ADDRESS BOOK MCP FOR AI AGENTS
OnceAsk gives compatible assistants a current address layer: identify the person, determine whether their mailing address is usable now, and request an update when it is not.
Email, calendar, CRM, and contact tools can identify who a user means. OnceAsk adds the mailing-address layer: resolve that known person against the user's current OnceAsk relationships instead of treating an old address field as truth.
If an address is missing, outdated, or not yet authorized, the MCP response provides a declared next action. The agent can trigger a recipient confirmation flow instead of guessing or asking the model to invent a destination.
Once a destination is authorized, compatible agents can use supported fulfillment actions for cards, gifts, and other physical delivery workflows without making raw street-address retrieval the default primitive.
HOW IT WORKS
Add the remote MCP endpoint at https://onceask.com/_api/mcp. Consumer clients can connect through OnceAsk OAuth; developer integrations can use scoped API credentials.
Call resolve_delivery with the person the user means. OnceAsk returns a structured state such as authorized, permission_required, address_update_required, ambiguous, or not_found.
Proceed when authorized, ask the user to disambiguate when needed, or call request_delivery_permission so the recipient can confirm a missing or stale mailing address.
BUILT FOR PEOPLE + AI
OnceAsk gives people one current address to maintain and gives compatible assistants a permissioned way to resolve or request the delivery information they need.
QUESTIONS
An address book MCP is a Model Context Protocol server that gives compatible AI clients structured tools for working with contact or address-book data. OnceAsk focuses specifically on current mailing addresses, recipient confirmation, permission, and physical-delivery workflows.
The remote OnceAsk MCP endpoint is https://onceask.com/_api/mcp. OnceAsk is also registered in the official Model Context Protocol Registry as io.github.rsb6061/onceask.
Yes. OnceAsk supports contact-oriented tools, but its main agent use case is resolving a known person to a current mailing-address state and requesting an update when the address is missing, stale, or not yet authorized.
Yes. When resolution indicates that permission or an address update is required, the agent can call request_delivery_permission so OnceAsk can route the recipient through address confirmation.
Not for the preferred fulfillment flow. OnceAsk can issue an opaque, short-lived delivery token for supported physical-delivery actions so the destination can move server-to-server without being returned as ordinary model output.
SOURCES
Build an address book that is still useful the next time you need it.
Create your OnceAsk