Private means link-locked.

What is public

The public link shows the card fields agents need: status, boundaries, allowed actions, ask-first rules, public resources, JSON, Markdown, schemas, and the public request key.

What is private

The private link opens locked notes and inbox notes. Signing in proves account identity, but it does not unlock locked content. If you lose the private link, locked content is unrecoverable.

Creating cards

• Public-only cards need no private link. Agents read the public URL only.
• Cards with a private note or inbox need a private link at creation. Copy it from the edit page while your browser still has the key — we cannot restore it later.
• Inbox and private-note sections cannot be added after the card is created in v1.

How to verify

1. 1. Open browser DevTools, then open the Network tab.
2. 2. Create or edit a card with a unique private note, for example purple elephant private test.
3. 3. Inspect the request to /api/cards.
4. 4. Confirm the private phrase is not present in the request body.
5. 5. Confirm the request contains only the encrypted private blob: ciphertext, nonce, and algorithm.
6. 6. Open the public link and confirm locked content is unavailable; open the private link and confirm it decrypts in the browser.

Stored private format

The server accepts one encrypted shape for private card fields. The secret key is not in this object; it is carried by the private link fragment as #key=....

{
  "encryptedPrivateBlob": {
    "algorithm": "aes-gcm-v1",
    "ciphertext": "base64url(AES-GCM ciphertext and tag)",
    "nonce": "base64url(12 random bytes)"
  }
}