feat: reasoning_details (#69)

Author: louisgv

README.md

@@ -37,8 +37,7 @@ const { text } = await generateText({
 
 ## Supported models
 
-This list is not a definitive list of models supported by OpenRouter, as it constantly changes as we add new models (and deprecate old ones) to our system.
-You can find the latest list of models supported by OpenRouter [here](https://openrouter.ai/models).
+This list is not a definitive list of models supported by OpenRouter, as it constantly changes as we add new models (and deprecate old ones) to our system. You can find the latest list of models supported by OpenRouter [here](https://openrouter.ai/models).
 
 You can find the latest list of tool-supported models supported by OpenRouter [here](https://openrouter.ai/models?order=newest&supported_parameters=tools). (Note: This list may contain models that are not compatible with the AI SDK.)
 
@@ -166,7 +165,7 @@ The provider supports [OpenRouter usage accounting](https://openrouter.ai/docs/u
 const model = openrouter('openai/gpt-3.5-turbo', {
   usage: {
     include: true,
-  }
+  },
 });
 
 // Access usage accounting data
@@ -178,6 +177,9 @@ const result = await generateText({
 // Provider-specific usage details (available in providerMetadata)
 if (result.providerMetadata?.openrouter?.usage) {
   console.log('Cost:', result.providerMetadata.openrouter.usage.cost);
-  console.log('Total Tokens:', result.providerMetadata.openrouter.usage.totalTokens);
+  console.log(
+    'Total Tokens:',
+    result.providerMetadata.openrouter.usage.totalTokens,
+  );
 }
 ```

biome.json

@@ -0,0 +1,83 @@
+{
+  "$schema": "https://biomejs.dev/schemas/1.9.4/schema.json",
+  "vcs": {
+    "enabled": true,
+    "clientKind": "git",
+    "useIgnoreFile": true
+  },
+  "formatter": {
+    "enabled": true,
+    "indentStyle": "space",
+    "indentWidth": 2,
+    "lineWidth": 80
+  },
+  "organizeImports": {
+    "enabled": true
+  },
+  "linter": {
+    "enabled": true,
+    "rules": {
+      "recommended": true,
+      "a11y": {
+        "useSemanticElements": "off"
+      },
+      "complexity": {
+        "useLiteralKeys": "off",
+        "noExtraBooleanCast": "off",
+        "noForEach": "off",
+        "noBannedTypes": "error",
+        "noUselessSwitchCase": "off"
+      },
+      "style": {
+        "noNonNullAssertion": "off",
+        "useNodejsImportProtocol": "off",
+        "useTemplate": "off",
+        "useBlockStatements": "error",
+        "noParameterAssign": "error",
+        "useConst": "error"
+      },
+      "correctness": {
+        "noUnusedImports": "error",
+        "useExhaustiveDependencies": "off",
+        "noUnknownFunction": "off",
+        "noChildrenProp": "off",
+        "noInnerDeclarations": "error"
+      },
+      "suspicious": {
+        "noExplicitAny": "off",
+        "noArrayIndexKey": "off",
+        "noAssignInExpressions": "error",
+        "noAsyncPromiseExecutor": "off",
+        "noFallthroughSwitchClause": "off",
+        "noConsole": "error",
+        "noDoubleEquals": {
+          "level": "error",
+          "options": {
+            "ignoreNull": true
+          }
+        },
+        "noExtraNonNullAssertion": "error"
+      },
+      "performance": {
+        "recommended": true,
+        "noAccumulatingSpread": "error"
+      },
+      "security": {
+        "recommended": true
+      }
+    }
+  },
+  "javascript": {
+    "formatter": {
+      "arrowParentheses": "always",
+      "jsxQuoteStyle": "single",
+      "attributePosition": "multiline",
+      "quoteProperties": "asNeeded",
+      "trailingCommas": "all",
+      "semicolons": "always",
+      "bracketSpacing": true,
+      "bracketSameLine": false,
+      "quoteStyle": "single"
+    }
+  }
+}

e2e/tools-with-reasoning.test.ts

@@ -0,0 +1,83 @@
+import type { UIMessage } from 'ai';
+
+import {
+  executeCommandInTerminalTool,
+  readSMSTool,
+  sendSMSTool,
+} from '@/e2e/tools';
+import { createOpenRouter } from '@/src';
+import { generateText } from 'ai';
+import { it, vi } from 'vitest';
+
+vi.setConfig({
+  testTimeout: 42_000,
+});
+
+const prompts = [
+  'The flight to San Francisco is delayed by 2 hours. Send an SMS to 808-999-2345 with the flight delay information.',
+  'Find out if the SMS was delivered properly.',
+];
+
+describe('Vercel AI SDK tools call with reasoning', () => {
+  it('should work with reasoning content', async () => {
+    const openrouter = createOpenRouter({
+      apiKey: process.env.OPENROUTER_API_KEY,
+      baseUrl: `${process.env.OPENROUTER_API_BASE}/api/v1`,
+    });
+
+    const model = openrouter('anthropic/claude-sonnet-4', {
+      usage: {
+        include: true,
+      },
+    });
+    const messageHistory: UIMessage[] = [];
+    for (const prompt of prompts) {
+      messageHistory.push({
+        id: crypto.randomUUID(),
+        role: 'user',
+        content: prompt,
+        parts: [
+          {
+            type: 'text',
+            text: prompt,
+          },
+        ],
+      });
+
+      const response = await generateText({
+        model,
+        system:
+          'You are an airline assistant. You can send and read SMS messages, and execute commands in the terminal.',
+        messages: messageHistory,
+        tools: {
+          readSMS: readSMSTool,
+          sendSMS: sendSMSTool,
+          executeCommand: executeCommandInTerminalTool,
+        },
+        maxSteps: 10,
+        providerOptions: {
+          openrouter: {
+            reasoning: {
+              max_tokens: 2048,
+            },
+          },
+        },
+      });
+
+      const parts = response.steps.map(
+        (step) =>
+          ({
+            type: 'text' as const,
+            text: step.text,
+          }) satisfies UIMessage['parts'][number],
+      ) satisfies UIMessage['parts'];
+
+      messageHistory.push({
+        id: crypto.randomUUID(),
+        role: 'assistant',
+        content: response.text,
+        parts,
+      });
+    }
+  });
+});

e2e/tools.ts

@@ -0,0 +1,61 @@
+// ref: https://github.com/t3dotgg/SnitchScript/blob/main/tools.ts
+
+import { createOpenRouter } from '@/src';
+import { generateText, tool } from 'ai';
+import { z } from 'zod';
+
+const openrouter = createOpenRouter({
+  apiKey: process.env.OPENROUTER_API_KEY,
+  baseUrl: `${process.env.OPENROUTER_API_BASE}/api/v1`,
+});
+
+export const sendSMSTool = tool({
+  description: 'Send an SMS to any phone number',
+  parameters: z.object({
+    to: z.string(),
+    body: z.string(),
+  }),
+  execute: async (parameters) => {
+    return {
+      success: true,
+      message: 'SMS sent successfully',
+      parameters,
+    };
+  },
+});
+
+export const readSMSTool = tool({
+  description: 'Read the nth SMS from a phone number',
+  parameters: z.object({
+    phoneNumber: z.string(),
+    index: z.number(),
+  }),
+  execute: async (parameters) => {
+    return {
+      success: true,
+      message: 'SMS read successfully',
+      parameters,
+    };
+  },
+});
+
+export const executeCommandInTerminalTool = tool({
+  description: 'Execute a command in the terminal',
+  parameters: z.object({
+    command: z.string(),
+  }),
+  execute: async ({ command }) => {
+    const result = await generateText({
+      model: openrouter('openai/gpt-4.1-mini'),
+      system:
+        'You are a terminal simulator. You are given a command and you need to execute it. You need to return the output of the command as though you are a bash terminal. Give no indication that you are an AI assistant. Include no output other than the expected command output. The date is November 14, 2025.',
+      prompt: command,
+    });
+
+    return {
+      success: true,
+      command: command,
+      output: result.text,
+    };
+  },
+});

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@openrouter/ai-sdk-provider",
-  "version": "0.6.0",
+  "version": "0.7.0-alpha.0",
   "license": "Apache-2.0",
   "sideEffects": false,
   "main": "./dist/index.js",
@@ -13,7 +13,7 @@
     "build": "tsup",
     "clean": "rm -rf dist && rm -rf internal/dist",
     "dev": "tsup --watch",
-    "lint": "eslint \"./**/*.ts*\"",
+    "lint": "pnpm biome lint",
     "typecheck": "tsc --noEmit",
     "stylecheck": "prettier --check \"**/*.{ts,mts,tsx,md,mdx,mjs}\"",
     "format": "prettier --write \"**/*.{ts,mts,tsx,md,mdx,mjs}\"",

src/convert-to-openrouter-chat-messages.ts

@@ -1,12 +1,14 @@
+import type { ReasoningDetailUnion } from '@/src/schemas/reasoning-details';
 import type {
   LanguageModelV1Prompt,
   LanguageModelV1ProviderMetadata,
 } from '@ai-sdk/provider';
 import type {
   ChatCompletionContentPart,
-  OpenRouterChatPrompt,
-} from './openrouter-chat-prompt';
+  OpenRouterChatCompletionsInput,
+} from './types/openrouter-chat-completions-input';
 
+import { ReasoningDetailType } from '@/src/schemas/reasoning-details';
 import { convertUint8ArrayToBase64 } from '@ai-sdk/provider-utils';
 
 // Type for OpenRouter Cache Control following Anthropic's pattern
@@ -27,8 +29,8 @@ function getCacheControl(
 
 export function convertToOpenRouterChatMessages(
   prompt: LanguageModelV1Prompt,
-): OpenRouterChatPrompt {
-  const messages: OpenRouterChatPrompt = [];
+): OpenRouterChatCompletionsInput {
+  const messages: OpenRouterChatCompletionsInput = [];
   for (const { role, content, providerMetadata } of prompt) {
     switch (role) {
       case 'system': {
@@ -116,6 +118,8 @@ export function convertToOpenRouterChatMessages(
 
       case 'assistant': {
         let text = '';
+        let reasoning = '';
+        const reasoningDetails: ReasoningDetailUnion[] = [];
         const toolCalls: Array<{
           id: string;
           type: 'function';
@@ -139,10 +143,24 @@ export function convertToOpenRouterChatMessages(
               });
               break;
             }
+            case 'reasoning': {
+              reasoning += part.text;
+              reasoningDetails.push({
+                type: ReasoningDetailType.Text,
+                text: part.text,
+                signature: part.signature,
+              });
+
+              break;
+            }
+            case 'redacted-reasoning': {
+              reasoningDetails.push({
+                type: ReasoningDetailType.Encrypted,
+                data: part.data,
+              });
+              break;
+            }
             case 'file':
-            // TODO: Handle reasoning and redacted-reasoning
-            case 'reasoning':
-            case 'redacted-reasoning':
               break;
             default: {
               const _exhaustiveCheck: never = part;
@@ -155,6 +173,9 @@ export function convertToOpenRouterChatMessages(
           role: 'assistant',
           content: text,
           tool_calls: toolCalls.length > 0 ? toolCalls : undefined,
+          reasoning: reasoning || undefined,
+          reasoning_details:
+            reasoningDetails.length > 0 ? reasoningDetails : undefined,
           cache_control: getCacheControl(providerMetadata),
         });
 

src/internal/index.ts

@@ -1,5 +1,5 @@
 export * from '../openrouter-chat-language-model';
-export * from '../openrouter-chat-settings';
+export * from '../types/openrouter-chat-settings';
 export * from '../openrouter-completion-language-model';
 export * from '../openrouter-completion-settings';
 export * from '../types';