# Custom MCP server in Codex Web

**URL:** <https://community.openai.com/t/custom-mcp-server-in-codex-web/1378356>\
**Category:** Codex\
**Tags:** codex, support, mcp, codex-cloud\
**Created:** [April 2, 2026, 7:44am UTC](https://community.openai.com/t/custom-mcp-server-in-codex-web/1378356 "2026-04-02T07:44:29Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Maksym\_Dakal](https://avatars.discourse-cdn.com/v4/letter/m/e95f7d/32.png) [@Maksym\_Dakal](https://community.openai.com/u/Maksym_Dakal)\
**Post date:** [April 2, 2026, 7:44am UTC](https://community.openai.com/t/custom-mcp-server-in-codex-web/1378356/1 "2026-04-02T07:44:29Z")

</div>

#support #codex #codex-web #codex-cloud #mcp

We tested custom MCP registration in Codex Web by appending a Datadog MCP server to `/opt/codex/config.toml` during setup.

What we verified:

- the MCP config is present on disk after setup;
- required environment variables are present;
- the Datadog MCP endpoint is reachable from the runtime;
- however, no Datadog MCP tools are exposed in the active Codex Web session.

This suggests that modifying `/opt/codex/config.toml` during setup is not sufficient to register custom MCP servers in Codex Web, and that MCP tool availability is controlled by platform/session bootstrap rather than runtime config changes.

Can you confirm:

- whether custom MCP servers are officially supported in Codex Web / Codex Cloud;
- if supported, what the correct setup path is;
- if not supported, whether this is a planned capability?