Anthropic provider: 400 on MCP tools with top-level oneOf/anyOf/allOf in input_schema (and [tools].disabled doesn't filter MCP tools from the wire)

Bug: MCP tool schemas with top-level oneOf/anyOf/allOf are rejected by the Anthropic API (400)

Summary

When using an anthropic-type provider (Claude models), any MCP server that exposes a tool whose inputSchema has a top-level oneOf/anyOf/allOf combinator makes every request fail with a 400 from the Anthropic API — even the first "hello" of a fresh session, because the full tool list is sent on every call. Kimi models tolerate these schemas; the Anthropic Messages API does not.

Error

provider.api_error: 400 {"type":"error","error":{"type":"invalid_request_error",
"message":"tools.92.custom.input_schema: input_schema does not support oneOf, allOf, or anyOf at the top level"},
"request_id":"req_011CdUrw2Nqi8JkRad2CvumV"}

Steps to reproduce

1. Configure an anthropic provider + model alias in config.toml (e.g. claude-sonnet-5).
2. Add an MCP server whose tools include a top-level combinator in inputSchema. In my case the Higgsfield MCP server (https://mcp.higgsfield.ai/mcp) — its video_analysis_create tool declares:

   { "oneOf": [
       { "required": ["video_input_id"] },
       { "required": ["youtube_url"] }
   ] }
   

   at the root of inputSchema (verified via raw JSON-RPC tools/list; it is the only one of the server's 86 tools with a root-level combinator).
3. Run kimi -m claude-sonnet-5 -p "coucou" → 400 on the very first request. The same session works fine with a Kimi model.

Expected

The CLI sanitizes/wraps tool schemas before sending them to the Anthropic API (e.g. hoisting a root-level oneOf into a plain object schema with optional properties, or dropping/replacing the offending tool with a warning), so one non-conforming MCP tool cannot brick the entire session.

Workarounds found

• disabledTools: ["video_analysis_create"] on the server entry in mcp.json → session works. ✅ (only fix that works)
• [tools].disabled = ["mcp__higgsfield__*"] in config.toml does not help: MCP tools are still sent on the wire despite the global tool switch. This looks like a second, related bug — the global [tools] filter does not apply to MCP tools (at least for request shaping).

Environment

• kimi-code 0.29.2
• Linux (WSL2, Ubuntu 24.04)
• Provider: anthropic (official API, model claude-sonnet-5)

Happy to email a debug ZIP (kimi export) or the raw tools/list dump if useful — not attaching here since they may contain session data.

Start by tracing the Anthropic provider's request shaping for MCP tool schemas, then inspect how the global [tools].disabled setting is applied compared with disabledTools in mcp.json. Reproduce with the Higgsfield tools/list schema and an Anthropic model; done means the request no longer fails on a top-level combinator and disabled MCP tools are absent from the wire.