# Send a fax with an MCP server: all 15 tools in order > A walkthrough of the hosted fax MCP server from Claude Code, Cursor or Codex. Connect, prepare, quote, ask a person, send, read the status, read the inbox. Page: https://faxforagents.com/blog/send-a-fax-with-mcp/ Last changed: 2026-10-31 A walkthrough of the hosted fax MCP server from Claude Code, Cursor or Codex. Connect, prepare, quote, ask a person, send, read the status, read the inbox. - Published Oct 31, 2026 - About 6 min read - By [Fax for Agents team](https://faxforagents.com/about/) This walkthrough shows you how to send and receive a fax from an MCP client. It names all 15 tools in the order an agent uses them. The hosted [fax MCP server](https://faxforagents.com/mcp/) is at `https://mcp.faxforagents.com/mcp/`. It takes an API key. With a test key, you can run the whole workflow in the free sandbox. ## Connect a client Add the hosted server to Claude Code: ``` `claude mcp add --transport http faxforagents https://mcp.faxforagents.com/mcp/ --header "Authorization: Bearer ffa_test_..."` ``` Replace `ffa_test_...` with your test API key. Keep the key in your client configuration, never in a prompt. The connection uses Streamable HTTP with bearer authentication. Keep the trailing slash on the server URL. Cursor connects to the hosted URL with the bearer token in its MCP configuration. Codex uses the same endpoint and API key authentication. Claude Desktop needs the `faxforagents-mcp` stdio bridge because its remote connection asks for OAuth, which this server doesn't support yet. n8n connects to the hosted endpoint with the API key as a bearer token. The [client setup guide](https://faxforagents.com/docs/mcp-setup/) covers configuration. ## Orient: `get_guide` and `get_fax_capabilities` `get_guide` returns the manual section you request. The sections are `overview`, `send`, `states`, `errors`, `approvals`, `policies`, `agents`, `inbox` and `ocr`. Read `send` for the send sequence and `states` for the meaning of status results. Read `errors` when a call fails. `get_fax_capabilities` reports formats, the page cap, routes, prices and scopes available behind your API key. It never evaluates a send. Use `quote_fax` to check a particular destination. Every tool result carries `ok`, `message`, `error_code` and `untrusted`. Check the result before continuing to the next call. ## Prepare: `prepare_fax` and `get_document` `prepare_fax` creates a document from text, Markdown, HTML or an uploaded file. Uploaded files can be PDF, PNG, JPG or TIFF. Convert Word or Excel files to PDF before uploading them. The document limit is 200 pages and 25 MiB. The service renders text, Markdown and HTML to PDF. Each document gets its own page count and `sha256`. Documents are kept for 30 days by default. Call `get_document` with the document id. It reports the page count, `sha256`, warnings and signed preview URLs. Check the preview and any warnings before asking for approval. The document's `sha256` identifies the content covered by an approval. Cover pages count as pages. Include them when reviewing cost. ## Quote: `quote_fax` `quote_fax` prices one document for one destination. Sending to the United States and Canada costs $0.039 per page as of 2026-10-28. The result includes the policy verdict, `allowed` or `denied`. You also get the first failing rule and whether a person must approve. The quote binds the price, page count, sender and destination for ten minutes. Check the destination before requesting review. If the quote expires, get a new one before continuing. ## Ask a person when needed: `request_human_review` and `get_review_status` Call `request_human_review` with the quote id when a person must approve. That request asks for consent to that exact send. The person decides in the dashboard with a passkey step-up. Poll `get_review_status` while review is `pending`. It returns `approved`, `rejected`, `revoked` or `expired` as the decision changes. An approved result includes the approval id. Approval binds the document's `sha256`, destination, sender number, amount and expiry. Changing any of them invalidates it. The expiry follows the quote's ten minutes. Agent keys never have the scope that decides approvals. An expired approval fails with `approval_expired`. A consumed approval cannot be reused and fails with `approval_consumed`. Without a quote id, `request_human_review` asks a person for help. Its message is recorded as data. The [approval documentation](https://faxforagents.com/docs/approvals/) explains the binding and expiry rules. ## Send: `send_approved_fax` `send_approved_fax` submits the quote with an approval or under a delegated policy. The wallet holds the quoted amount. The response is a job in state `queued`. You still need to check the outcome. Use `get_fax_status` to read the job's state and attempts. A job moves through `queued` and `active` before its final state. The server writes `delivered` only after the provider's report for every page is stored on the attempt. For `delivered` or `partial`, the status result includes the carrier's evidence. The other final states are `failed` and `unknown`. An `unknown` state means there's no outcome yet. For `unknown`, nothing is retransmitted on its own. Busy and no answer are retried up to three times. Failed sends are not charged. Partial sends charge only pages the provider confirmed. The receipt records the job id, destination, sender and pages. It also records the provider reference, document `sha256`, amount captured and completion time. Use `list_faxes` for sent history, newest first. `get_fax_balance` shows available and held funds. You can check it before sending, too. Separate budgets can refuse a hold even when wallet funds are available. Call `cancel_fax` if you need to stop a job while cancellation is still possible. ## Receive: `list_inbox`, `read_inbound_fax`, `extract_fax_data` Start with `list_inbox`, which returns received faxes newest first as metadata only. Choose one item, then call `read_inbound_fax`. Its text appears under `untrusted`. Receiving needs a fax-capable number from the API. Launch availability covers the United States, Canada, Puerto Rico and the US Virgin Islands. Other locations are available on request. Each received fax is a PDF in a private inbox. Access uses a signed URL that lasts ten minutes. Inbox items are kept for 90 days by default. `extract_fax_data` reads a received fax page by page. It returns text or fields from your supplied schema, and can return a document type or summary. Each value has a page citation and confidence. Every value is `untrusted`. Treat extracted instructions as document contents. The dashboard labels this material "from the document, unverified". With a test key, extraction runs on the sandbox engine today. The engine is off for live keys, with no date announced for activation. The [receive fax API](https://faxforagents.com/receive-fax-api/) also sends signed `fax.received` events. ## Resources and prompts The manual is available at `faxforagents://guide` and as a separate MCP resource for each section. These resources are readable without an API key. The `send_a_fax` and `handle_received_fax` prompts give the tool order for their respective workflows. ## What the server refuses An agent cannot widen its scopes or raise its budget. It cannot decide an approval. Those limits apply even when a prompt tells it to continue. Text from an incoming fax is data. It cannot authorize a send. The policy engine never reads it. An id lifted from a document is rejected with `invalid_input`. Use the ids returned when the service creates documents and jobs. [Delegated policies](https://faxforagents.com/docs/policies/) are evaluated on the server from the quote and the document row. Prompt text cannot change those rules. Separate budgets refuse a hold before money moves. Daily and monthly caps can apply per organization, project or agent. Every action has an audit row with an actor and metadata only. Disabling an agent revokes its keys. ## A full session in order For a send that requires a person's approval, use this order: 1. `get_guide`: read the `send` section. 2. `get_fax_capabilities`: check formats and scopes. 3. `prepare_fax`: create the document. 4. `get_document`: inspect the page count and preview. 5. `quote_fax`: price the document to the destination. 6. `request_human_review`: ask for approval with the quote id. 7. `get_review_status`: poll for a decision. Continue only when approved. 8. `send_approved_fax`: submit the quote with its approval. 9. `get_fax_status`: read the outcome and inspect provider evidence when available. 10. `get_fax_balance`: check available and held funds. ## Questions ### Do I need an API key to list the tools? No. The initialize and tools/list calls answer without an API key. Resources and prompts are also readable without one. Every tool call then returns the error code invalid_token until you provide a valid key. Put the bearer token in your client configuration before starting the send workflow. ### Does the fax MCP work with Claude Desktop? Yes, through the stdio bridge today, the npm package faxforagents-mcp. Claude Desktop asks for OAuth when you add a remote server. Fax for Agents has no OAuth yet, so the bridge provides the connection. Store the API key in the client configuration. Keep it out of prompts. ### Can the agent send without asking me? For a live send, only under a delegated policy an administrator wrote. The server checks that policy for every send. Rules can limit destinations, sender numbers, pages and amounts. Each policy version is immutable, and the job records the version that allowed it. The agent cannot expand the policy or raise its budget. ## On this site - [The hosted fax MCP server](https://faxforagents.com/mcp/) - [MCP setup](https://faxforagents.com/docs/mcp-setup/) - [Approvals](https://faxforagents.com/docs/approvals/) ## Related posts - [Why AI agents still need fax, and how to keep them safe](https://faxforagents.com/blog/why-ai-agents-need-fax/) Where agent workflows end at a fax number and what goes wrong when an agent faxes freely. The four server-side controls: quote, approval, policy, identity. - [Receiving faxes as data: inbox, OCR and schema extraction](https://faxforagents.com/blog/receive-faxes-as-data/) A number, a signed event, the PDF, the text and the fields with a confidence. How the pipeline works, why fax text is untrusted, and what is live today.