fix(ai): handle redacted_thinking blocks, skip interleaved beta for adaptive models, drop temperature with thinking

- Map redacted_thinking to ThinkingContent with redacted: true instead of
  adding a new content type. The opaque payload goes in thinkingSignature,
  thinking text is set to "[Reasoning redacted]" so it renders naturally
  everywhere. Cross-model transform drops redacted blocks.
- Skip interleaved-thinking-2025-05-14 beta header for Opus 4.6 / Sonnet 4.6
  where adaptive thinking makes it deprecated/redundant.
- Do not send temperature when thinkingEnabled is true (incompatible with
  both adaptive and budget-based thinking).

Based on #1665 by @tctev

packages/ai/CHANGELOG.md

@@ -6,6 +6,9 @@
 
 - Restored built-in OAuth providers when unregistering dynamically registered provider IDs and added `resetOAuthProviders()` for registry reset flows.
 - Fixed Z.ai thinking control using wrong parameter name (`thinking` instead of `enable_thinking`), causing thinking to always be enabled and wasting tokens/latency ([#1674](https://github.com/badlogic/pi-mono/pull/1674) by [@okuyam2y](https://github.com/okuyam2y))
+- Fixed `redacted_thinking` blocks being silently dropped during Anthropic streaming. They are now captured as `ThinkingContent` with `redacted: true`, passed back to the API in multi-turn conversations, and handled in cross-model message transformation ([#1665](https://github.com/badlogic/pi-mono/pull/1665) by [@tctev](https://github.com/tctev))
+- Fixed `interleaved-thinking-2025-05-14` beta header being sent for adaptive thinking models (Opus 4.6, Sonnet 4.6) where the header is deprecated or redundant ([#1665](https://github.com/badlogic/pi-mono/pull/1665) by [@tctev](https://github.com/tctev))
+- Fixed temperature being sent alongside extended thinking, which is incompatible with both adaptive and budget-based thinking modes ([#1665](https://github.com/badlogic/pi-mono/pull/1665) by [@tctev](https://github.com/tctev))
 
 ## [0.55.1] - 2026-02-26
 

packages/ai/src/providers/anthropic.ts

@@ -273,6 +273,16 @@ export const streamAnthropic: StreamFunction<"anthropic-messages", AnthropicOpti
 						};
 						output.content.push(block);
 						stream.push({ type: "thinking_start", contentIndex: output.content.length - 1, partial: output });
+					} else if (event.content_block.type === "redacted_thinking") {
+						const block: Block = {
+							type: "thinking",
+							thinking: "[Reasoning redacted]",
+							thinkingSignature: event.content_block.data,
+							redacted: true,
+							index: event.index,
+						};
+						output.content.push(block);
+						stream.push({ type: "thinking_start", contentIndex: output.content.length - 1, partial: output });
 					} else if (event.content_block.type === "tool_use") {
 						const block: Block = {
 							type: "toolCall",
@@ -496,10 +506,14 @@ function createClient(
 	optionsHeaders?: Record<string, string>,
 	dynamicHeaders?: Record<string, string>,
 ): { client: Anthropic; isOAuthToken: boolean } {
+	// Adaptive thinking models (Opus 4.6, Sonnet 4.6) have interleaved thinking built-in.
+	// The beta header is deprecated on Opus 4.6 and redundant on Sonnet 4.6, so skip it.
+	const needsInterleavedBeta = interleavedThinking && !supportsAdaptiveThinking(model.id);
+
 	// Copilot: Bearer auth, selective betas (no fine-grained-tool-streaming)
 	if (model.provider === "github-copilot") {
 		const betaFeatures: string[] = [];
-		if (interleavedThinking) {
+		if (needsInterleavedBeta) {
 			betaFeatures.push("interleaved-thinking-2025-05-14");
 		}
 
@@ -524,7 +538,7 @@ function createClient(
 	}
 
 	const betaFeatures = ["fine-grained-tool-streaming-2025-05-14"];
-	if (interleavedThinking) {
+	if (needsInterleavedBeta) {
 		betaFeatures.push("interleaved-thinking-2025-05-14");
 	}
 
@@ -611,7 +625,8 @@ function buildParams(
 		];
 	}
 
-	if (options?.temperature !== undefined) {
+	// Temperature is incompatible with extended thinking (adaptive or budget-based).
+	if (options?.temperature !== undefined && !options?.thinkingEnabled) {
 		params.temperature = options.temperature;
 	}
 
@@ -723,6 +738,14 @@ function convertMessages(
 						text: sanitizeSurrogates(block.text),
 					});
 				} else if (block.type === "thinking") {
+					// Redacted thinking: pass the opaque payload back as redacted_thinking
+					if (block.redacted) {
+						blocks.push({
+							type: "redacted_thinking",
+							data: block.thinkingSignature!,
+						});
+						continue;
+					}
 					if (block.thinking.trim().length === 0) continue;
 					// If thinking signature is missing/empty (e.g., from aborted stream),
 					// convert to plain text block without <thinking> tags to avoid API rejection

packages/ai/src/providers/transform-messages.ts

@@ -39,6 +39,11 @@ export function transformMessages<TApi extends Api>(
 
 			const transformedContent = assistantMsg.content.flatMap((block) => {
 				if (block.type === "thinking") {
+					// Redacted thinking is opaque encrypted content, only valid for the same model.
+					// Drop it for cross-model to avoid API errors.
+					if (block.redacted) {
+						return isSameModel ? block : [];
+					}
 					// For same model: keep thinking blocks with signatures (needed for replay)
 					// even if the thinking text is empty (OpenAI encrypted reasoning)
 					if (isSameModel && block.thinkingSignature) return block;

packages/ai/src/types.ts

@@ -128,6 +128,10 @@ export interface ThinkingContent {
 	type: "thinking";
 	thinking: string;
 	thinkingSignature?: string; // e.g., for OpenAI responses, the reasoning item ID
+	/** When true, the thinking content was redacted by safety filters. The opaque
+	 *  encrypted payload is stored in `thinkingSignature` so it can be passed back
+	 *  to the API for multi-turn continuity. */
+	redacted?: boolean;
 }
 
 export interface ImageContent {