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Apostra’s V3 MCP (Model Context Protocol) server at https://api.apostra.com/mcp/v3 connects to a coding agent such as Claude Code or Codex with browser OAuth. After sign-in, get_status proves account access and writes nothing. A search with {"kind":"seller","limit":10} then lists sellers for a discovery prototype, still without contacting any seller or spending money.

Your options

The last three rows describe each vendor’s own documentation as of 13 November 2026, linked under Sources. Check them again before you rely on them. Each of those three servers works inside its own platform’s account. For a seller-discovery prototype that lists sellers to choose from, use the Apostra connection: search with {"kind":"seller"} lists the sellers connected through Apostra. A seller here is an advertising seller, such as a publisher, a sales house or an ad platform, not a seller on an e-commerce marketplace.

Connect and verify

  1. Install the plugin, or add the server directly.
    For Codex, run codex plugin marketplace add https://github.com/apostra-public/apostra.git and codex plugin add apostra-developer@apostra. To work in your account without a plugin, run claude mcp add --transport http apostra https://api.apostra.com/mcp/v3 and claude mcp login apostra, or the Codex equivalent codex mcp add apostra --url https://api.apostra.com/mcp/v3 and codex mcp login apostra.
  2. Complete OAuth in the browser. Adding a server is not proof that sign-in has finished.
  3. Ask the agent for a read-only check:
  4. Make the first discovery read. For a Buyer Account, call search with {"kind":"seller","limit":10}. An empty list is a valid result, not a failed connection.

What this proves, and what it does not

get_status proves the connection can reach the account. It does not prove that every advertiser, seller or write operation is authorized. The seller list shows each seller’s connection and readiness for this buyer. It does not send a brief. request_proposals is the later step that does, so run it only when the user has asked your application to start that workflow. Every call after the first names its account with the accountId that get_status returned. Your OAuth identity never grants access you do not already have.

When not to use this connection

  • Your software runs unattended. Interactive OAuth represents you in the coding session. Deployed software needs its own credential: an API key or an M2M application on the HTTP API, or an agent registered in an Agents account. See Authentication.
  • Your client cannot connect to a remote Streamable HTTP MCP server. Use the V3 HTTP API or an SDK instead.
  • You work on one platform only. That platform’s own MCP may expose features Apostra’s connection does not.
  • You use regular Claude or Cowork rather than Claude Code or Codex. They do not use the developer plugin. Follow the hosted connector setup.

Next step

Run the install commands above, then ask your agent to call get_status. For a fuller prototype prompt and the failure table, read Connect in five minutes. To add buying steps with approval, read Build an agent.

Sources