Codex custom Responses provider: can it point at Sume?

Codex CLI 0.162.0 adds custom Responses-compatible provider config. Sume's Agent Completions is not a model endpoint; use Sume's hosted MCP from Codex instead.

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No. Codex CLI 0.162.0 (Oct 8) adds configuration for a custom Responses-compatible model provider, but Sume does not document a Responses-compatible endpoint. Agent Completions at POST /v1/agent/completions returns a 202 receipt for a run, with model fixed to sume-agent. To use Sume from Codex, add the hosted MCP server.

What did Codex add?

The Codex changelog lists 0.162.0 with managed Git worktree tools, task pinning and custom Responses-compatible provider configuration. 0.161.0 (Oct 7) added a /mcp login <name> terminal command and enterprise MCP sign-in.

Codex changelog (read 2026-10-09)
VersionDateRelevant items
0.162.0Oct 8 2026Custom Responses-compatible provider config; managed worktree tools; task pinning
0.161.0Oct 7 2026/mcp login <name>; enterprise MCP sign-in

Why is Agent Completions not a provider?

A model provider answers a prompt with tokens. Agent Completions starts a Sume agent run:

  • It returns 202 with an agent.run receipt and a status_url to poll.
  • model accepts only sume-agent.
  • It takes exactly one of instruction or messages[], and rejects assistant turns.
  • generation_spend_cap_usd is required.
  • Service-account keys are refused.

What should Codex use?

Codex as the agent, Sume as the tools. Add https://mcp.sume.com/mcp as a remote server, sign in with /mcp login or use a key, and let Codex call generate_video, jobs_wait and the rest. Choose Agent Completions when you want Sume to host the run and call you back with a signed agent.run.terminal event. Details are in Agent Completions.

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