Sonntet 4.5 thinking boxes are not showing despite thinking boxes enabled.

Hey,

I have been using sonnet 4.5 through OpenRouter and it doesnt seem like the thinking boxes are working despite thinking being enabled.

Model options also have correctly configured thinking with thinking budget set to 32k.

This is opencode:

Same prompt with Crush without any provider options:

So the opencode results are way more detailed and its taking more time than Crush because of my thinking settings, so i am certain its thinking but its not showing inside the tui.

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

Thinking Function and Thinking Blocks Visibility Issues #2484: Reports thinking blocks not being visible for Claude and other models despite being configured correctly
Git Copilot claude 3.7 sonnet thinking is not working in the opencode CLI #2305: GitHub Copilot Claude Sonnet thinking not working in OpenCode CLI
[bug] v0.8.0 Introduced thinking block bug with Claude Sonnet 4: "AI_APICallError: messages.3.content.0.type: Expected thinking or redacted_thinking, but found text." #2599: v0.8.0 introduced thinking block bugs with Claude Sonnet 4, causing API errors with thinking blocks

Your issue with Sonnet 4.5 thinking boxes not displaying through OpenRouter appears very similar to these previous reports about thinking blocks visibility issues with Claude models.

Feel free to ignore if none of these address your specific case.

@XSIRIX

@XSIRIX can you show your opencode.json

@rekram1-node

@rekram1-node hey yea:

Hm I think when you are using openrouter the settings are different than they would be for an anthropic model ususally let me see

Im using all default still I dont see the thinking sections

@Amansaxena001

@Amansaxena001 that's because thinking isn't enabled by default, I know what the settings look like for most providers I haven't seeen what it is for openrouter tho it doesnt seem to work for them. SO I am guessing there is a setting naming difference that needs to be documented

@Amansaxena001 that's because thinking isn't enabled by default, I know what the settings look like for most providers I haven't seeen what it is for openrouter tho it doesnt seem to work for them. SO I am guessing there is a setting naming difference that needs to be documented

Ok i know the reason why, im blind.

Basically, i am switching between plan and build mode all the time, and for whatever reason the model keeps switching as well between official Claude Sonnet 4.5 model where extended thinking is disabled and my custom configured sonnet 4.5 model where thinking is working.

Here in build mode:

After switching to plan mode with tab model switches:

this looks like a bug to me

@XSIRIX

@XSIRIX when you switch models for a agent, we save the last used model, so when u are switching agents it also switches models to what u last used when uding that agent, unless ofc you hardcode the model in the agent definition

does this resolve issue? Or are you still having problems just wanna make sure I am following you correctly

I haven't been able to enable thinking when using Claude with OAuth

I tried the config here:

https://opencode.ai/docs/models/#configure-models

{
  "$schema": "https://opencode.ai/config.json",
  "provider": {
    "openai": {
      "models": {
        "gpt-5": {
          "options": {
            "reasoningEffort": "high",
            "textVerbosity": "low",
            "reasoningSummary": "auto",
            "include": ["reasoning.encrypted_content"],
          },
        },
      },
    },
    "anthropic": {
      "models": {
        "claude-sonnet-4-5-20250929": {
          "options": {
            "thinking": {
              "type": "enabled",
              "budgetTokens": 16000,
            },
          },
        },
      },
    },
  },
}

@numman-ali

@numman-ali oh did you try /thinking in the tui?

Yes, I'm pretty confident there's an issue with how options may be passed to opencode, and no thinking ever occurs on the Sonnet 4.5 model

I made the OpenAI OAuth Plugin https://github.com/numman-ali/opencode-openai-codex-auth so I'm pretty familiar with how opencode works

I don't have time to review atm, but confident it's how the AI SDK Provider for Anthropic is mapping the properties from OpenCode config, there's a missing piece

@numman-ali

@numman-ali if you are using anthropic then that config works:

Can you run opencode debug config and show me output? And you are using anthropic right not openrouter or any other provider

I copied your config verbatim and sent "hello" to claude sonnet 4.5, thinking shows as expected

It seems that it works if i use

                "claude-sonnet-4-5-20250929": {
                    "name": "Claude Sonnet 4.5 Thinking",
                    "options": {
                        "thinking": {
                            "type": "enabled",
                            "budgetTokens": 16000,
                        }
                    }
                },

but if i use it with custom id, it does not

                "claude-sonnet-4-5-thinking": {
                    "id": "claude-sonnet-4-5-20250929",
                    "name": "Claude Sonnet 4.5 Thinking SWAG",
                    "options": {
                        "thinking": {
                            "type": "enabled",
                            "budgetTokens": 16000,
                        }
                    }
                },

@rekram1-node

@rekram1-node can you check it please?

yes I will, I managed to replicate, I know issue

@rekram1-node

There is "alwaysThinkingEnabled": false in settings.json file which works @rekram1-node

this should be fixed

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Sonntet 4.5 thinking boxes are not showing despite thinking boxes enabled. #2919

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Sonntet 4.5 thinking boxes are not showing despite thinking boxes enabled. #2919

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github-actions commented on Oct 2, 2025

rekram1-node commented on Oct 2, 2025

XSIRIX commented on Oct 2, 2025

rekram1-node commented on Oct 2, 2025

Amansaxena001 commented on Oct 3, 2025

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