a list endpoint, when OFFSET pagination crawls on a large table, or when clients see duplicate or missing rows while paging.
Rate Limiter Designer
Design and implement API rate limiting that actually holds under load — pick the algorithm (token bucket vs sliding-window-counter vs fixed window) and justify it, choose the limiting key and per-tier limits, use cross-instance atomic storage, and return standard 429 signals. Use when protecting an API from abuse or scrapers, enforcing per-tier quotas, or replacing an in-memory limiter that breaks behind multiple replicas.
Webhook Handler Scaffolder
Scaffold a robust inbound webhook handler that verifies the signature on the raw body first, dedupes on the provider's event id, acknowledges fast, and processes asynchronously — the four things naive handlers get wrong. Use when wiring up events from a third party (Stripe, GitHub, Shopify, Slack, Twilio), when a provider keeps retrying because your endpoint times out or 500s, or when duplicate events are double-charging or double-creating records.
Adr Writer
Write an Architecture Decision Record capturing a decision the user describes, in Michael Nygard ADR format (Status, Context, Decision, Consequences) with an added Considered Alternatives section. Use when recording a significant architectural or technology choice.
Architecture Diagram Generator
Generate accurate architecture diagrams as Mermaid — straight from the codebase, not from imagination — by first choosing which view answers the question (container/component, sequence, ER, or state) and then reading the real entry points, module boundaries, service calls, and schema. Use when onboarding to an unfamiliar repo, documenting a system, or visualizing one complex flow.
OpenAPI Doc Writer
Produce and maintain OpenAPI documentation for an HTTP API. Use when documenting endpoints, request/response schemas, or generating API reference docs.
Cache Policy Designer
Design a cache policy from data ownership, freshness, privacy, invalidation, and failure requirements across browser, CDN, reverse-proxy, application, and data caches. Use when adding caching, debugging stale responses, reviewing Cache-Control behavior, reducing origin load, or deciding whether a value can be cached safely at all.
Extract Module
Split an overgrown file into cohesive, well-bounded modules — find the natural seams, design each new module's public interface before moving a line, then relocate one unit at a time keeping tests green. Use when a file has grown too large, mixes unrelated responsibilities, or every change to it forces unrelated diffs and merge conflicts.
Strangler Fig Migrator
Plan the incremental replacement of a legacy module or service using the strangler-fig pattern — grow new code around the old behind an interception seam until the old is dead, instead of a big-bang rewrite. Use when a legacy system is too risky to rewrite at once, or when migrating off a deprecated framework/dependency gradually while staying shippable and rollback-able at every step.
Data Retention Auditor
Audit where personal or sensitive data is collected, copied, retained, backed up, logged, exported, and deleted, then compare actual lifecycle behavior with stated policy. Use when adding a data field, preparing a privacy review, implementing account deletion, reducing stored data, or checking whether retention controls work across primary and secondary systems.
RBAC Designer
Design the authorization model itself — fine-grained permissions on resources composed into roles, with the right amount of resource/tenant scoping — instead of scattering role-name checks through handlers. Use when building multi-user or multi-tenant authorization, when `if user.isAdmin` checks are sprawling across the codebase, or when 'who can do what' needs a real model rather than ad-hoc gates.
Monorepo Boundary Auditor
Audit a monorepo's package boundaries, dependency direction, public entry points, ownership, build graph, and affected-test rules, then report cycles and cross-layer imports with a staged repair plan. Use when packages are tightly coupled, builds invalidate too much, teams import internals, dependency cycles appear, or a monorepo migration needs enforceable architecture boundaries.
Building an MCP Server
An accurate introduction to the Model Context Protocol: server anatomy, transports, and connecting a tool to Claude Code.
Multi-Agent Orchestration
Four patterns for coordinating multiple agents — fan-out, pipeline, orchestrator-worker, and verify/critic — and when each earns its overhead.
Idempotency Keys: Design APIs That Are Safe to Retry
Design idempotent API mutations with client keys, atomic claims, response replay, payload fingerprints, in-flight handling, TTLs, and downstream safety.
The Best MCP Servers in 2026
The MCP servers actually worth connecting in 2026 — Context7, GitHub, Chrome DevTools, Playwright, Serena, Exa, Firecrawl, and official vendor servers.
Codex MCP Setup: Connect Tools and Live Context
Connect OpenAI Codex to MCP servers through the CLI, desktop app, IDE, or config.toml — with practical scoping, OAuth, and tool-approval guidance.
Deploying a Remote MCP Server: Stateless, Streamable HTTP, and Horizontal Scaling
Take an MCP server from local stdio to a remote, multi-user HTTP service — Streamable HTTP, stateless vs. stateful sessions, OAuth, and horizontal scaling.
Connecting and Governing MCP Servers: Registries, Gateways, and Tool Sprawl
As MCP servers multiply, discovery, trust, and tool sprawl become the problem. How registries, gateways, and curation keep a growing fleet secure and usable.
MCP Ecosystem Statistics 2026
The Model Context Protocol by the numbers — SDK downloads, server counts across registries, governance facts, and growth since the Linux Foundation donation.
MCP vs A2A: AI Agent Protocols Explained
What MCP and A2A each standardize, how Agent Cards and Tasks work, why the two protocols are complementary, and who governs them now (both Linux Foundation).
10 Best Claude Skills for API Development
Choose Claude skills for error contracts, idempotency, pagination, limits, webhooks, CORS, GraphQL, OpenAPI, tools, and MCP servers.
7 Best Claude Skills for Documentation
Use Claude skills to verify code examples and create accurate READMEs, API docs, runbooks, onboarding guides, ADRs, and diagrams.
Contract Testing for Microservices: Consumer, Provider, and CI
Catch breaking service changes before deployment with consumer-driven contracts, provider verification, state fixtures, compatibility gates, and schema tests.
FastMCP
A Pythonic framework for building Model Context Protocol servers and clients — decorator-based tools, resources, and prompts, with auth and deployment built in.
MCP Inspector
The official open-source visual tool for testing and debugging Model Context Protocol servers — connect, list, and call tools, resources, and prompts.
Smithery
A registry and hosting platform for Model Context Protocol servers — discover, deploy, and connect MCP servers from one place.
Trace Data Flow
Trace how a value, field, or variable flows through the codebase from source to sink.
Estimate Effort
Produce a grounded effort and complexity estimate for a task by exploring the codebase read-only.
Plan Feature
Explore the codebase and produce an implementation plan for a feature.
Write Design Doc
Explore the codebase and write a decision-oriented design doc / RFC for a feature or system change.
Add MCP Server
Add an MCP server to the current project the safe way — pick the transport and scope, wire secrets through env vars, vet provenance, and verify the connection before trusting it.