# API Surface

> Use when the user asks to inspect API or MCP surfaces.

- Skill: `tamnguyendinh/api-surface` (Agent Skill)
- Install (CLI): `npx skillmds@latest add tamnguyendinh/api-surface`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tamnguyendinh/api-surface/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: tamnguyendinh (https://skillmd.com/u/tamnguyendinh)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tamnguyendinh/api-surface

---


# API Surface With Anvien

Use this skill for route handlers, MCP/RPC tool handlers, generated contracts, response shape drift, route consumers, and API-impact decisions.

This skill is a workflow gate for API-surface work. It is not a command router. When a concrete Anvien command is needed, choose it directly from the generated Command Selection Guide.

## Command Choices

| Need | CLI | MCP |
|---|---|---|
| Route handlers, consumers, middleware, flows | `anvien api route-map [route] --repo <repo> --json` | `route_map` |
| MCP/tool definitions and linked flows | `anvien api tool-map [tool] --repo <repo> --json` | `tool_map` |
| Response shape drift against consumers | `anvien api shape-check [route] --repo <repo> --json` | `shape_check` |
| Route/API blast radius | `anvien api impact [route] --repo <repo> --json` | `api_impact` |
| Route impact via generic impact | `anvien impact route <route> --repo <repo> --json` | `impact` with `target_type=route` |
| MCP tool impact via generic impact | `anvien impact tool <tool> --repo <repo> --json` | `impact` with `target_type=tool` |
| Exact handler file context | `anvien context file <path> --repo <repo>` | `context` with `target_type=file` |
| Exact handler symbol context | `anvien context symbol "<handler>" --repo <repo>` | `context` with `target_type=symbol` |
| Broad API discovery | `anvien query api "<concept>" --repo <repo>` | `query` with `target_type=api` |

MCP tool names use underscores: `route_map`, `tool_map`, `shape_check`, `api_impact`. CLI commands use hyphenated subcommands under `anvien api`. Do not invent CLI commands by reusing MCP underscore names as top-level Anvien commands.

## Workflow

1. Refresh the graph with `anvien analyze --force` before graph-based API work.
2. Use `query api` for broad route/tool discovery only when the exact route or tool is unknown.
3. Use route-map/tool-map to find handlers, consumers, flows, and handler-file `handlerFile` projection data.
4. Open handler files with `context file` when you need symbol tree, file dependencies, linked tests, or unresolved handler-file sites.
5. Use shape-check before changing response contracts or generated Web contracts.
6. Use API impact before editing handlers, schemas, contracts, or shared API helpers. Use `impact route` or `impact tool` when the route/tool is the change target and you need the generic impact report shape.
7. Validate with focused backend tests and Web contract/client tests when consumers are affected.
8. Run `detect-changes --scope all` before commit.

## Evidence To Record

- Route/tool selector used and whether it was ambiguous.
- Handler file, handler-file summary, symbol tree/dependency counts, unresolved handler-file sites, consumer count, middleware, flow count, linked tests, and shape-check mismatches.
- API impact risk and affected App Layers/Functional Areas.
- Contract or generated-client validation commands.

## Current Limitations

API-surface graph quality depends on route/tool extraction and source-site resolution. If a route or tool is missing, record it as graph-quality evidence and verify source manually before concluding the API does not exist.