Bankr dynamic key vending

Some partner credentials should never sit in a vault as a static secret. Bankr key vending is a secret engine: you store one partner key server-side, and 1Claw mints scoped, TTL-bound user keys on demand.

• The partner key (bk_ptr_) is held server-side as BANKR_PARTNER_KEY.
• The Vault issues short-lived bk_usr_ keys scoped to a single agent.
• Recommended TTL is 5-15 minutes; the agent default is 15 minutes and the hard maximum is 24 hours.
• This is preferred over storing a Bankr credential with put_secret.

1. 1

   Grant the agent leasing rights with a policy on its Bankr path.

   bash Copy

   curl -s -X POST https://api.1claw.co/v1/vaults/$AGENT_KEYS_VAULT/policies \
     -H "Authorization: Bearer $ONECLAW_TOKEN" \
     -H "Content-Type: application/json" \
     -d '{
       "principal_type": "agent", "principal_id": "'$AGENT_ID'",
       "path_pattern": "agents/'$AGENT_ID'/bankr/*",
       "permissions": ["read"]
     }'

2. 2

   Lease a key with a short TTL.

   bash Copy

   curl -s -X POST https://api.1claw.co/v1/agents/$AGENT_ID/bankr-keys \
     -H "Authorization: Bearer $AGENT_TOKEN" \
     -H "Content-Type: application/json" \
     -d '{"ttl_seconds": 600}'

3. 3

   Note what comes back to an agent caller: metadata, but no api_key field.

   json Copy

   { "lease_id": "...", "expires_at": "...", "scope": "bankr:wallet" }

4. 4

   List and revoke active leases.

   bash Copy

   curl -s https://api.1claw.co/v1/agents/$AGENT_ID/bankr-keys \
     -H "Authorization: Bearer $ONECLAW_TOKEN"

The pattern generalises: when a credential can be minted on demand, leasing beats storing. There is nothing long-lived to leak, and expiry is the default rather than something you have to remember to do.

Where this goes wrong in practice. Vending removes the static credential and introduces a lifecycle, which is a smaller problem that still has to be managed.

• TTLs drift upward. Each extension is justified by one long job, and the ceiling becomes the default, at which point leasing has recreated the static key it replaced.
• Leases are never revoked. Expiry eventually handles it, but an incident needs immediate revocation, and teams discover the endpoint exists while trying to use it.
• The lease response is logged. It omits api_key by design, and a service that logs whole responses can still capture surrounding metadata useful to an attacker.
• The path policy is written broadly. Vending is deny-by-default and a glob written as agents/** grants far more than the one agent's Bankr path.