Create a message

Create a message

Returns Claude's next message for a prompt or conversation, such as a drafted email or a label for a record.

Note: The API call needs the anthropic-version: 2023-06-01 header alongside the key, and max_tokens is required in the body.

Set up

Use the first option your agent supports.

CLI (official)

Install the command and sign in with it, then confirm it runs.

curl -fsSL https://claude.ai/install.sh | bash
claude --version

Run claude -p.

API (official)

• Base URL: https://api.anthropic.com
• Endpoint: POST /v1/messages
• Auth: send the header x-api-key: $ANTHROPIC_API_KEY
• Get a key: https://platform.claude.com/settings/keys
• Docs: https://platform.claude.com/docs/en/api/overview

Before anything else, confirm access with the cheapest read-only call, like a list or a search. Never send or change anything to test access.

Rules

• Ask the user before anything that sends messages, costs money, or changes data, and say how many records it touches. One approval covers a batch the user has seen.
• Never print API keys.