MCP tools on the API

Add one mcp tool per server. Fields: server_label (required, unique), server_url (required, HTTPS), authorization (sent as the bearer token), headers, server_description, allowed_tools (a list of names, or {"tool_names": [...], "read_only": true}), require_approval (always, never, or {"always"|"never": {"tool_names": [...]}}; default always) and defer_loading. connector_id and tunnel_id are not supported.

• The response contains mcp_list_tools, mcp_call and, when approval is needed, mcp_approval_request items. To answer one, send the whole input again with that mcp_approval_request item followed by an mcp_approval_response item (approval_request_id, approve: true|false, optional reason). Approvals expire after one hour; at most 8 per request.
• The API is stateless: send the mcp tool definitions again on every request; earlier mcp_list_tools items in the input spare a second listing.

curl "https://api.vani.ai/v1/responses" \
  -H "Authorization: Bearer $VANI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-6-sol",
    "store": false,
    "input": "Which transports does the MCP spec define?",
    "tools": [{
      "type": "mcp",
      "server_label": "deepwiki",
      "server_url": "https://mcp.deepwiki.com/mcp",
      "require_approval": "never"
    }]
  }'

Send mcp_servers (each {"type": "url", "url", "name", "authorization_token"}) with the anthropic-beta header mcp-client-2025-11-20, and reference every server from tools with one {"type": "mcp_toolset", "mcp_server_name": …}. A toolset may set default_config: {"enabled": false} and per-tool configs to allow only some tools.

• mcp-client-2026-09-15 also returns mcp_tool_listing blocks.
• The older mcp-client-2025-04-04 is accepted with its own shape: no mcp_toolset; each server may carry tool_configuration: {"enabled", "allowed_tools"}.
• The answer contains mcp_tool_use and mcp_tool_result blocks in order with the text. Calls run without an approval step.

curl "https://api.vani.ai/v1/messages" \
  -H "x-api-key: $VANI_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "anthropic-beta: mcp-client-2025-11-20" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-sonnet-5.5",
    "max_tokens": 1024,
    "messages": [{"role": "user", "content": "Which transports does the MCP spec define?"}],
    "mcp_servers": [{"type": "url", "url": "https://mcp.deepwiki.com/mcp", "name": "deepwiki"}],
    "tools": [{"type": "mcp_toolset", "mcp_server_name": "deepwiki"}]
  }'

• Up to 5 servers per request. URLs must be public HTTPS; private networks, localhost and a list of blocked hosts are refused before any connection.
• Tokens and headers you send are used for that request only and never logged or stored.
• Tool results are untrusted text: the model is told so. Every model turn of the loop is billed like any other request; MCP calls themselves are free.
• Chat Completions has no MCP field: use client-side function tools there.