[Bug] OpenCode Go: kimi-k2.6 fails with HTTP 400 'cannot specify both thinking and reasoning_effort' — works via plain client #38329

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1. github-actions commented on Jul 22, 2026

   

   github-actionsBot

   on Jul 22, 2026 – with GitHub Actions

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   This issue doesn't fully meet our contributing guidelines.

   What needs to be fixed:

   • The issue does not use one of the three required templates (Bug Report, Feature Request, or Question). Please resubmit using the appropriate template.
   • The description appears to be AI-generated. We do not accept AI-generated walls of text — please describe the problem in your own words with the essential details only.

   Please edit this issue to address the above within 2 hours, or it will be automatically closed.

   ---

   This issue might be a duplicate of existing issues. Please check:

   • Cannot use Kimi or Qwen models in Opencode Go plan #38219: Kimi and Qwen models unusable on OpenCode Go plan (same symptoms)
   • OpenCode Go: kimi-k3, kimi-k2.6, kimi-k2.7-code, glm-5.2, grok-4.5, qwen3.7-max, hy3-preview all fail with 'Upstream request failed' — non-standard 'mcp'/'system' fields rejected by strict provider validators #37771: kimi-k2.6 and other models failing with upstream request errors due to non-standard fields (directly overlaps with the mcp/system field rejection described here)

   If you believe this was flagged incorrectly, please let a maintainer know.
2. github-actions

   added

   needs:complianceThis means the issue will auto-close after 2 hours.This means the issue will auto-close after 2 hours.

   on Jul 22, 2026
3. github-actions

   assigned

   MrMushrooooom

   on Jul 22, 2026
4. AlfieChang

   changed the title [-]OpenCode Go: kimi-k2.6 returns HTTP 400 (thinking/reasoning_effort conflict) while kimi-k3 works — K3 fixes never ported to K2.6[/-] [+][Bug] OpenCode Go: kimi-k2.6 fails with HTTP 400 'cannot specify both thinking and reasoning_effort' — works via plain client[/+] on Jul 22, 2026
5. github-actions

   removed

   needs:complianceThis means the issue will auto-close after 2 hours.This means the issue will auto-close after 2 hours.

   on Jul 22, 2026
6. github-actions commented on Jul 22, 2026

   

   github-actionsBot

   on Jul 22, 2026 – with GitHub Actions

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   Thanks for updating the issue! It now looks good — the description is clear and specific, steps to reproduce are provided, and the required fields are filled in. We'll take a look.
7. opencode-agent commented on Jul 23, 2026

   

   opencode-agentBot

   on Jul 23, 2026 – with OpenCode Agent

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   Closing as unable to reproduce on current dev (743f6410f2e5002723fc5e893039ac49fbfe0de8).

   This cannot happen out of the box with the current model definition and request transforms:

   • OpenCode Go uses the OpenAI-compatible transport: https://github.com/anomalyco/opencode/blob/743f6410f2e5002723fc5e893039ac49fbfe0de8/packages/opencode/test/tool/fixtures/models-api.json#L33606-L33610
   • kimi-k2.6 has no configured reasoning options, so it does not generate a reasoningEffort variant: https://github.com/anomalyco/opencode/blob/743f6410f2e5002723fc5e893039ac49fbfe0de8/packages/opencode/test/tool/fixtures/models-api.json#L34133-L34141
   • Reasoning-effort variants are only generated when the model advertises an effort option:

     opencode/packages/opencode/src/provider/transform.ts

     Lines 1635 to 1640 in 743f641

     	const effort = options.find((option) => option.type === "effort")
     	if (effort) return effortVariants(target, effort.values)
     	const toggle = options.some((option) => option.type === "toggle")
     	const budget = options.find((option) => option.type === "budget_tokens")
     	if (!budget) return toggle ? nonEmptyVariants(reasoningToggle(target)) : undefined

   • Kimi thinking injection is guarded to Anthropic-compatible transports, which this model is not using:

     opencode/packages/opencode/src/provider/transform.ts

     Lines 1217 to 1226 in 743f641

     	// Moonshot's Anthropic-compatible API uses adaptive effort rather than token budgets.
     	// Request summaries so thinking content survives replay on subsequent turns.
     	if (
     	["@ai-sdk/anthropic", "@ai-sdk/google-vertex/anthropic"].includes(input.model.api.npm) &&
     	isKimiFamily(input.model) &&
     	input.model.capabilities.reasoning
     	) {
     	result["thinking"] = { type: "adaptive", display: "summarized" }
     	result["effort"] = "high"
     	}

   The successful minimal direct API request only establishes that the endpoint accepts a minimal payload; it does not reproduce the alleged OpenCode request envelope. The report also omits the OpenCode version and the actual failing outbound JSON.

   If this still occurs, please provide the exact OpenCode version or commit, complete command, selected variant, relevant model/provider configuration or overrides, and the sanitized exact outbound JSON body (with credentials and private content removed). We can reopen once there is an exact reproduction.
8. opencode-agent

   closed this as not plannedon Jul 23, 2026