Claude MCP elicitation forms that ask for values are declined without a prompt #35996

What happened#

On a Claude thread, an MCP server sends elicitation/create (form mode) with a required value field, for example a confirmation code the user must type. T3 shows nothing and answers { action: "decline" } within 2–8 ms. The tool then reports that the user refused, although the user never saw a question. The same form on an ACP provider opens a question card.

Diagnosis#

ClaudeAdapterV2.onElicitationEffect only handles forms that claudeMcpElicitationAcceptance can answer with a plain approval (#21903). Any form whose required fields need a value makes it return undefined, so the adapter logs "Declined an MCP elicitation the approval card cannot answer." and declines. The ACP adapter maps the same schemas to the user_input question card through parseElicitationForm (packages/provider-acp/src/server/elicitationForm.ts); the Claude adapter never uses it.

Steps to reproduce#

1. Add a stdio MCP server to a project whose tool calls elicitInput({ mode: "form", message: "Confirm loading PROJ-123", requestedSchema: { type: "object", properties: { code: { type: "integer", description: "Type 713321 to confirm." } }, required: ["code"] } }).
2. In a Claude thread, ask the agent to call that tool.
3. No card appears. The server receives { action: "decline" }.

Version#

Desktop 0.1.9 (Linux). Also reproduced on main at 0a333a69 built from source.

Environment#

Linux, T3 Code desktop AppImage and a source build of apps/server; Claude Code 2.1.322 (client declares elicitation: { form: {}, url: {} }).

Evidence#

Results from a test MCP server with one tool per elicitation type (spec 2025-11-25), identical on 0.1.9 and main:

• required string / string formats / number / enum (plain, titled, legacy) / multi-select / combined form: decline in 2–9 ms, no card
• boolean, titled multi-select and empty schema without required fields: approval card, accept with content: {}
• URL mode: decline (covered by #33211)

Related issues#

#14878, #21903, #33575, #31315, #33211

Fix applied or workaround#

None in the product. A fix that routes these forms to the existing question card is ready as a PR.

Filed by#

Claude Opus 5.5 in Claude Code via T3 Code, on behalf of the user.