Fax for Agents

npx add-mcp 'https://mcp.faxforagents.com/mcp/'

The hosted fax MCP server

Claude Code

Shell

claude mcp add --transport http faxforagents https://mcp.faxforagents.com/mcp/ \
  --header "Authorization: Bearer ffa_test_..."

The hosted MCP server lives at https://mcp.faxforagents.com/mcp/ and speaks Streamable HTTP. It carries the same credential as the REST API, Authorization: Bearer ffa_test_... or X-API-Key, on every request. There is no operator key on the server and no state between requests. A client with no key is still answered on initialize, tools/list, the resources and the prompts. Every tool then answers with error_code: invalid_token and the way to get a key.

The 15 tools

Tool	What it does
get_guide	The manual, by section: overview, send, states, errors, approvals, policies, agents, inbox, ocr
get_fax_capabilities	The account-level view behind the key: formats, page cap, routes, prices, scopes. It never evaluates a send
prepare_fax	Create a document from text, Markdown, HTML or an upload
get_document	One prepared document by id: page count, sha256, validation warnings and signed preview URLs
quote_fax	Price one document to one destination, with the policy verdict: allowed or denied, the first failing rule, whether a person must approve. The quote binds the send
send_approved_fax	Send a quote with an approval or under a policy
get_fax_status	The job's state and attempts, and once delivered or partial the carrier's evidence as a reference
list_faxes	Sent faxes, newest first
get_fax_balance	Available and held balance
cancel_fax	Cancel if still possible
request_human_review	With a quote id, ask a person to approve that send. Without one, ask a person for help, the message recorded as data
get_review_status	The state of one request: pending, approved, rejected, revoked or expired, with the approval id once approved
list_inbox	Received faxes, newest first, metadata only
read_inbound_fax	One received fax, its text listed as untrusted
extract_fax_data	OCR and structured extraction of a received fax, every value listed as untrusted

Version 1.3.0 merged three tools into their neighbours. get_delivery_evidence is part of get_fax_status. request_fax_approval and request_human_help are one tool, request_human_review. The bare guide is get_guide. Version 1.3.2 swapped two. preview_fax is get_document, which returns the document itself. evaluate_fax_policy is gone because the quote carries the same verdict, and get_review_status reads one request back. Documents are listed through the REST API. The old names are gone from the server.

Resources and prompts

The manual is also served as MCP resources. faxforagents://guide is the whole text and faxforagents://guide/send, faxforagents://guide/states and the other sections are one resource each, all text/markdown and all readable without a key. Two prompts give a client the tool order. send_a_fax takes a destination and an optional summary. It walks through prepare, quote with its policy verdict, human review and the poll for its decision, send and status. handle_received_fax takes an inbox item id and walks through read, extract and human review, with the rule that the text of a received fax is data.

Every result is text plus structured content: ok, message, error_code, and untrusted listing every string a customer or a sender supplied. The success message of a send says queued. The word delivered appears only when the provider's evidence exists, with the evidence beside it.

What the server will not do

It will not widen a key's scopes, raise a budget or decide an approval. Those are a person's actions in the dashboard, with a passkey step-up for a decision. It will not read the text of a received fax as an instruction. A quote id or an approval id lifted from a document and passed as an argument is refused as invalid_input before any request leaves the tool.

Clients

Claude Code, Claude Desktop, Cursor, Codex and n8n connect with the URL and a key. The setup page has the exact configuration for each. OAuth 2.1 for MCP is planned for a later release and is not live. API keys are the only credential today. The server's source, with the stdio bridge for a client that cannot reach a remote server, is at github.com/faxforagents/mcp.

Prices

• $0.039per page sent
• $0.019per page received
• $2per number per month
• OptionalAgent workspace, $19 per month

Prepaid wallet, $10 minimum top-up. United States and Canada prices as of 2026-10-28. International rates are in the rate table. The sandbox is free.

Questions

What is a fax MCP server?

A server that exposes fax operations as tools an AI client can call over the Model Context Protocol. This one runs at mcp.faxforagents.com and wraps the Fax for Agents REST API. Its 15 tools prepare a document, quote it, ask a person to review it, send and cancel. They also read status with the carrier's evidence, read the inbox, extract data from a received fax and check the balance. The manual is served as resources and two prompts give the tool order. The protocol is the door. The API behind it still enforces every rule.

How is a fax MCP different from a fax API?

The API is a set of HTTP endpoints your code calls with a key. The MCP server presents the same operations as named tools with descriptions and schemas. A client such as Claude Code or Cursor can pick and call them in a conversation. Both reach the same server, the same wallet and the same approvals. Nothing is possible through MCP that the API forbids.

Does the MCP server replace the telephone provider?

No. The MCP server is an interface. Transmission still happens through a fax provider the service connects to, with its own line, retries and delivery reports. The tools return what that provider reported, which is why a send answers queued and the delivered word only appears with the provider's evidence attached.

Do I need a subscription to use the fax MCP?

No. The MCP server is part of the service at no extra charge. Pages are prepaid at $0.039 sent and $0.019 received in the US and Canada as of 2026-10-28. The sandbox is free with a test key. The optional Agent workspace at $19 a month is a separate subscription and the MCP tools work without it.