Fax for Agents

What Fax for Agents does

Fax for Agents exposes fax operations to MCP clients through the Fax for Agents service. Its toolset covers the full outbound workflow: prepare a document, retrieve its details, obtain a destination-specific quote, request approval when needed, queue an approved fax, and inspect its status. It also supports inbound workflows for listing received faxes, reading their contents, and extracting structured fields with citations.

The server includes tools for account capabilities, balance checks, cancellation, human review, and policy handling. It also publishes a guide as MCP resources and provides two prompts: send_a_fax for an outbound sequence and handle_received_fax for processing an inbox item.

How it works

You can connect in two ways. The hosted endpoint is https://mcp.faxforagents.com/mcp/ and accepts an API key on each request through bearer authentication or X-API-Key. The npm package runs the same tools locally over stdio, using FAXFORAGENTS_API_KEY from the process environment. A Docker image can also run the stdio server with interactive input.

Test keys use a sandbox provider and do not contact a carrier or incur a charge. Live keys use the carrier and the account's prepaid wallet. Without a key, the server can still expose its tools, prompts, and guide resources; authenticated operations return an invalid-token result.

Tool results contain text plus structured fields such as ok, message, and error_code. An unsuccessful result is represented as a normal tool response with a remediation message. Carrier-provided, customer-supplied, and fax-received strings are marked as untrusted data and should not be treated as instructions or reused as destinations or approval identifiers.

Setup and configuration

Install and run the local package with Node.js 20 or later:

npx -y faxforagents-mcp

Set FAXFORAGENTS_API_KEY in the client environment. Keys are created through the Fax for Agents dashboard. The repository also supports installation directly from GitHub and provides a Dockerfile for stdio deployments.

For hosted connections, configure the endpoint with an Authorization: Bearer <key> header. The trailing slash in the hosted URL is significant. The documented client configurations include Claude Code, Claude Desktop, Cursor, Codex, and n8n.

Tools and capabilities

The 15 tools are:

• get_guide — Read the manual or a selected section without authentication.
• get_fax_capabilities — Inspect routes, formats, limits, pricing, and key scopes.
• prepare_fax — Create a document from text, Markdown, HTML, or an uploaded PDF, PNG, JPG, or TIFF.
• get_document — Retrieve page count, SHA-256, warnings, and signed preview URLs.
• quote_fax — Get a ten-minute quote, policy result, and approval requirement.
• send_approved_fax — Queue a quoted fax using an approval or policy.
• get_fax_status and list_faxes — Inspect attempts, states, and delivery evidence.
• get_fax_balance — View available and held funds.
• cancel_fax — Cancel a queued fax, with best-effort cancellation after sending begins.
• request_human_review and get_review_status — Request and monitor human approval or assistance.
• list_inbox and read_inbound_fax — Browse received-fax metadata and contents.
• extract_fax_data — OCR a fax or document and return schema fields with citations.

Delivery evidence comes from the carrier and can include a remote station ID, page count, timestamps, and provider reference. It indicates what the carrier reported, not proof that the recipient accepted the fax.