Support adaptive thinking for Claude Opus 4.6 #12485

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1. github-actions

   assigned

   thdxr

   on Feb 6, 2026
2. BouquetAntoine commented on Feb 6, 2026

   

   BouquetAntoine

   on Feb 6, 2026

   Last edited by BouquetAntoine

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   OpenCode currently depends on @ai-sdk/anthropic v2.x. Simply bumping the dependency to v3.x and rebuilding isn't enough — there are several breaking changes in the SDK that need to be addressed in the codebase.

   Below is a summary of every breaking change identified so far, tried different fixes in my codebase but that's a lot of work.

   ---

   1. finishReason format change

   v2.x returns a plain string:

   finishReason: "end_turn" | "tool_use" | "stop_sequence" | ...

   v3.x returns an object with unified and raw properties:

   finishReason: {
     unified: "stop" | "tool-calls" | "error" | "other" | ...
     raw: string | undefined
   }

   ---

   2. usage token counts format change

   v2.x returns flat numbers:

   usage: {
     inputTokens: 1234,
     outputTokens: 567,
     cachedInputTokens: 100,
     reasoningTokens: 200,
   }

   v3.x returns nested objects:

   usage: {
     inputTokens:    { total: 1234, noCache: 1034, cacheRead: 200 },
     outputTokens:   { total: 567, text: undefined },
     reasoningTokens: 200, // may also be an object
   }

   ---

   3. New providerOptions schema (thinking / effort)

   v2.x supports a limited thinking config:

   thinking: {
     type: "enabled" | "disabled",
     budgetTokens?: number,
   }
   // No "effort" field

   v3.x adds an adaptive mode and a new top-level effort field:

   thinking: {
     type: "adaptive" | "enabled" | "disabled",
     budgetTokens?: number, // only required when type is "enabled"
   }
   effort: "low" | "medium" | "high" | "max" // NEW

   Fix

   Update config schema validation (e.g. Zod schemas or type definitions) to accept the new "adaptive" type and the effort field.

   ---

   Problem is that we probably need to update all ai-sdk to last version for compatibility across models
3. avarayr commented on Feb 6, 2026

   

   avarayr

   on Feb 6, 2026

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   I was able to temporarily hack this to work until fix is in place.

   Note: this is not a long term solution, just an unblocker until this issue is fixed.

   // File: ~/.opencode/plugins/adaptiveThinking.ts
   export const adaptiveThinking: import("@opencode-ai/plugin").Plugin =
     async () => ({
         loader: async () => {
           return {
             fetch: async (url: RequestInfo | URL, init?: RequestInit) => {
               const body = init?.body
                 ? JSON.parse(init.body as string)
                 : undefined;
                 
               if (body?.thinking?.budget_tokens === -1) {
                 body.thinking = { type: "adaptive" };
                 return fetch(url, { ...init, body: JSON.stringify(body) });
               }
               return fetch(url, init);
             },
           };
         },
       },
   
       // Shim: rewrite adaptive -> enabled with sentinel budget so SDK Zod passes,
       // then the custom fetch above detects budget_tokens:-1 and patches to adaptive.
       "chat.params": async (_input, output) => {
         if (output.options?.thinking?.type === "adaptive") {
           output.options.thinking = { type: "enabled", budgetTokens: -1 };
         }
       },
     });

   // File: ~/.config/opencode/opencode.jsonc
   {
      "plugin": [
           "file:///Users/<USERNAME>/.opencode/plugin/adaptiveThinking.ts",
       ],
   	"provider": {
   	        "anthropic": { // <-- replace with your provider of choice
   	            "models": {
   	                "claude-opus-4-6@20260205": { // might need replacement based on provider
   	                    "id": "claude-opus-4-6",
   	                    "name": "Claude Opus 4.6",
   	                    "family": "claude-opus",
   	                    "attachment": true,
   	                    "reasoning": true,
   	                    "tool_call": true,
   	                    "temperature": true,
   	                    "knowledge": "2025-05",
   	                    "release_date": "2026-02-05",
   	                    "last_updated": "2026-02-05",
   	                    "modalities": {
   	                        "input": [
   	                            "text",
   	                            "image",
   	                            "pdf"
   	                        ],
   	                        "output": [
   	                            "text"
   	                        ]
   	                    },
   	                    "open_weights": false,
   	                    "cost": {
   	                        "input": 5,
   	                        "output": 25,
   	                        "cache_read": 0.5,
   	                        "cache_write": 6.25,
   	                        "context_over_200k": {
   	                            "input": 10,
   	                            "output": 37.5,
   	                            "cache_read": 1,
   	                            "cache_write": 12.5
   	                        }
   	                    },
   	                    "limit": {
   	                        "context": 200000,
   	                        "output": 128000
   	                    },
   	                    "variants": {
   	                        "adaptive": {
   	                            "thinking": {
   	                                "type": "adaptive" // special case handled by plugin
   	                            }
   	                        },
   	                        "high": {
   	                            "thinking": {
   	                                "type": "enabled",
   	                                "budgetTokens": 16000
   	                            }
   	                        },
   	                        "max": {
   	                            "thinking": {
   	                                "type": "enabled",
   	                                "budgetTokens": 128000
   	                            }
   	                        }
   	                    }
   	                }
   	            }
   	        }
   	    },
   }
4. BouquetAntoine commented on Feb 6, 2026

   

   BouquetAntoine

   on Feb 6, 2026

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   #12342 will fix this soon

   🚀React with 🚀1Reacted by Oscar Serna
5. github-actions commented on Apr 8, 2026

   

   github-actionsBot

   on Apr 8, 2026 – with GitHub Actions

   Contributor

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   To stay organized issues are automatically closed after 90 days of no activity. If the issue is still relevant please open a new one.
6. github-actions

   closed this as completedon Apr 8, 2026