Anthropic API

Name: Anthropic API API
Brand: Anthropic API
Availability: InStock

★ Only Publicly Available OpenAPI DocumentAI/MLLanguage ModelsapiKey11 EndpointsREST

For Agents

Send prompts to Claude models for text generation, reasoning, and code tasks. Supports 200K context windows, message batching, and token counting for cost-aware agent workflows.

Quickstart

Get started with Anthropic API in minutes using your preferred integration method.

# Add to your MCP client config (Claude Desktop, Cursor, Windsurf)
{
  "jentic": {
    "url": "https://api.jentic.com/mcp",
    "auth": "oauth"
  }
}

# Then ask your agent:
"send a message to Claude for text generation"

# → Jentic returns the GET /events tool with parameter schema, agent executes.

Capabilities

What an agent can do with Anthropic API API.

Generate multi-turn conversations with Claude models using 200K token context windows

Process high-volume message requests asynchronously through batch endpoints

Count tokens before sending requests to estimate costs and manage context budgets

List and inspect available Claude model versions and capabilities

GET STARTED

Start building with Anthropic API API

Explore with Jentic

View OpenAPI Document

Jentic publishes the only available OpenAPI document for Anthropic API, keeping it validated and agent-ready.

Jentic publishes the only available OpenAPI specification for Anthropic API, keeping it validated and agent-ready. Send messages to Claude models with up to 200K token context windows for complex reasoning, analysis, and code generation across 11 endpoints. Supports message batching for high-volume async workloads, token counting for cost estimation, and model listing for version discovery. Authentication uses the x-api-key header with API key validation.

Use Cases

Patterns agents use Anthropic API API for, with concrete tasks.

★ AI Agent Reasoning via Jentic

AI agents discover and invoke Claude's message endpoint through Jentic's intent-based search for complex multi-step reasoning tasks. Agents search for the operation, receive the input schema including system prompts and tool definitions, and execute message requests without configuring API headers manually. Claude's 200K context window handles large document analysis and multi-turn conversations within a single request.

Search Jentic for 'send a message to Claude for analysis', load the POST /v1/messages schema, and execute with model claude-sonnet-4-20250514 and a 50K token document for summarization

Batch Message Processing

Submit hundreds or thousands of message requests as a single batch via POST /v1/messages/batches for asynchronous processing at reduced cost. Monitor batch status, retrieve results when complete, or cancel if no longer needed. Ideal for bulk content generation, document analysis pipelines, or evaluation runs that do not require real-time responses.

Create a message batch with 100 requests via POST /v1/messages/batches, poll GET /v1/messages/batches/{message_batch_id} for completion, then retrieve results

Token Counting for Cost Management

Estimate token usage and costs before sending requests using the POST /v1/messages/count_tokens endpoint. Pass your intended messages and system prompt to receive an exact token count without consuming model compute. Agents use this to stay within budget constraints, split large documents into appropriately-sized chunks, and choose between model tiers based on actual token requirements.

Count tokens for a 30K-word document via POST /v1/messages/count_tokens with model claude-sonnet-4-20250514 to verify it fits within the context window

Long Document Analysis and Summarization

Analyze documents up to 200K tokens in a single request using Claude's extended context window through POST /v1/messages. Handles legal contracts, research papers, codebases, and meeting transcripts without chunking or retrieval augmentation. Returns structured summaries, extractions, or analyses based on system prompt instructions.

Send a 150K token legal document to POST /v1/messages with a system prompt to extract all obligations, deadlines, and parties mentioned

Key Endpoints

11 endpoints — jentic publishes the only available openapi specification for anthropic api, keeping it validated and agent-ready.

METHOD

PATH

DESCRIPTION

POST

/v1/messages

Send messages to Claude for text generation and reasoning

POST

/v1/messages/count_tokens

Count tokens in a message without generating a response

POST

/v1/messages/batches

Create a batch of message requests for async processing

GET

/v1/messages/batches/{message_batch_id}

Retrieve status and results of a message batch

POST

/v1/messages/batches/{message_batch_id}/cancel

Cancel an in-progress message batch

GET

/v1/messages/batches/{message_batch_id}/results

Download results of a completed batch

GET

/v1/models

List all available Claude models

GET

/v1/models/{model_id}

Get details for a specific model

POST

/v1/messages

Send messages to Claude for text generation and reasoning

POST

/v1/messages/count_tokens

Count tokens in a message without generating a response

POST

/v1/messages/batches

Create a batch of message requests for async processing

GET

/v1/messages/batches/{message_batch_id}

Retrieve status and results of a message batch

POST

/v1/messages/batches/{message_batch_id}/cancel

Cancel an in-progress message batch

Why though Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

Anthropic API keys (x-api-key header) are stored encrypted in the Jentic vault (MAXsystem). Agents receive scoped access tokens — raw keys and version headers are injected automatically without entering the agent's context.

Intent-based discovery

Agents search by intent (e.g., 'analyze a long document with Claude') and Jentic returns matching Anthropic operations with their input schemas, including model options and token limits, so the agent can invoke the right endpoint without reading API docs.

Time to first call

Direct Anthropic integration: 1-2 days for auth setup, version header management, and error handling. Through Jentic: under 1 hour — search, load schema, execute.

Related APIs

Alternatives and complements available in the Jentic catalogue.

Alternative

OpenAI API

Broader model ecosystem with 126 endpoints spanning text, images, audio, and embeddings

Choose OpenAI when you need image generation, audio transcription, embeddings, or the widest range of model capabilities beyond text generation

Alternative

Cohere API

Enterprise LLM with native embedding and reranking for RAG pipelines

Choose Cohere when you specifically need embedding generation and document reranking in a unified API for search-focused applications

Alternative

Mistral AI API

Open-weight European models with competitive pricing

Choose Mistral when you need EU data residency, open-weight model access, or lower cost inference for high-volume text tasks

Complementary

Groq API

Ultra-fast inference hardware for latency-sensitive LLM workloads

Use Groq alongside Anthropic when you need sub-second response times for smaller models, while reserving Claude for complex reasoning tasks that benefit from larger context

FAQs

Specific to using Anthropic API API through Jentic.

Why is there no official OpenAPI spec for Anthropic API?

Anthropic does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call Anthropic API via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.

What authentication does the Anthropic API use?

The Anthropic API uses an API key passed in the x-api-key header. You also need to include an anthropic-version header (e.g., '2024-10-22') specifying the API version. Through Jentic, your Anthropic API key is stored encrypted in the MAXsystem vault and agents receive scoped access tokens without the raw key entering their context.

Can I process large documents with Claude's 200K context window?

Yes. The POST /v1/messages endpoint accepts messages with up to 200K tokens of combined input. You can send entire legal contracts, codebases, or research papers in a single request without chunking. Use POST /v1/messages/count_tokens first to verify your document fits within the window before incurring generation costs.

What are the rate limits for the Anthropic API?

Rate limits vary by tier. Tier 1 accounts get 50 requests per minute and 40,000 input tokens per minute. Higher tiers scale to 4,000 RPM and 400,000 input tokens per minute. The API returns 429 status codes with retry-after headers when limits are reached. Batch endpoints have separate, higher limits for async workloads.

How do I send a message to Claude through Jentic?

Search Jentic for 'send a message to Claude for reasoning', which returns the POST /v1/messages operation schema. The schema specifies required fields: model (e.g., claude-sonnet-4-20250514), messages array with role and content, and max_tokens. Execute the call through Jentic's SDK with pip install jentic. The x-api-key header is handled automatically by the vault.

What is the difference between the Messages API and the batch endpoint?

POST /v1/messages returns a response synchronously within seconds for real-time interactions. POST /v1/messages/batches accepts an array of message requests and processes them asynchronously — you poll for status and download results when ready. Batches offer cost savings and higher throughput limits but are not suitable for interactive conversations.