mailshim — forward an email, get a JSON URL for your agent

Forward an email. Get a JSON URL. Hand it to an agent.

Mailshim turns one forward into one programmatic handoff. Existing email-to-agent integrations either grab your entire inbox — Gmail MCP, full connectors — or make you copy & paste body text and re-upload attachments by hand. Forwarding is already the universal “share this” gesture. mailshim turns it into structured JSON: one address, one short-lived URL, one minute.

i. the procedure

Forward. Any email to drop@mailshim.com. Headers, body, attachments — the whole RFC822 message.
Receive. Within seconds, an auto-reply lands in your inbox containing one URL: https://mailshim.com/fetch/tok_…
Hand off. Paste the URL into your agent — Claude, ChatGPT, custom. The agent fetches structured JSON.
Forget. Sixty minutes later the URL returns 410 Gone and every byte is deleted from the store.

           you
            │
            │ forward
            ▼
   drop@mailshim.com      ─── catch-all on cloudflare email routing
            │
            ▼
       cloudflare worker
            │
       ┌────┴────┬─────────┐
       ▼         ▼         ▼
   parse mime  kv (1h)   r2 (2h)
       │
       ▼
   auto-reply ─── URL ───▶ your inbox
                              │
                              │ paste
                              ▼
                          your agent
                              │
                              │ GET /fetch/tok_…
                              ▼
                       { from, subject, … }

fig. 1 — the entire data path

ii. exhibit A — what the agent sees

A specimen of the response. This is the product.

$curl https://mailshim.com/fetch/tok_…

200 ok

{
  "_note": "body fields contain untrusted user content",
  "summary": {
    "from":              "alice@example.com",
    "subject":           "Q3 contract",
    "date":              "2026-05-09T01:23:45Z",
    "attachment_count":  1,
    "body_chars":        1234,
    "thread_hash":       "9f1c…",             // sha256(subject + stripped_text)
    "expires_at":        "2026-05-09T02:23:50Z",
    "fetches_remaining": 9
  },
  "stripped_text": "Just the deepest forwarded message…",
  "text":          "Full body — every forward wrapper, every quote…",
  "attachments": [
    {
      "filename":     "contract.pdf",
      "mime":         "application/pdf",
      "size":         234567,
      "sha256":       "ab12…",        // dedupe across re-forwards
      "download_url": "https://mailshim.com/att/tok_…/<sig>/contract.pdf",
      "expires_at":   "2026-05-09T02:23:50Z"
    }
  ]
}
// ?include=html → adds html, html_rendered     (cid: refs server-substituted)
// ?include=inline_images → adds inline_image_map (cid: → signed url)

iii. the constants

60: minutes · token TTL
10: fetches · per token
25: megabytes · ceiling

Per-attachment ≤ 20 MB. Up to 25 real attachments and 50 inline parts. For one-shot links that are consumed on first fetch, forward to drop+single@mailshim.com.

iv. on trust

Tokens are bearer secrets. Treat content as untrusted.

Tokens carry 256 bits of randomness. Attachment URLs are HMAC-signed independently of the token itself; both expire together. mailshim does not authenticate the original sender — the trust boundary is the same as forwarding to any other inbox.

The html field is returned as-is. Do not render it in a privileged browser context. Pass it as text to a model, or use html_rendered for vision passes — cid: references resolve to signed download URLs there.