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Console Go: Anthropic-route tool calls fail with 400 'function name is invalid' for Kimi models (kimi-k3, kimi-k2.7-code) #41120
Description
Summary
Requests to https://opencode.ai/zen/go/v1/messages (Anthropic route) with any tool that carries an input_schema fail with HTTP 400 for the Kimi models (kimi-k3, kimi-k2.7-code). Other models on the same route accept the identical request.
Error
400 invalid_request_error
"Error from provider (Console Go): Upstream request failed: [invalid_request_error] Invalid request: function name is invalid, must start with a letter and can contain letters, numbers, underscores, and dashes"
The error is misleading: the tool names are all valid (Bash, Edit, mcp__codegraph__codegraph_explore, ...). Bisection shows the trigger is the presence of the input_schema key, not its content and not the name.
Reproduction
- Build an Anthropic
/v1/messagesrequest withmodel: "kimi-k3"and any single tool, e.g.:{"name": "Bash", "description": "run", "input_schema": {"type": "object", "properties": {"command": {"type": "string"}}}} - POST to
https://opencode.ai/zen/go/v1/messageswith anopencode-gokey. - Result: 400 with the error above.
Bisection results (same body, only the tool definition varied, model kimi-k3):
| tool definition | result |
|---|---|
name only |
OK |
name + description |
OK |
name + description + input_schema (any content, even {}) |
400 |
same with deepseek-v4-flash / qwen3.8-max / minimax-m3 / gpt-5.6-luna |
OK |
same with kimi-k2.7-code |
400 |
same with glm-5.2 |
422 |
grok-4.5 |
401 "Model grok-4.5 is not supported for format anthropic" |
Additional data
- The OpenAI route works for the same models:
POST /v1/chat/completionswithtools: [{type: "function", ...}]onkimi-k3succeeds. So this is specific to the Anthropic-route tool-schema conversion for the Kimi upstream. - Affects every Claude Code session pointed at
ANTHROPIC_BASE_URL=https://opencode.ai/zen/gowith a Kimi model — the very first request fails because Claude Code always sends tool schemas. - Workaround today: use a non-Kimi model (
qwen3.8-max,minimax-m3,deepseek-v4-flash,gpt-5.6-luna) on the Anthropic route. Claude Code's native OpenAI env route is not an alternative in v2.1.220 (it rejects models not in its own list).
Environment
- Gateway:
opencode.ai/zen/go("Console Go" provider) - Client: Claude Code 2.1.220, also plain HTTP replay against the gateway (no client involved)
- Date: 2026-08-07
Activity
github-actions commentedon Aug 7, 2026
This issue might be a duplicate of existing issues. Please check:
kimi-k2.7-code+ Anthropic/v1/messages+ tools → 400 "function name is invalid" symptom on the zen/go gatewaygoldyard2022 commentedon Aug 14, 2026
Update as of 2026-08-15 (from #42616, closing as dup):
Kimi appears to be fixed on this route.
kimi-k3with a tool carryinginput_schema(the exact repro shape above) now returns 200 with a cleantool_useblock:{"type":"tool_use","id":"get_weather_0","name":"get_weather","input":{"city":"北京"}}The GLM branch is still broken, and the failure now spans the whole GLM family. Same request, same key, same endpoint:
glm-5.3(newly listed ~08-14)[1210] Invalid API parameterglm-5.2tools.0.function-after[_domain_filters(), WebSearchTool].type—Input should be 'web_search'glm-5.1kimi-k3qwen3.7-plusglm-5.3via OpenAI route/v1/chat/completionstool_callsglm-5.2via Zhipu nativeopen.bigmodel.cn/api/anthropictool_useThe glm-5.2/5.1 422 param path is the most interesting clue — it looks like the Anthropic→GLM translation emits something in Zhipu's web_search tool format (
WebSearchTool,_domain_filters()) instead of a plain function tool. glm-5.3 is presumably routed to a different upstream (it fails with[1210]instead), but the trigger is the same: any non-emptytoolson the Anthropic route, regardless of tool shape.Also reproduced across 3 independent Go-plan keys, so it's not account-specific.
Side note: Zhipu's native Anthropic endpoint now returns
"model": "glm-5.3"when you requestglm-5.2— the alias seems repointed upstream, in case that matters for how the gateway routes GLM traffic.github-actions commentedon Oct 15, 2026
To stay organized issues are automatically closed after 60 days of no activity. If the issue is still relevant please open a new one.