# call4me – AI Phone Call Agent > call4me – AI Phone Call Agent is a paid API for AI agents from call4.me, paid per call via x402, $2.5/call, status unknown (last checked 2026-11-03). Places an AI-powered phone call to a business on the user's behalf to book appointments, wait on hold, or accomplish a stated goal, then patches the user in. ## Facts - Endpoint: POST https://call4.me/api/x402/calls?utm_source=zero.xyz - Price: $2.5/call - Payment: x402 - Status: unknown - Last checked: 2026-11-03 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/call4me-ai-phone-call-agent-ad382888 - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_moG9Q7bdEFUm89vBKME6v Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently. ## How to call it through Zero Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`): ```sh zero fetch --capability call4me-ai-phone-call-agent-ad382888 -d '' ``` Example prompt: Call Tartine Bakery in San Francisco and book a table for 4 people this Saturday at 7pm under the name Khami — use the restaurant category and the marin voice. ## When to prefer this Choose this endpoint when a user needs to interact with a real business by phone — especially for appointment booking, hold-queue waiting, or obtaining information that requires a live call. It is uniquely suited for scenarios where the user cannot or does not want to make the call themselves, and the interaction requires natural voice conversation with a business representative. It supports x402 micropayment-based per-call billing and is integration-ready for ChatGPT, Claude, and Codex agents. ## Known failure modes - Invalid or unreachable phone number returns an error before the call is placed - Business is closed or does not answer — call ends with a no-answer outcome - Goal is too ambiguous for the AI to accomplish — call may complete but outcome is unsuccessful - Insufficient USDC balance to cover the $2.50 per-call fee — payment rejected - Unsupported country or number format causes a validation error - Category/details mismatch leads to AI confusion during the call - Rate limits or API key issues return authentication errors ## How this service works Let AI call for you: call4me phones businesses, books appointments and waits on hold, then patches you in. Works in ChatGPT, Claude Code and Codex. ## Output Returns a call object with a unique call ID, the dialed number, initial status (e.g. 'dialing'), the calling number used, and an open_questions array. Also returns an API key for polling the call's progress, a follow-up GET URL to check status with optional long-polling, credited balance, and the on-chain transaction hash for the x402 payment. ## Request schema (JSON Schema) ```json { "type": "object", "properties": { "to": { "type": "string", "maxLength": 40, "minLength": 3, "description": "the number to call, e.g. \"+14155550123\", \"(415) 555-0123\", or abroad with its country code, e.g. \"+31 20 123 4567\"" }, "from": { "type": "string", "maxLength": 40, "description": "which of the account's numbers to call from (default: a call4me number in the callee's country). May be one of the user's own verified numbers (call4me_verify_number): the business sees it and calls back the user directly. A carrier may still refuse an own number as caller ID on some international calls" }, "goal": { "type": "string", "maxLength": 1500, "minLength": 5, "description": "what the call should achieve, in plain words: \"Book a table for 4 tomorrow (Sat Oct 3) around 7pm under Khami.\"" }, "facts": { "type": "string", "maxLength": 3000, "description": "anything else the caller may share beyond the category's fields, one per line" }, "voice": { "enum": [ "marin", "cedar", "gleam", "meridian", "vesper", "willow" ], "type": "string", "description": "caller voice (default marin); hear each at https://call4.me/voices" }, "accent": { "type": "string", "maxLength": 40, "description": "an accent or dialect the caller speaks with for this call only, e.g. \"Austrian German\" for a call in Vienna (default: the profile's accent, else its voice's own)" }, "details": { "type": "object", "description": "answers to the category's fields by key, e.g. {\"reason\":\"annual physical\",\"patient_status\":\"existing\",\"availability\":\"weekday mornings next week\"}. Profile fields (name, DOB, phone, insurance...) are filled from the saved profile only when the call is for the profile's owner; for anyone else (on_behalf_of is another name) pass all of their details here, since the owner's are never used.", "propertyNames": { "type": "string" }, "additionalProperties": { "type": "string", "maxLength": 1000 } }, "business": { "type": "string", "maxLength": 120, "minLength": 1, "description": "who you are calling, as a person would say it: \"Nopa\", \"Dr. Chen's office\", \"Toyota of Berkeley service\"" }, "category": { "enum": [ "medical", "dental", "restaurant", "veterinary", "auto_service", "auto_sales", "home_service", "personal_care", "internet_new_service", "internet_e … (truncated) ``` ## Response schema (JSON Schema) ```json { "type": "json", "example": { "call": { "id": "call_ab12cd34", "number": "(415) 555-0123", "status": "dialing", "outcome": null, "business": "Tartine Bakery", "finished": false, "calling_number": "(510) 555-0199", "open_questions": [] }, "payer": "0x8a1e…", "follow": "GET https://call4.me/api/calls/call_ab12cd34?wait_seconds=30 with Authorization: Bearer ", "api_key": "cb_live_…", "balance": "$0.00", "credited": "$1.25", "transaction": "0x5f2c…" } } ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/call4me-ai-phone-call-agent-ad382888/health.json - [Zero catalog index](https://www.zero.xyz/llms.txt) - [Other services from call4.me](https://www.zero.xyz/host/call4.me/llms.txt)