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Grok can add a custom MCP server by URL. Point it at Sempera and it can ask to make calls and send texts, each of which you approve. Status: Unverified. The server side is built and tested against the published standards, but no real Grok account has completed the connection yet (Supported clients). If a screen differs from these steps, tell hello@sempera.org and this page will be corrected.

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Add Sempera by URL

Add a custom MCP server in Grok and enter:
Grok’s documentation does not say how a custom server signs in, so the first real connection decides which of these applies:
  • If Grok offers OAuth, it follows the same steps as ChatGPT and Claude, and appears on Sempera’s consent page as an unverified app with its real redirect host. Check the name and host before you approve.
  • If Grok only accepts a header, create a REST credential with only the phone permissions you want under Settings, Connected clients, and give Grok the header below.
Keep the credential out of the chat itself. Enter it only where Grok stores connector secrets.

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Check the connection

Ask the assistant for your Sempera Phone number and what is left this period. That is a read: it places nothing and needs only phone:read. The same read over plain HTTP, with a phone credential from Settings, Connected clients:
An ordinary workspace API key is refused on the phone routes: every phone credential is a connected client (an OAuth grant, an MCP connection or a REST credential), so it can be revoked on its own.

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What happens on a call

  1. The assistant calls phone_preview_call (or POST /v1/phone-tasks/preview) with the number, the task, the permitted_actions and an optional max_minutes. Nothing is dialled or reserved. The answer carries an approval link, or standing: true if a standing approval covers that number.
  2. You open the link signed in to Sempera, read the exact request and approve or decline. The approval is good for five minutes.
  3. The assistant calls phone_start_call with the same values. Any change is refused. The task moves to reserved, which means queued, not dialling.
  4. The assistant follows the task with phone_get_task until completed, failed or cancelled. The result is marked untrusted: it was written from what someone else said.
Texts work the same way with phone_preview_text and phone_send_text. The full rules, limits and refusal codes are in Personal phone plan.

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Before the first call

The plan is not open for purchase yet. When it opens, a first call also needs a number on the account and a published Sempera agent pinned to the plan; until then a start is refused with PHONE_PLAN_INACTIVE, PHONE_NUMBER_MISSING or PHONE_AGENT_UNPINNED. Calls and texts go out only while it is between 9 a.m. and 9 p.m. in both Toronto and Vancouver (noon to 9 p.m. Eastern); outside that window they are refused with PHONE_OUTSIDE_HOURS.

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Disconnect

Open Settings, Connected clients in the Sempera App and revoke the client. That ends its credential at once and leaves every other assistant working. Grok is a trademark of its owner, used here only to say which assistant connects. Sempera is not affiliated with, sponsored by or endorsed by the maker of Grok.