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AgentSign

A signing primitive, not a signing suite. Drop a file or POST it. A human Finishes. An agent can Attest. You get a sealed PDF and an audit trail.

• Production: https://agentsign.co
• Repo: https://github.com/mar3co/AgentSign
• API reference: /openapi.json, /llms.txt, product docs at /docs

The one rule

Keys authenticate the caller; they never sign for a human. There is no sign API or MCP tool. Humans Finish. Agents Attest.

What it does today

• Send a document as a PDF, a Word file (.docx, converted to PDF server-side), or markdown (rendered to a clean PDF, {{sig}} tags become fields). Web, REST, and MCP.
• Fields: {{sig}}-style tags in the document, drag-and-drop placement in the send editor, AcroForm import, and AI field detection for PDFs (POST /v1/detect-fields).
• Sign: signers get an email link and finish at /s/:token with no account.
• Attest: named agents (sign_agent_… keys) attach cryptographic receipts; OAuth agent sends are held for the account owner's emailed confirmation by default.
• Verify: POST /v1/verify checks our seal on any PDF, unauthenticated.

Packaging

Free (login optional): 7 days to sign, 7-day shredder after the keep window, ~20 sends per 30 days. Pro $19/mo: 1-year keep, branding, templates, team, 10 named agents. Self-host with SELF_HOST=1 gets Pro extras forever. Apache-2.0.

Stack

Vercel (Next.js App Router, Node runtime) + Supabase (Postgres, Auth, Storage) + Resend (mail) + Stripe Checkout (Pro). UI is shadcn/ui on Base UI with Tailwind.

More pages

• Send-Pipeline: formats, fields, and what happens between upload and sealed PDF
• Development: local setup, offline mode, tests, conventions

Deeper design docs live in the repo under docs/; specs and plans ride with the code and are reviewed in PRs.