feat(reasoning): add max effort

Author: Tanger TAS

crates/config/src/schema.rs

@@ -62,6 +62,8 @@ pub enum ReasoningEffort {
     /// Extra-high reasoning effort. Serializes as `"xhigh"`.
     #[serde(rename = "xhigh")]
     ExtraHigh,
+    /// Maximum reasoning effort. Serializes as `"max"`.
+    Max,
 }
 
 impl ReasoningEffort {
@@ -72,6 +74,7 @@ impl ReasoningEffort {
         Self::Medium,
         Self::High,
         Self::ExtraHigh,
+        Self::Max,
     ];
 
     /// Wire / serialization name (matches serde output).
@@ -83,6 +86,7 @@ impl ReasoningEffort {
             Self::Medium => "medium",
             Self::High => "high",
             Self::ExtraHigh => "xhigh",
+            Self::Max => "max",
         }
     }
 
@@ -95,6 +99,7 @@ impl ReasoningEffort {
             Self::Medium => "Medium",
             Self::High => "High",
             Self::ExtraHigh => "Extra High",
+            Self::Max => "Max",
         }
     }
 }
@@ -109,6 +114,7 @@ impl TryFrom<&str> for ReasoningEffort {
             "medium" => Ok(Self::Medium),
             "high" => Ok(Self::High),
             "xhigh" => Ok(Self::ExtraHigh),
+            "max" => Ok(Self::Max),
             other => Err(format!("unknown reasoning effort: {other}")),
         }
     }

crates/config/src/validate/tests/agents.rs

@@ -125,7 +125,7 @@ max_iterations = 0
 
 #[test]
 fn reasoning_effort_valid_values_no_error() {
-    for effort in &["minimal", "low", "medium", "high", "xhigh"] {
+    for effort in &["minimal", "low", "medium", "high", "xhigh", "max"] {
         let toml = format!(
             r#"
             [agents.presets.thinker]

crates/providers/src/anthropic.rs

@@ -111,7 +111,7 @@ impl AnthropicProvider {
             ReasoningEffort::Low => 4096,
             ReasoningEffort::Medium => 10240,
             ReasoningEffort::High => 32768,
-            ReasoningEffort::ExtraHigh => 65536,
+            ReasoningEffort::ExtraHigh | ReasoningEffort::Max => 65536,
         };
         body["thinking"] = serde_json::json!({
             "type": "enabled",

crates/providers/src/model_id.rs

@@ -27,6 +27,7 @@ pub(crate) const REASONING_SUFFIXES: &[(&str, moltis_agents::model::ReasoningEff
         "reasoning-xhigh",
         moltis_agents::model::ReasoningEffort::ExtraHigh,
     ),
+    ("reasoning-max", moltis_agents::model::ReasoningEffort::Max),
 ];
 
 #[must_use]
@@ -106,6 +107,10 @@ mod tests {
             split_reasoning_suffix("gpt-5@reasoning-xhigh"),
             ("gpt-5", Some(ReasoningEffort::ExtraHigh))
         );
+        assert_eq!(
+            split_reasoning_suffix("gpt-5.6-sol@reasoning-max"),
+            ("gpt-5.6-sol", Some(ReasoningEffort::Max))
+        );
         assert_eq!(split_reasoning_suffix("gpt-4o"), ("gpt-4o", None));
         assert_eq!(
             split_reasoning_suffix("model@unknown-suffix"),
@@ -132,6 +137,10 @@ mod tests {
             "claude-opus-4-5"
         );
         assert_eq!(raw_model_id("o3@reasoning-medium"), "o3");
+        assert_eq!(
+            raw_model_id("openai-codex::gpt-5.6-sol@reasoning-max"),
+            "gpt-5.6-sol"
+        );
         assert_eq!(raw_model_id("gpt-4o"), "gpt-4o");
     }
 }

crates/providers/src/openai/provider/core.rs

@@ -260,7 +260,7 @@ impl OpenAiProvider {
                 | ReasoningEffort::Low
                 | ReasoningEffort::Medium
                 | ReasoningEffort::High => "high",
-                ReasoningEffort::ExtraHigh => "max",
+                ReasoningEffort::ExtraHigh | ReasoningEffort::Max => "max",
             }),
             ReasoningEffortPolicy::KimiMax => self.reasoning_effort.map(|_| "max"),
             ReasoningEffortPolicy::OpenAi => self.reasoning_effort.map(|e| match e {
@@ -274,10 +274,11 @@ impl OpenAiProvider {
                 ReasoningEffort::Low => "low",
                 ReasoningEffort::Medium => "medium",
                 ReasoningEffort::High => "high",
-                ReasoningEffort::ExtraHigh => {
+                ReasoningEffort::ExtraHigh | ReasoningEffort::Max => {
                     tracing::debug!(
                         model = %self.model,
-                        "reasoning effort ExtraHigh clamped to \"high\" (OpenAI maximum)"
+                        effort = e.as_str(),
+                        "reasoning effort clamped to \"high\" (OpenAI Chat Completions maximum)"
                     );
                     "high"
                 },

crates/providers/src/openai/provider/request.rs

@@ -958,22 +958,27 @@ mod tests {
     }
 
     #[test]
-    fn deepseek_v4_reasoning_effort_enables_thinking_and_maps_xhigh_to_max() {
-        let mut p = provider("deepseek-v4-pro", "deepseek", "https://api.deepseek.com")
-            .with_capabilities(OpenAiProviderCapabilities {
-                reasoning_effort_policy: ReasoningEffortPolicy::DeepSeek,
-                ..OpenAiProviderCapabilities::DEFAULT
+    fn deepseek_v4_reasoning_effort_enables_thinking_and_maps_top_levels_to_max() {
+        for effort in [
+            moltis_agents::model::ReasoningEffort::ExtraHigh,
+            moltis_agents::model::ReasoningEffort::Max,
+        ] {
+            let mut p = provider("deepseek-v4-pro", "deepseek", "https://api.deepseek.com")
+                .with_capabilities(OpenAiProviderCapabilities {
+                    reasoning_effort_policy: ReasoningEffortPolicy::DeepSeek,
+                    ..OpenAiProviderCapabilities::DEFAULT
+                });
+            p.reasoning_effort = Some(effort);
+            let mut body = serde_json::json!({
+                "model": "deepseek-v4-pro",
+                "messages": [{"role": "user", "content": "hello"}],
             });
-        p.reasoning_effort = Some(moltis_agents::model::ReasoningEffort::ExtraHigh);
-        let mut body = serde_json::json!({
-            "model": "deepseek-v4-pro",
-            "messages": [{"role": "user", "content": "hello"}],
-        });
 
-        p.apply_reasoning_effort_chat(&mut body);
+            p.apply_reasoning_effort_chat(&mut body);
 
-        assert_eq!(body["reasoning_effort"], "max");
-        assert_eq!(body["thinking"], serde_json::json!({ "type": "enabled" }));
+            assert_eq!(body["reasoning_effort"], "max");
+            assert_eq!(body["thinking"], serde_json::json!({ "type": "enabled" }));
+        }
     }
 
     #[test]
@@ -1002,6 +1007,7 @@ mod tests {
             moltis_agents::model::ReasoningEffort::Medium,
             moltis_agents::model::ReasoningEffort::High,
             moltis_agents::model::ReasoningEffort::ExtraHigh,
+            moltis_agents::model::ReasoningEffort::Max,
         ] {
             let mut p = provider("kimi-k3", "moonshot", "https://api.moonshot.ai/v1")
                 .with_capabilities(OpenAiProviderCapabilities {

crates/providers/src/openai_codex.rs

@@ -102,7 +102,7 @@ impl OpenAiCodexProvider {
 
     /// Add `reasoning.effort` to a Responses-API request body when an effort
     /// is configured. GPT-5 family models accept `minimal`, `low`, `medium`,
-    /// `high`, and `xhigh` (matching the official Codex client).
+    /// `high`, `xhigh`, and `max` (matching the current Codex model catalog).
     fn apply_reasoning(&self, body: &mut serde_json::Value) {
         if let Some(effort) = self.reasoning_effort {
             body["reasoning"]["effort"] = serde_json::json!(effort.as_str());
@@ -947,6 +947,7 @@ mod tests {
             (ReasoningEffort::Medium, "medium"),
             (ReasoningEffort::High, "high"),
             (ReasoningEffort::ExtraHigh, "xhigh"),
+            (ReasoningEffort::Max, "max"),
         ] {
             let mut provider = OpenAiCodexProvider::new("gpt-5.4".to_string());
             provider.reasoning_effort = Some(effort);

crates/web/ui/e2e/specs/reasoning-toggle.spec.js

@@ -64,7 +64,7 @@ test.describe("reasoning effort toggle", () => {
 		expect(pageErrors).toEqual([]);
 	});
 
-	test("clicking toggle opens dropdown with Off/Low/Medium/High options", async ({ page }) => {
+	test("clicking toggle opens dropdown with all reasoning effort options", async ({ page }) => {
 		const pageErrors = watchPageErrors(page);
 
 		await setMockModels(
@@ -81,13 +81,14 @@ test.describe("reasoning effort toggle", () => {
 		await expect(dropdown).toBeVisible();
 
 		const items = page.locator("#reasoningDropdownList .model-dropdown-item");
-		await expect(items).toHaveCount(6);
+		await expect(items).toHaveCount(7);
 		await expect(items.nth(0)).toHaveText("Off");
 		await expect(items.nth(1)).toHaveText("Minimal");
 		await expect(items.nth(2)).toHaveText("Low");
 		await expect(items.nth(3)).toHaveText("Medium");
 		await expect(items.nth(4)).toHaveText("High");
 		await expect(items.nth(5)).toHaveText("Extra High");
+		await expect(items.nth(6)).toHaveText("Max");
 
 		expect(pageErrors).toEqual([]);
 	});
@@ -141,12 +142,19 @@ test.describe("reasoning effort toggle", () => {
 			window.__chatWsSpyInstalled = true;
 		});
 
-		// Set up a reasoning model and select high effort
+		// Set up a reasoning model and select maximum effort
 		await setMockModels(
 			page,
-			[{ id: "claude-opus-4-5", displayName: "Claude Opus 4.5", provider: "anthropic", supportsReasoning: true }],
-			"claude-opus-4-5",
-			"high",
+			[
+				{
+					id: "openai-codex::gpt-5.6-sol",
+					displayName: "GPT-5.6 Sol",
+					provider: "openai-codex",
+					supportsReasoning: true,
+				},
+			],
+			"openai-codex::gpt-5.6-sol",
+			"max",
 		);
 
 		const chatInput = page.locator("#chatInput");
@@ -155,7 +163,7 @@ test.describe("reasoning effort toggle", () => {
 
 		const payloads = await page.evaluate(() => window.__chatSendPayloads);
 		expect(payloads.length).toBeGreaterThan(0);
-		expect(payloads[0].model).toBe("claude-opus-4-5@reasoning-high");
+		expect(payloads[0].model).toBe("openai-codex::gpt-5.6-sol@reasoning-max");
 
 		expect(pageErrors).toEqual([]);
 	});

crates/web/ui/src/locales/en/chat.ts

@@ -52,6 +52,7 @@ export default {
 	reasoningMedium: "Medium",
 	reasoningHigh: "High",
 	reasoningExtraHigh: "Extra High",
+	reasoningMax: "Max",
 
 	// ── Debug panel ──────────────────────────────────────────
 	debugTooltip: "Show context debug info",

crates/web/ui/src/locales/fr/chat.ts

@@ -52,6 +52,7 @@ export default {
 	reasoningMedium: "Moyen",
 	reasoningHigh: "Élevé",
 	reasoningExtraHigh: "Très élevé",
+	reasoningMax: "Maximum",
 
 	// ── Debug panel ──────────────────────────────────────────
 	debugTooltip: "Show context debug info",