chore: restructure reasoning support (#5922)

## Background
Different providers have different reasoning options that are specific
to them, e.g. Anthropic (signatures, redacted reasoning) and OpenAI
(reasoning id and parts). It is also unclear that e.g. the signature is
provider-specific.

## Summary
Replaces existing reasoning with more flexible mechanism based on
providerOptions and providerMetadata.

Author: lgrammel

.changeset/nice-tips-walk.md

@@ -0,0 +1,5 @@
+---
+'@ai-sdk/provider': major
+---
+
+chore: restructure reasoning support

examples/ai-core/src/generate-text/anthropic-reasoning-chatbot.ts

@@ -1,9 +1,21 @@
-import { anthropic, AnthropicProviderOptions } from '@ai-sdk/anthropic';
+import { createAnthropic, AnthropicProviderOptions } from '@ai-sdk/anthropic';
 import { CoreMessage, generateText } from 'ai';
 import 'dotenv/config';
 import * as readline from 'node:readline/promises';
 import { weatherTool } from '../tools/weather-tool';
 
+const anthropic = createAnthropic({
+  // example fetch wrapper that logs the input to the API call:
+  fetch: async (url, options) => {
+    console.log('URL', url);
+    console.log('Headers', JSON.stringify(options!.headers, null, 2));
+    console.log(
+      `Body ${JSON.stringify(JSON.parse(options!.body! as string), null, 2)}`,
+    );
+    return await fetch(url, options);
+  },
+});
+
 const terminal = readline.createInterface({
   input: process.stdin,
   output: process.stdout,

examples/ai-core/src/stream-text/amazon-bedrock-fullstream.ts

@@ -25,13 +25,11 @@ async function main() {
   for await (const part of result.fullStream) {
     switch (part.type) {
       case 'reasoning': {
-        if (part.reasoningType === 'text') {
-          if (!enteredReasoning) {
-            enteredReasoning = true;
-            console.log('\nREASONING:\n');
-          }
-          process.stdout.write(part.text);
+        if (!enteredReasoning) {
+          enteredReasoning = true;
+          console.log('\nREASONING:\n');
         }
+        process.stdout.write(part.text);
         break;
       }
 

examples/ai-core/src/stream-text/amazon-bedrock-reasoning-chatbot.ts

@@ -60,13 +60,8 @@ async function main() {
 
     process.stdout.write('\nAssistant: ');
     for await (const part of result.fullStream) {
-      if (part.type === 'reasoning' && part.reasoningType === 'text') {
+      if (part.type === 'reasoning') {
         process.stdout.write('\x1b[34m' + part.text + '\x1b[0m');
-      } else if (
-        part.type === 'reasoning' &&
-        part.reasoningType === 'redacted'
-      ) {
-        process.stdout.write('\x1b[31m' + '<redacted>' + '\x1b[0m');
       } else if (part.type === 'text') {
         process.stdout.write(part.text);
       }

examples/ai-core/src/stream-text/amazon-bedrock-reasoning-fullstream.ts

@@ -27,13 +27,11 @@ async function main() {
   for await (const part of result.fullStream) {
     switch (part.type) {
       case 'reasoning': {
-        if (part.reasoningType === 'text') {
-          if (!enteredReasoning) {
-            enteredReasoning = true;
-            console.log('\nREASONING:\n');
-          }
-          process.stdout.write(part.text);
+        if (!enteredReasoning) {
+          enteredReasoning = true;
+          console.log('\nREASONING:\n');
         }
+        process.stdout.write(part.text);
         break;
       }
 

examples/ai-core/src/stream-text/amazon-bedrock-reasoning.ts

@@ -20,10 +20,8 @@ async function main() {
   });
 
   for await (const part of result.fullStream) {
-    if (part.type === 'reasoning' && part.reasoningType === 'text') {
+    if (part.type === 'reasoning') {
       process.stdout.write('\x1b[34m' + part.text + '\x1b[0m');
-    } else if (part.type === 'reasoning' && part.reasoningType === 'redacted') {
-      process.stdout.write('\x1b[31m' + '<redacted>' + '\x1b[0m');
     } else if (part.type === 'text') {
       process.stdout.write(part.text);
     }

examples/ai-core/src/stream-text/anthropic-reasoning-chatbot.ts

@@ -60,13 +60,8 @@ async function main() {
 
     process.stdout.write('\nAssistant: ');
     for await (const part of result.fullStream) {
-      if (part.type === 'reasoning' && part.reasoningType === 'text') {
+      if (part.type === 'reasoning') {
         process.stdout.write('\x1b[34m' + part.text + '\x1b[0m');
-      } else if (
-        part.type === 'reasoning' &&
-        part.reasoningType === 'redacted'
-      ) {
-        process.stdout.write('\x1b[31m' + '<redacted>' + '\x1b[0m');
       } else if (part.type === 'text') {
         process.stdout.write(part.text);
       }

examples/ai-core/src/stream-text/anthropic-reasoning-fullstream.ts

@@ -36,13 +36,11 @@ async function main() {
   for await (const part of result.fullStream) {
     switch (part.type) {
       case 'reasoning': {
-        if (part.reasoningType === 'text') {
-          if (!enteredReasoning) {
-            enteredReasoning = true;
-            console.log('\nREASONING:\n');
-          }
-          process.stdout.write(part.text);
+        if (!enteredReasoning) {
+          enteredReasoning = true;
+          console.log('\nREASONING:\n');
         }
+        process.stdout.write(part.text);
         break;
       }
 

examples/ai-core/src/stream-text/anthropic-reasoning.ts

@@ -19,10 +19,12 @@ async function main() {
   });
 
   for await (const part of result.fullStream) {
-    if (part.type === 'reasoning' && part.reasoningType === 'text') {
+    if (part.type === 'reasoning') {
       process.stdout.write('\x1b[34m' + part.text + '\x1b[0m');
-    } else if (part.type === 'reasoning' && part.reasoningType === 'redacted') {
-      process.stdout.write('\x1b[31m' + '<redacted>' + '\x1b[0m');
+
+      if (part.providerMetadata?.anthropic?.redactedData != null) {
+        process.stdout.write('\x1b[31m' + '<redacted>' + '\x1b[0m');
+      }
     } else if (part.type === 'text') {
       process.stdout.write(part.text);
     }

examples/ai-core/src/stream-text/deepseek-reasoning.ts

@@ -9,7 +9,7 @@ async function main() {
   });
 
   for await (const part of result.fullStream) {
-    if (part.type === 'reasoning' && part.reasoningType === 'text') {
+    if (part.type === 'reasoning') {
       process.stdout.write('\x1b[34m' + part.text + '\x1b[0m');
     } else if (part.type === 'text') {
       process.stdout.write(part.text);