Use Claude Sonnet 4.5 20250929 with Comfy Router

API Reference for anthropic/claude-sonnet-4-5-20250929, served by Comfy Router from Anthropic.

Quick start

Create a key at platform.comfy.org/profile/api-keys and export it as COMFY_API_KEY. The Python and TypeScript snippets use the Comfy SDKs (pip install comfy-sdk, npm install @comfyorg/sdk); the cURL snippet is the same call over raw HTTP. Model ID: anthropic/claude-sonnet-4-5-20250929 Endpoint: POST https://api.comfy.org/v2/models/anthropic/claude-sonnet-4-5-20250929

from comfy_sdk import Comfy

# Reads COMFY_API_KEY from the environment.
# The SDK automatically creates an idempotency key and reuses it for automatic retries.
with Comfy() as client:
    result = client.models.run(
        "anthropic/claude-sonnet-4-5-20250929",
        {
            "max_tokens": 16,
            "messages": [
                {
                    "content": "Reply with the single word: ok",
                    "role": "user",
                },
            ],
        },
    )

print(result)

import { comfy } from "@comfyorg/sdk";

// Reads COMFY_API_KEY from the environment.
// The SDK automatically creates an idempotency key and reuses it for automatic retries.
const { data } = await comfy.models.run("anthropic/claude-sonnet-4-5-20250929", {
  max_tokens: 16,
  messages: [
    {
      content: "Reply with the single word: ok",
      role: "user",
    },
  ],
});

console.log(data);

curl https://api.comfy.org/v2/models/anthropic/claude-sonnet-4-5-20250929 \
  -H "X-API-Key: $COMFY_API_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d "{\"max_tokens\": 16, \"messages\": [{\"content\":\"Reply with the single word: ok\",\"role\":\"user\"}]}"

Schema

Input

integer

required

Maximum number of tokens to generate before stopping.

object[]

required

Conversation turns. See Anthropic Messages API docs for the full content-block taxonomy.

object

required

Either a string shorthand or an array of content blocks (text, image, document, tool_use, tool_result, …).

string

required

Possible values: user, assistant

string

Anthropic model identifier (e.g. claude-sonnet-4-5, claude-opus-4-7).

boolean

When true, the response is a text/event-stream of Anthropic message events instead of a single JSON body.

object

Top-level system prompt. Either a string or an array of content blocks; both reach Anthropic unchanged.

Generated from the schema Router serves at GET /v2/models/anthropic/claude-sonnet-4-5-20250929/openapi.json, the same document it validates a call against before the request reaches the provider.

Output

string

object

Token usage for an Anthropic Messages API call.

object

Per-TTL breakdown of cache-write input tokens for an Anthropic Messages API call.

integer

object[]

required

The reply’s content blocks, in order. Present on every completed message; empty when the turn produced nothing.

string

The block’s text. Present on text blocks and absent on every other kind.

string

The block kind. text is the one that carries text; thinking, redacted_thinking, tool_use, server_tool_use and the tool-result blocks are the others Anthropic sends today, and the list is open.

Examples

Input

{
  "max_tokens": 16,
  "messages": [
    {
      "content": "Reply with the single word: ok",
      "role": "user"
    }
  ]
}

Output

{
  "content": [
    {
      "text": "ok",
      "type": "text"
    }
  ],
  "id": "msg_01ExampleInvalidPlaceholder",
  "model": "claude-sonnet-4-5-20250929",
  "role": "assistant",
  "stop_reason": "end_turn",
  "stop_sequence": null,
  "type": "message",
  "usage": {
    "input_tokens": 16,
    "output_tokens": 3
  }
}

Before you ship

The SDKs create an Idempotency-Key and reuse it for automatic retries. For manual retries, reuse the original key. Router can hold the connection for up to 10 minutes. When a request fails, Router sends an X-Comfy-Error-Type response header explaining why. A 422 means Router rejected the input before calling the provider. Download generated assets promptly because result URLs can expire.

Headers

Authentication, idempotency, request IDs, error buckets, retry pacing, spend limits.

Using the Router API

Model discovery, validation errors, retries, and billing.

Limitations

What Router does not do today, and what to use instead.

Develop with Comfy

Deploy ComfyUI

Run Workflows

Comfy Router

Comfy CLI

Specifications

Use Claude Sonnet 4.5 20250929 with Comfy Router

Quick start

Schema

Input

Output

Examples

Input

Output

Before you ship

Headers

Using the Router API

Limitations

​Quick start

​Schema

​Input

​Output

​Examples

​Input

​Output

​Before you ship

Headers

Using the Router API

Limitations

Quick start

Schema

Input

Output

Examples

Input

Output

Before you ship