# Claude

> Call Claude models through RunAPI using the Anthropic Messages protocol. Use for Claude chat, streaming, vision, tools, reasoning, token counting, or an existing compatibility client that needs the conditional reference.

- Skill: `runapi-ai/claude` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add runapi-ai/claude`
- Raw SKILL.md: https://api.skillmd.com/api/skills/runapi-ai/claude/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: runapi-ai (https://skillmd.com/u/runapi-ai)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/runapi-ai/claude

---


# Claude on RunAPI

Use Anthropic Messages at `https://runapi.ai` with `POST /v1/messages` as the primary protocol.

## Primary protocol recipe

### Authenticate

Set `ANTHROPIC_API_KEY` to a RunAPI API key and `ANTHROPIC_BASE_URL` to
`https://runapi.ai`. The SDK sends `x-api-key`; Bearer authentication is also accepted.

### Send request

```python
import anthropic
client = anthropic.Anthropic(api_key="YOUR_RUNAPI_TOKEN", base_url="https://runapi.ai")
message = client.messages.create(
    model="claude-sonnet-5",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Explain this decision."}],
)
print(message.content[0].text)
print(message.usage)
```

`max_tokens` is required. For long output, use `client.messages.stream(...)`
and consume `stream.text_stream` through the terminal event. Add image blocks,
function tools, reasoning controls, or token counting only when the current
RunAPI contract verifies them for the selected exact model.

### Verify result

Require final text, `stop_reason`, and authoritative `usage`. A stream is
complete only after terminal Usage and `message_stop`. Token counting estimates
input only; actual response Usage remains authoritative.

### Stop boundaries

Correct a rejected shape once using the structured error. Retry transport once
only before any response or Usage and when replay is safe. Record a terminal
error and stop without changing model or protocol.

## Compatibility protocols

Load [compatibility protocols](references/compatibility-protocols.md) only when an existing client requires OpenAI Chat/Responses or Gemini contents.

## Supported models

| Model ID | Use when |
|---|---|
| `claude-fable-5-1` | — |
| `claude-fable-5` | Flagship state-of-the-art coding, reasoning, and vision |
| `claude-sonnet-5` | Near-Opus coding at Sonnet cost |
| `claude-opus-5` | Latest Opus frontier reasoning |
| `claude-opus-4-8` | Strongest general model |
| `claude-opus-4-7` | Previous Opus generation |
| `claude-opus-4-6` | High-end reasoning |
| `claude-sonnet-4-6` | Balanced reasoning and speed |
| `claude-opus-4-5-20251101` | Dated Opus 4.5 snapshot |
| `claude-sonnet-4-5-20250929` | Dated Sonnet 4.5 snapshot |
| `claude-haiku-4-5-20251001` | Fastest lightweight snapshot |
| `claude-opus-4-1-20250805` | Dated Opus 4.1 snapshot |

## References

- <https://runapi.ai/models/claude.md>
- <https://runapi.ai/providers/anthropic.md>
- <https://runapi.ai/models.md>