Actix-web Rust web framework. Covers routing, extractors, middleware, state management, and WebSocket. Use for high-performance Rust APIs. USE WHEN: user mentions "actix-web", "actix", "rust web framework", "rust api", asks about "rust async web", "actix middleware", "actix extractors", "rust websocket", "high performance rust api" DO NOT USE FOR: Axum projects - use `axum` instead, Rocket projects - use `rocket` instead, Warp projects - use `warp` instead, non-Rust backends

Creates and configures Claude Code subagents (custom agents). Covers frontmatter fields, tool restrictions, model selection, hooks, memory, skills preloading, and common patterns. Follows official Anthropic best practices. USE WHEN: user mentions "create agent", "subagent", "custom agent", ".claude/agents", "agent file", "delegate task", "isolated context", "agent memory", "agent hooks" DO NOT USE FOR: creating skills - use `skill-authoring`; creating hooks standalone - use `hook-authoring`; creating MCP servers - use `mcp-authoring`

Agent-driven RAG patterns. Self-RAG, Corrective RAG (CRAG) with web fallback, Adaptive RAG with routing classifier, ReAct with retrieval tool, multi-hop retrieval, plan-and-execute, LangGraph state machines for RAG. USE WHEN: user mentions "agentic RAG", "Self-RAG", "Corrective RAG", "CRAG", "Adaptive RAG", "multi-hop retrieval", "LangGraph RAG", "ReAct RAG", "plan and execute RAG" DO NOT USE FOR: static retrieval pipelines - use `rag-architecture`; query rewriting only - use `query-transformations`; evaluation - use `rag-evaluation`

Angular Material and CDK for UI components, theming, and custom components. Covers standalone Material components and custom themes. USE WHEN: user mentions "Angular Material", "Material CDK", "mat-table", "mat-dialog", "Angular UI components", "Material theming", "Angular CDK" DO NOT USE FOR: Bootstrap - use CSS framework skills, PrimeNG or other Angular UI libs

Anthropic Python SDK for Claude API integration. Covers messages API, streaming, tool use, vision, error handling, and best practices. Use when building Python applications that call the Claude API. USE WHEN: user mentions "anthropic", "claude api", "anthropic sdk", "anthropic.Anthropic()", "client.messages.create", "claude-opus", "claude-sonnet", "tool_use", "streaming claude", "claude python" DO NOT USE FOR: OpenAI API, other LLM providers, JavaScript/TypeScript Anthropic SDK

Blazor Server, WebAssembly, and United (Auto) with components, interop, and render modes. Covers .NET 8+ Blazor patterns. USE WHEN: user mentions "Blazor", "Blazor Server", "Blazor WASM", "Blazor WebAssembly", "Blazor components", "render modes", "Blazor interop" DO NOT USE FOR: Angular components - use `angular`, React components - use `react`, Svelte - use `svelte`

ASP.NET Core Identity for authentication, roles, claims, and external providers. Covers Identity setup, customization, and token-based auth. USE WHEN: user mentions "ASP.NET Identity", "user authentication", ".NET auth", "roles and claims", "Identity scaffolding", "external login providers" DO NOT USE FOR: JWT-only auth without Identity, Spring Security - use `spring-security`

ASP.NET Core custom middleware, pipeline order, exception handling middleware, and request/response manipulation. USE WHEN: user mentions "middleware", "request pipeline", "exception middleware", "ASP.NET middleware", "UseMiddleware", "pipeline order" DO NOT USE FOR: Express middleware - use `express`, NestJS middleware - use `nestjs`

ASP.NET Core SignalR for real-time hubs, clients, groups, and streaming. Covers strongly-typed hubs and hub filters. USE WHEN: user mentions "SignalR", "real-time", "WebSocket", "hubs", "real-time notifications", ".NET WebSocket", "push notifications" DO NOT USE FOR: Spring WebSocket - use `spring-websocket`, Socket.IO - use Angular/React WebSocket patterns

Audit logging for compliance and security. Structured audit events, immutable logs, user action tracking, database change tracking, and regulatory compliance (SOC2, HIPAA, GDPR). USE WHEN: user mentions "audit log", "audit trail", "activity log", "change tracking", "compliance logging", "who changed what", "SOC2 logging" DO NOT USE FOR: application logging - use logging skills; error tracking - use observability skills

Authentication flow validation between frontend and backend. Covers JWT, OAuth2, token refresh, and session management sync. USE WHEN: user asks about "auth integration", "JWT validation", "token refresh", "401 handling", "authentication flow", "login integration" DO NOT USE FOR: security auditing - use security skills, OAuth provider setup - use authentication skills

axe-core - accessibility testing engine for automated WCAG compliance checks. USE WHEN: user mentions "axe", "automated accessibility testing", "a11y tests", asks about "integrating accessibility checks", "CI/CD accessibility", "Playwright accessibility", "Jest accessibility", "Vitest axe" DO NOT USE FOR: manual accessibility audits - use `wcag` skill instead

Axios - promise-based HTTP client for browser and Node.js USE WHEN: user mentions "Axios", "HTTP requests", "API calls", "interceptors", "Axios instance", asks about "how to make HTTP calls", "configure Axios", "add auth header", "handle HTTP errors" DO NOT USE FOR: Fetch API - use `http-clients` instead; ky/ofetch - use `http-clients` instead; GraphQL clients - use `graphql-codegen` instead; tRPC - use `trpc` instead

Axum Rust web framework by Tokio. Covers routing, handlers, extractors, middleware, and state. Use for ergonomic async Rust APIs. USE WHEN: user mentions "axum", "tokio web", "rust async api", "tower middleware", asks about "axum extractors", "axum state", "axum router", "rust websocket axum", "hyper server", "ergonomic rust api" DO NOT USE FOR: Actix-web projects - use `actix-web` instead, Rocket projects - use `rocket` instead, Warp projects - use `warp` instead, non-Rust backends

Batch RAG for high-volume ingest and bulk query scenarios. Covers OpenAI Batch API (50% discount, 24h SLA), Anthropic Message Batches API, Voyage AI and Cohere batch embeddings, ingestion-time vs query-time batching, async/Ray parallelism, parallel writes to vector DBs, and rate-limit coordination across workers. USE WHEN: user mentions "batch API", "OpenAI batch", "Anthropic batches", "bulk embedding", "Ray embeddings", "parallel ingest", "batch RAG" DO NOT USE FOR: streaming single-query latency - use `rag-production`; cost-dashboards - use `cost-allocation`; LLM gateway routing - use `llm-gateway`

Privacy-oriented summary; full details in [../../wallets/payment-codes/SKILL.md](../../wallets/payment-codes/SKILL.md).

Bitcoin Improvement Proposals index, organized by topic. Active soft forks, wallet standards, network protocol, format standards. Pointers to canonical text and historical context. USE WHEN: looking up a BIP number, citing a standard, or understanding the relationship between related BIPs.

Bitcoin Core descriptors wallet: createwallet, importdescriptors, multipath, ranges, watch-only, signing wallets, multisig coordination. Replaces legacy BDB wallet. USE WHEN: setting up Bitcoin Core wallet, watching xpubs, building signing pipelines via Core.

Bitcoin Core JSON-RPC interface: authentication (cookie, rpcauth), wallet vs node RPCs, common verbs (getblockchaininfo, getrawtransaction, scantxoutset, importdescriptors, walletprocesspsbt, submitpackage, testmempoolaccept), error handling. USE WHEN: scripting bitcoind, integrating a service, debugging RPC errors.

Fee estimation strategies: local mempool-based (estimatesmartfee), external APIs (mempool.space, BlockCypher), bitcoind's smart-fee algorithm, replacement bidding, fee-rate floor (incremental relay). USE WHEN: choosing a fee for a new tx, evaluating fee-bump amounts, designing fee policy for a service.