# API Atlas — OpenAI + Anthropic + xAI + Gemini

Exhaustive, experimentally verified reference of **everything you can do with the OpenAI, Anthropic, xAI (Grok) and
Google Gemini public APIs** as of **2026-09-18/19**: models, endpoints, parameters, objects, streaming events, tools, agents, realtime, media,
files, batch, fine-tuning, evals, admin, pricing, rate limits, errors, headers, SDKs, security, and a
multi-provider abstraction. Machine-readable first (`generated/`), human docs second (`docs/`), runnable
examples (`examples/`) and smoke tests (`tests/`) third.

Every fact carries a **status** (`DOCUMENTED`, `LIVE_VERIFIED`, `LIVE_DISCOVERED`, `BETA`, `PREVIEW`, `LEGACY`,
`DEPRECATED`, `RETIRED`, `ACCOUNT_RESTRICTED`, `UNVERIFIED`, `FAILED_VERIFICATION`) and its **sources**
(official URL + retrieval date). Nothing is claimed "tested" unless it was actually called with a real key
(see `reports/live-requests.jsonl`).

## Start here

| Need | Go to |
|---|---|
| Overview & navigation | [`docs/index.md`](docs/index.md) |
| Which model supports what | [`docs/models/openai-models.md`](docs/models/openai-models.md) · [`docs/models/anthropic-models.md`](docs/models/anthropic-models.md) · [`docs/models/xai-models.md`](docs/models/xai-models.md) · [`docs/models/gemini-models.md`](docs/models/gemini-models.md) · `generated/compatibility/model-capability-matrix.csv` |
| Every endpoint | `generated/endpoints.csv` · [`docs/endpoints/`](docs/endpoints/) |
| Every parameter | `generated/parameters.csv` (`generated/parameters.json` for nested detail) |
| Every tool (exact `type` strings) | [`docs/tools/openai/index.md`](docs/tools/openai/index.md) · [`docs/tools/anthropic/index.md`](docs/tools/anthropic/index.md) · [`docs/tools/xai/index.md`](docs/tools/xai/index.md) · [`docs/tools/gemini/index.md`](docs/tools/gemini/index.md) · `generated/tools.json` |
| Streaming events (SSE / WebSocket) | `generated/streaming-events.json` · [`docs/openai/streaming-events.md`](docs/openai/streaming-events.md) · [`docs/openai/realtime-events.md`](docs/openai/realtime-events.md) · [`docs/anthropic/streaming.md`](docs/anthropic/streaming.md) |
| Agents platforms | [`docs/openai/agents-api.md`](docs/openai/agents-api.md) · [`docs/anthropic/managed-agents.md`](docs/anthropic/managed-agents.md) · [`docs/gemini/interactions-api.md`](docs/gemini/interactions-api.md) · [`docs/xai/responses.md`](docs/xai/responses.md) |
| Pricing | [`docs/openai/pricing.md`](docs/openai/pricing.md) · [`docs/anthropic/pricing.md`](docs/anthropic/pricing.md) · [`docs/xai/pricing.md`](docs/xai/pricing.md) · [`docs/gemini/pricing.md`](docs/gemini/pricing.md) · `generated/pricing.csv` |
| Errors & retries | [`docs/errors/openai.md`](docs/errors/openai.md) · [`docs/errors/anthropic.md`](docs/errors/anthropic.md) · [`docs/errors/gemini.md`](docs/errors/gemini.md) · [`docs/xai/authentication-headers-errors.md`](docs/xai/authentication-headers-errors.md) · [`docs/architecture/resilience.md`](docs/architecture/resilience.md) |
| Cross-provider comparisons (4 providers) | [`docs/comparisons/`](docs/comparisons/) |
| Security | [`docs/security/README.md`](docs/security/README.md) |
| Multi-provider code | [`docs/architecture/multi-provider-abstraction.md`](docs/architecture/multi-provider-abstraction.md) · `examples/shared/` |
| What was verified, what is missing | [`reports/final-report.md`](reports/final-report.md) |

## Setup

```bash
cp .env.example .env && chmod 600 .env   # add OPENAI_API_KEY / ANTHROPIC_API_KEY / XAI_API_KEY / GEMINI_API_KEY
uv venv .venv && uv pip install --python .venv/bin/python openai anthropic xai-sdk google-genai pytest pyyaml jsonschema websockets
pnpm install                              # openai + @anthropic-ai/sdk + @google/genai for the TypeScript examples
```

Run an example: `bash examples/anthropic/messages/minimal.sh`, `.venv/bin/python examples/openai/responses/minimal.py`,
`node --env-file=.env --experimental-strip-types examples/openai/responses/minimal.ts`.

Run the smoke tests (cheap by default; expensive suites are gated by `RUN_*_TESTS=true`, see `.env.example`):

```bash
.venv/bin/python -m pytest -q
```

## Re-running the atlas (change detection)

```bash
python3 scripts/update_atlas.py          # refresh indexes + crawl docs + /v1/models + rebuild + reports/changes.md
python3 scripts/build_generated.py       # rebuild generated/ from generated/fragments/
.venv/bin/python scripts/validate_fragments.py
python3 scripts/verify_links.py          # external + internal link check → reports/link-check.json
```

`reports/changes.md` lists NEW/REMOVED MODELS, ENDPOINTS, TOOLS, PRICING CHANGES, CONTEXT WINDOW CHANGES,
NEW BETA FEATURES, DEPRECATIONS and the official pages whose content changed since the last run.

## Layout

```
docs/          human documentation (openai/, anthropic/, xai/, gemini/, models/, tools/, endpoints/, errors/, comparisons/, architecture/, security/)
generated/     merged machine-readable outputs (+ fragments/ = curated inputs, + compatibility/ matrices, + capability graph)
examples/      runnable cURL / Python / TypeScript examples with verification status in each file header
tests/         pytest smoke tests (openai/, anthropic/, shared/)
scripts/       crawl, discover, build, validate, verify, update
sources/       downloaded official documentation (OpenAI 551, Anthropic 696, xAI 182, Gemini 291 pages), OpenAPI/discovery specs, SDK surfaces, sanitized live discovery
schemas/       JSON Schemas for every record type
reports/       live request log, coverage, changes, final report
```

Security rules: keys only in `.env` (600, gitignored), never in files or logs; admin endpoints are probed read-only;
all live tests use minimal payloads. See `CLAUDE.md` for the full conventions.