Fix reasoning disabled by default for all providers

Previously, when reasoning was not specified, some providers like Gemini
with 'dynamic thinking' enabled by default would still use thinking.
Now explicitly sets thinkingEnabled: false (Anthropic) and
thinking: { enabled: false } (Google) when reasoning is undefined.

Closes #180

packages/ai/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- **Reasoning disabled by default**: When `reasoning` option is not specified, thinking is now explicitly disabled for all providers. Previously, some providers like Gemini with "dynamic thinking" would use their default (thinking ON), causing unexpected token usage. This was the original intended behavior. ([#180](https://github.com/badlogic/pi-mono/pull/180) by [@markusylisiurunen](https://github.com/markusylisiurunen))
+
 ## [0.22.2] - 2025-12-15
 
 ### Added

packages/ai/src/stream.ts

@@ -133,7 +133,10 @@ function mapOptionsForApi<TApi extends Api>(
 
 	switch (model.api) {
 		case "anthropic-messages": {
-			if (!options?.reasoning) return base satisfies AnthropicOptions;
+			// Explicitly disable thinking when reasoning is not specified
+			if (!options?.reasoning) {
+				return { ...base, thinkingEnabled: false } satisfies AnthropicOptions;
+			}
 
 			const anthropicBudgets = {
 				minimal: 1024,
@@ -162,7 +165,11 @@ function mapOptionsForApi<TApi extends Api>(
 			} satisfies OpenAIResponsesOptions;
 
 		case "google-generative-ai": {
-			if (!options?.reasoning) return base as any;
+			// Explicitly disable thinking when reasoning is not specified
+			// This is needed because Gemini has "dynamic thinking" enabled by default
+			if (!options?.reasoning) {
+				return { ...base, thinking: { enabled: false } } satisfies GoogleOptions;
+			}
 
 			const googleModel = model as Model<"google-generative-ai">;
 			const effort = clampReasoning(options.reasoning)!;

packages/coding-agent/CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Fixed
 
 - Improved RGB to 256-color mapping for terminals without truecolor support. Now correctly uses grayscale ramp for neutral colors and preserves semantic tints (green for success, red for error, blue for pending) instead of mapping everything to wrong cube colors.
+- `/think off` now actually disables thinking for all providers. Previously, providers like Gemini with "dynamic thinking" enabled by default would still use thinking even when turned off. ([#180](https://github.com/badlogic/pi-mono/pull/180) by [@markusylisiurunen](https://github.com/markusylisiurunen))
 
 ## [0.22.2] - 2025-12-15