Use Link Identity

Link identity

These commands are in beta and appear in link-cli identity --help without a preview flag. Use them when a service accepts Link attestations or signed user claims.

An AAT proves issuance by Link without disclosing user claims. A presentation discloses selected claims and proves possession of the credential's holder key for an audience and nonce. If the service requires both, send both headers.

Setup and handling

Use Link Agent Wallet v0.27.0 or later. Check link-cli --version; if older or missing, install or update with npm install -g @stripe/link-cli@latest. No LINK_IDENTITY_COMMANDS flag is needed. See wallet setup; reuse the create-payment-credential skill's authentication guidance.

• Identity commands are available through the CLI, not its MCP tools.
• Only request needs Link authentication. list, pop, and present use local files. Requests return paths and metadata; pop and present return proofs.
• Capture stdout with --format json, parse it programmatically with a JSON parser or jq, and pass the exact proof to the HTTP client or browser automation. Never manually transcribe, reconstruct, or re-encode tokens or presentations. Keep proofs, private keys, and claim values out of transcripts and logs; use restrictive permissions for handoff files.
• Cached identity files belong to the home directory. Changing --auth or logging in as another user does not switch the cached identity. Use separate home directories for different users.

Attestations

bashCopy code
# Inspect inventory.
link-cli identity attestations list --format json

# Refill only when needed. Count is required: 1–100.
link-cli identity attestations request --count 10 --format json

# Pop a token when ready to use it.
link-cli identity attestations pop --format json

Check errors and attestations. Only entries with storage: "pool" are available to pop; total_token_count also includes exports. Requests append to ~/.link-cli/identity/attestations/pool.json.

Example pop output:

jsonCopy code
{
  "issuer": "https://api.link.com",
  "token_key_id": "<issuer-key-id>",
  "token": "<token>",
  "authorization": "PrivateToken token=\"<token-with-header-padding>\""
}

Use authorization verbatim, including its scheme and quoting. pop removes the token locally; server reuse rules belong to the service. Keep the same AAT for retries tied to an existing interaction, and use a fresh one for a new service. Do not return popped tokens to the pool.

For agent-managed allocation, export a batch instead:

bashCopy code
link-cli identity attestations request --count 10 --output-file ./aats.json --format json

Use a new file outside ~/.link-cli/identity/attestations. Read its tokens array and each entry's authorization programmatically. Exported tokens never enter the CLI pool; the caller owns allocation, concurrency, and cleanup.

Credentials and presentations

bashCopy code
# Check errors, expired, expires_at, and claim_names.
link-cli identity credentials list --format json

# Request only if no usable credential exists for the intended user.
link-cli identity credentials request --format json

Issuance replaces ~/.link-cli/identity/credentials/current.json and creates or reuses ~/.link-cli/identity/holder-key.jwk. Keep both local. Choose claims with present:

bashCopy code
link-cli identity credentials present \
  --aud 'https://service.example' \
  --nonce '<nonce-from-challenge>' \
  --claim email \
  --format json

Use the service challenge's exact audience and nonce after checking that they belong to the intended service. All three options are required. Repeat --claim only for additional requested claims authorized by the user's task. Pass challenge values as individual process arguments or quote them safely in a shell.

Example output:

jsonCopy code
{"presentation":"<issuer-jwt>~<email-disclosure>~<key-binding-jwt>"}

present signs locally with the saved holder key and leaves the files unchanged. Send the presentation promptly. Reuse the underlying credential until expiry, but obtain a fresh challenge after a nonce is consumed or expires.

Send and recover

Set headers only for the intended endpoint. Preserve the challenged operation's method, body, session, interaction identifiers, and any required AAT. Avoid global browser headers or redirects that forward proofs to another origin. Report success only after the service accepts the request.

• ATTESTATION_POOL_EMPTY: request a batch, then pop a token.
• Errors in list: inspect the reported file/error instead of treating storage as empty.
• Unavailable claim: check claim_names; do not disclose extra claims or the raw credential.
• Missing or mismatched holder key: preserve the files and restore the correct key or explicitly obtain a new credential.
• Audience or nonce rejection: check the intended service and its current challenge before presenting again.