---
title: "Can this agent reach this number over RCS?"
method: GET
path: "/v1/agents/{id}/reachability"
tags: ["Google & carriers"]
---

# Can this agent reach this number over RCS?

`GET /v1/agents/{id}/reachability`

## Request

- Base URL: `https://api.cadencercs.com`
- URL: `https://api.cadencercs.com/v1/agents/{id}/reachability`
- Auth: HTTP bearer

Folds in every reason a send might not land: the device has no RCS, the agent isn't launched on that carrier, or the number simply hasn't used RCS lately. **Point-in-time** — Google only answers for numbers seen on RCS in roughly the last 31 days, so never cache it as a permanent fact.

`false` is not a dead end: the send falls back to SMS. The value is knowing before you send.

**Not available on a sandbox key.** It asks Google about a real agent, and a sandbox account has none — it answers `409 AGENT_NOT_MAPPED` until `sync-google` has run, which is irreversible. Sending needs none of this: `POST /v1/conversations` resolves a channel and simulates delivery in sandbox, so treat this as a go-live check rather than a build-time one.

## Path parameters

- `id` string, required

## Query parameters

- `to` string, required

## Response `200`

Point-in-time answer.

- object
  - `to` string, required
  - `reachable` boolean, required
  - `channel` 'rcs' | 'sms', required: What a send right now would use.
  - `launchedCarriers` string[]
  - `note` string
  - `remediation` string

## Other responses

- `400`: `to` must be E.164.
- `401`: Not signed in, and no account-linked API key was sent.
- `404`: No such agent on this account.
- `409`: This agent doesn't exist at Google yet.
- `500`: Unexpected server error. The body is always JSON.
- `502`: Google rejected the request.
- `503`: This deployment's backend can't check reachability.

---

[API](https://skmtc.dev/cadencercs/apis/cadence-api.md) · [All operations](https://skmtc.dev/cadencercs/apis/cadence-api/llms.txt) · [OpenAPI document](https://skmtc.dev/cadencercs/apis/cadence-api/revisions/9438443c2081?raw)