inventorying-api-surface

A guide for documenting a software module's public interface: the functions, classes, types, endpoints, commands, and other ways users or systems can access it.

In plain words
What is it for?
Use it when reviewing an API, planning interface changes, checking backward compatibility, or finding undocumented endpoints and extension points.
Why use it?
It helps reveal what consumers can rely on and where changes could break existing users. It also checks that public entry points connect to real data or behavior.

Skill for Claude CodeCodex

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 skills/quangphu1912/codebase-analyzer/inventorying-api-surface
Any agent
npx skills add quangphu1912/codebase-analyzer --skill inventorying-api-surface
Clone the repo
git clone --depth 1 https://github.com/quangphu1912/codebase-analyzer

Made for: Claude Code, Codex.

Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,202 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00028 $0.01202
Opus 5 $0.00014 $0.00601
Sonnet 5 $0.00006 $0.00240
Haiku 4.5 $0.00003 $0.00120

Measured 2d ago against content hash 9e84bd88278a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

inventorying-api-surface scanned grade A with 1 finding 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 2d 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.

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

- **IPC channels**: `ipcMain.handle`, `ipcRenderer.send`, Electron/Node child_process message protocols
skills/inventorying-api-surface/SKILL.md · 88 lines

How it starts

The opening of the file, as written. The whole thing — 88 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Announce at start: "Using codebase-analyzer to inventory the API surface."

Overview

Catalog every public interface: exported functions, classes, types, REST/GraphQL endpoints, and their contracts. This skill finds implicit ENTRY POINTS (how you get in: undocumented endpoints, conditionally exposed routes, IPC channels, WebSocket message types, CLI argument schemas, environment variable contracts, plugin hooks). For implicit BEHAVIORAL ASSUMPTIONS (how code expects to be used), use detect-hidden-contracts.

Process

  1. Find public exports (export, module.exports, pub fn, def with all)
  2. Map REST/GraphQL/RPC endpoints if applicable
  3. Document function signatures and type contracts
  4. Find breaking change risks (widely-used public APIs)
  5. Find undocumented public APIs
  6. Categorize by stability: stable, experimental, deprecated, internal-but-exported
  7. Map implicit entry points beyond HTTP (see Implicit Entry Points below)
  8. Trace API-to-data-flow: verify every endpoint touches data, detect endpoint chains

API-to-Data-Flow Mapping

Every endpoint should be traceable to a data mutation or query. Endpoints that don't touch data are either proxies, health checks, or dead endpoints.

Chain detection: if endpoint A's response shape matches endpoint B's request body, they are designed to be chained. That reveals intended workflows the codebase expects but may never document. Look for:

  • Response schemas that mirror request schemas on other endpoints
  • IDs returned from create endpoints that feed directly into detail endpoints
  • Pagination cursors that flow into subsequent calls
  • Field names that are identical across request/response boundaries

Implicit Entry Points

Not just HTTP: the implicit API is often larger than the explicit one. Check for:

  • IPC channels: ipcMain.handle, ipcRenderer.send, Electron/Node child_process message protocols
  • WebSocket message types: JSON message discriminators (type field), subscription channels
  • CLI argument schemas: argparse/click/ commander definitions, each flag is an API contract
  • Environment variable contracts: process.env.X reads that control behavior without being documented as config
  • Plugin hooks: extension points, event emitters, middleware registration functions, lifecycle callbacks

Read the full file on GitHub · 88 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 2d ago First seen · 88 lines · 28 tokens per session scan A 9e84bd88278a

Subscribe to this mod's changes

inventorying-api-surface is a skill published in the GitHub repository quangphu1912/codebase-analyzer (2 stars, last pushed 4mo ago), licensed MIT. It adds 28 tokens to every session and 1,202 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 1 finding (runs shell commands). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

Related

Other skills, from other repositories

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

brainstorming

You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.

obra/superpowers · 37 tokens

auto-perf-optimize

Run agent-driven VS Code performance or memory investigations. Use when asked to launch Code OSS, automate a VS Code scenario, run the Chat memory smoke runner, capture renderer heap snapshots, take workflow screenshots, compare run summaries, or drive a repeatable scenario before heap-snapshot analysis.

microsoft/vscode · 62 tokens

chat-perf

Run chat perf benchmarks and memory leak checks against the local dev build or any published VS Code version. Use when investigating chat rendering regressions, validating perf-sensitive changes to chat UI, or checking for memory leaks in the chat response pipeline.

microsoft/vscode · 51 tokens

chat-pet-sprite-creation

Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.

microsoft/vscode · 53 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens