MCP electronic signatures with Atlas

Model Context Protocol (MCP) lets an AI client call tools on a remote server. Atlas runs an MCP server at https://atlaswork.ai/api/mcp with ten tools that cover the full signing lifecycle.

This is not a sidebar that opens another vendor in an iframe. The agent creates envelopes, polls status, and reminds signers inside the thread.

> Share: "Ten MCP tools cover signing from upload through extract, with review before email on new docs."

Why MCP for e-sign

REST APIs are fine when your code owns the flow. MCP is better when the user stays in chat. The agent can upload a document, request an upload link for local files, list templates, check status, remind a signer, or void an envelope without you writing orchestration glue.

Atlas is opinionated about one rule: agents prepare, humans send on ad-hoc uploads. send_contract_for_review returns a review_url. Signers get email only after someone clicks Send on that page.

Trusted templates are the exception. send_contract_from_template can auto-send when legal already approved the pinned fields.

Connect by client

Claude and ChatGPT use OAuth. Add Atlas as a custom connector, sign in when prompted, start a new chat. See Claude MCP setup for the one-click install link.

Cursor and Claude Code use a Bearer API key in your MCP config file. Copy the snippet from Cursor MCP setup and replace YOUR_API_KEY with a key from dashboard settings.

Full overview at /mcp.

Tool map

Legacy names like send_contract still route to send_contract_for_review.

Local files in Claude Desktop

Claude cannot pass a dragged PDF to Atlas. Ask the agent for an upload link instead:

1. Prompt with signer emails and ask Atlas to start an upload session.
2. Open the link and upload your PDF or DOCX.
3. Say "done" in chat so the agent calls complete_upload_session.
4. Open the review_url and click Send.

ChatGPT can often accept an attachment in chat. Every other client should use the upload session path.

Idempotency

Write tools auto-stamp an Idempotency-Key if the client does not send one. Retries within a 60-second bucket dedupe on the server.

REST create uses the same Idempotency-Key header pattern with a 24-hour window. Agents that retry aggressively will not double-charge sends when the first call actually succeeded.

When to use REST instead

MCP shines in chat. REST shines in cron jobs, queue workers, and multi-step backend flows. Many teams use both: MCP for operator chat, REST for production traffic.

Platform child accounts are REST-only in v1. Pass Atlas-Account on each call when you embed signing in a SaaS product.

Free tier

All ten MCP tools work on the free tier. You get five envelope sends. Drafts and field detection do not consume credits. That is enough to demo Claude or Cursor to your team before you buy a credit pack. Sign up to start.

Webhooks from chat-driven sends

Pass webhook_url in tool arguments when the agent creates an envelope. Your backend can wake up on envelope.signed even if the human clicked Send from review on a laptop. Verify signatures the same way as REST creates.

Status polling pattern

After a human clicks Send on review, ask the agent to check_signing_status every few minutes or wire webhook_url at create. The tool returns next_signer_email and a sign_url you can forward internally while you wait. When signed_count equals total, call get_envelope for download links and extract_contract_data if you need structured fields from the signed PDF.

Org and API keys

OAuth connectors bind to your Atlas user. Cursor and Claude Code use org API keys from Settings. Rotate keys if a laptop with mcp.json is lost. Keys never belong in chat transcripts.

FAQ

Can MCP bypass review? Not on new uploads. Templates and auto-send on REST are for proven shapes.

Does MCP work with DOCX? Yes. Upload PDF or DOCX. Atlas converts DOCX to PDF at ingest.

Where are recipes? See Connect guide and send NDA from Claude.

How does Atlas compare to DocuSign for agents? DocuSign has mature REST. Atlas adds native MCP. See DocuSign comparison.

Docs and examples

• Connect guide
• Send NDA from Claude recipe
• How to send a contract from Claude
• MCP overview