MCP elicitation over remote streamable HTTP: dialog renders, user's Accept never reaches the server (works over stdio)

[awhitford]

Environment

• ChatGPT Desktop (Mac) 26.810.50856 (released 2026-08-14)
• Embedded MCP client: codex-mcp-client 0.148.0-alpha.9
• Remote MCP server over streamable HTTP (TypeScript SDK 1.x), OAuth-authenticated
• Client capabilities advertised: elicitation: { form: {}, url: {} }

Behavior

The server issues elicitation/create (form mode, a simple single-select enum schema). The dialog renders correctly in ChatGPT Desktop and the user clicks Accept/OK — but the response never reaches the server: the server-side elicitation/create request fails with an error ~6 seconds later.

Observed identically for two different requests in the same session:

• a diagnostic probe elicitation: server-side error after 6104 ms
• a confirm dialog ("Need help?" with OK/Cancel options): user clicked OK; the server received an error instead of the accept

Works over stdio

The same host (ChatGPT Desktop 26.810.41047, same codex-mcp-client 0.148.0-alpha.9) against a local stdio MCP server completes the identical elicitation end-to-end: dialog renders, user accepts, { action: "accept", content: { value: "ok" } } arrives at the server (~10 s human latency, negotiated protocol 2025-06-18).

Expected

The user's Accept (with content) is delivered to the server as the elicitation/create response, exactly as it is over stdio.

Possibly related

• rmcp_client: Add MCP elicitation support #6992 (rmcp_client elicitation support — closed; this bug appears to be in the response-delivery path added after that)
• Elicitation fails with NoContent error when client sends empty content on Accept #9053 (Accept arrived with content: None — closed; here the Accept doesn't arrive at all)
• Elicitation support #13405 (umbrella elicitation compliance)

[SankeerthNara]

Could you assign this to me