Agent-ready OpenAPI document · curated by JenticAI/MLLanguage ModelsapiKey11 EndpointsREST
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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.
Use for: I need to send a message to Claude for complex reasoning, I want to count tokens in my prompt before sending it, List all available Claude models and their context limits, Check whether my message batch has finished processing
Not supported: Does not handle image generation, audio processing, embeddings, or vector storage - use for text generation, reasoning, and analysis only.
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.
Install Jentic One Beta
Connect the Anthropic API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Anthropic API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fanthropic.com%2Fanthropic-api" | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fanthropic.com%2Fanthropic-api" | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Anthropic 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
Cancel in-progress batch jobs to manage resource usage
Retrieve batch results as downloadable output once processing completes
Use Cases
Patterns agents use Anthropic 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
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
Jentic AI Readiness Score
This API is usable in Jentic One now. Its AI-readiness score against Jentic's framework shows where it stands today and where improvements would make it even easier for agents to use.
A
Anthropic API
- Foundational (C+)60/100
46
Foundational Compliance64
Developer Experience & Jentic Compatibility48
AI-Readiness & Agent Experience94
Agent Usability50
Security100
AI DiscoverabilityPowered by JenticScoring Framework 1.0.0 | Scoring Engine 0.4.0
Show dimension breakdown
46
Foundational Compliance
Base layer of spec validity and structural soundness.
Grade: DSignals: 4
50%
Lint Results
Aggregated quality score from linter diagnostics, weighted by severity.
100%
Resolution Completeness
Percentage of `$ref` references that resolve successfully.
0%
Specification Validity
Checks whether the API description parses successfully and conforms to its declared specification (e.g., OpenAPI).
35%
Structural Integrity
Structural correctness score based on schema issues using logarithmic dampening.
64
Developer Experience & Jentic Compatibility
Clarity, completeness, and ingestion readiness for developers and tooling.
Grade: BSignals: 4
11%
Example Density
How richly the API is illustrated with examples.
93%
Example Validity
Percentage of examples that conform to their schemas.
50%
Response Coverage
Percentage of operations with complete response definitions (success, client error, server error).
100%
Tooling Readiness
Health of API ingestion, bundling, and resolution within Jentic pipelines.
48
AI-Readiness & Agent Experience
Semantic breadth, depth, and agent comprehension for AI systems.
Grade: D+Signals: 4
38%
Description Coverage
Coverage of descriptions across API elements.
0%
Error Standardization
Coverage of RFC 9457 Problem Details for error responses.
100%
OperationId Quality
Coverage, uniqueness, and casing consistency of operationIds for AI inference.
55%
Summary Coverage
Coverage of summaries across operations/tags/info.
94
Agent Usability
Functional utility, complexity comfort, and AI orchestration readiness.
Grade: A+Signals: 1
94%
Complexity Comfort
Agent comfort level based on API operational and structural complexity.
50
Security
Trust, risk posture, and security compliance.
Grade: C-Signals: 1
50%
Authentication Strength
Average quality of security schemes based on authentication method strength (weakest link for OAuth2).
100
AI Discoverability
Findability, semantic richness, and reasoning readiness.
Grade: A+Signals: 1
100%
Descriptive Richness
Clarity and depth of descriptions across API elements.
Score it yourself
Every API in the directory is allowlisted, so you can re-score it with no key required.
npx @jentic/api-scorecard-cli score <openapi-url>Why Jentic?
What agents get from Jentic-routed access to this vendor.
Setup
Wiring the Anthropic API by hand means setting the x-api-key and anthropic-version headers on every request and tracking batch job ids yourself. Through Jentic you install once, import the Anthropic API from the API Directory, store the API key once, and your agent calls it.
Permission scoping
The Anthropic API takes message content in the request body and exposes batch and model reads by id in the path, so scope the agent to the operations it needs, such as sending messages and counting tokens. You choose the operations it may call, so batch cancellation is not included unless you add it.
Credential isolation
Your Anthropic API key is stored once, encrypted, by your own Jentic One instance and injected with the required version header at execution time. It never enters the agent's prompt, logs, or context.
Intent-based discovery
Agents search Jentic by intent such as 'analyze a long document with Claude' or 'count tokens for a prompt', and Jentic returns the matching Anthropic operation with its input schema so the agent calls the right endpoint without browsing the reference docs.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Anthropic 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 with Jentic One, the self-hosted execution layer.
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 your Jentic One instance 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.
Can I limit what my agent is allowed to do with the Anthropic API?
Yes. Because you run Jentic One yourself, your own rules decide which Anthropic API operations and credentials the agent may use. You can scope it to just the operations it needs, such as sending messages via POST /v1/messages and counting tokens via POST /v1/messages/count_tokens, while leaving out batch creation and cancellation. If the agent has no rule granting an operation like cancelling a batch, it cannot call it.
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