diff --git a/assets/oh-my-opencode.schema.json b/assets/oh-my-opencode.schema.json
index be4d7a9ef..380cdcd2b 100644
--- a/assets/oh-my-opencode.schema.json
+++ b/assets/oh-my-opencode.schema.json
@@ -130,7 +130,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -196,7 +197,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -399,7 +401,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -480,7 +483,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -546,7 +550,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -749,7 +754,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -830,7 +836,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -896,7 +903,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -1099,7 +1107,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -1180,7 +1189,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -1246,7 +1256,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -1449,7 +1460,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -1533,7 +1545,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -1599,7 +1612,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -1802,7 +1816,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -1883,7 +1898,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -1949,7 +1965,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -2152,7 +2169,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -2233,7 +2251,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -2299,7 +2318,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -2502,7 +2522,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -2583,7 +2604,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -2649,7 +2671,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -2852,7 +2875,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -2933,7 +2957,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -2999,7 +3024,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -3202,7 +3228,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -3283,7 +3310,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -3349,7 +3377,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -3552,7 +3581,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -3633,7 +3663,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -3699,7 +3730,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -3902,7 +3934,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -3983,7 +4016,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -4049,7 +4083,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -4252,7 +4287,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -4333,7 +4369,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -4399,7 +4436,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -4602,7 +4640,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -4683,7 +4722,8 @@
                           "low",
                           "medium",
                           "high",
-                          "xhigh"
+                          "xhigh",
+                          "max"
                         ]
                       },
                       "temperature": {
@@ -4749,7 +4789,8 @@
                               "low",
                               "medium",
                               "high",
-                              "xhigh"
+                              "xhigh",
+                              "max"
                             ]
                           },
                           "temperature": {
@@ -4952,7 +4993,8 @@
                 "low",
                 "medium",
                 "high",
-                "xhigh"
+                "xhigh",
+                "max"
               ]
             },
             "textVerbosity": {
@@ -5044,7 +5086,8 @@
                         "low",
                         "medium",
                         "high",
-                        "xhigh"
+                        "xhigh",
+                        "max"
                       ]
                     },
                     "temperature": {
@@ -5110,7 +5153,8 @@
                             "low",
                             "medium",
                             "high",
-                            "xhigh"
+                            "xhigh",
+                            "max"
                           ]
                         },
                         "temperature": {
@@ -5199,7 +5243,8 @@
               "low",
               "medium",
               "high",
-              "xhigh"
+              "xhigh",
+              "max"
             ]
           },
           "textVerbosity": {
diff --git a/src/config/schema/agent-overrides.ts b/src/config/schema/agent-overrides.ts
index ac560cbd5..cbf995392 100644
--- a/src/config/schema/agent-overrides.ts
+++ b/src/config/schema/agent-overrides.ts
@@ -35,7 +35,7 @@ export const AgentOverrideConfigSchema = z.object({
     })
     .optional(),
   /** Reasoning effort level (OpenAI). Overrides category and default settings. */
-  reasoningEffort: z.enum(["none", "minimal", "low", "medium", "high", "xhigh"]).optional(),
+  reasoningEffort: z.enum(["none", "minimal", "low", "medium", "high", "xhigh", "max"]).optional(),
   /** Text verbosity level. */
   textVerbosity: z.enum(["low", "medium", "high"]).optional(),
   /** Provider-specific options. Passed directly to OpenCode SDK. */
diff --git a/src/config/schema/categories.ts b/src/config/schema/categories.ts
index a7ad4c0b4..4703e7079 100644
--- a/src/config/schema/categories.ts
+++ b/src/config/schema/categories.ts
@@ -16,7 +16,7 @@ export const CategoryConfigSchema = z.object({
       budgetTokens: z.number().optional(),
     })
     .optional(),
-  reasoningEffort: z.enum(["none", "minimal", "low", "medium", "high", "xhigh"]).optional(),
+  reasoningEffort: z.enum(["none", "minimal", "low", "medium", "high", "xhigh", "max"]).optional(),
   textVerbosity: z.enum(["low", "medium", "high"]).optional(),
   tools: z.record(z.string(), z.boolean()).optional(),
   prompt_append: z.string().optional(),
diff --git a/src/config/schema/fallback-models.ts b/src/config/schema/fallback-models.ts
index deca94d5f..1ad3eb960 100644
--- a/src/config/schema/fallback-models.ts
+++ b/src/config/schema/fallback-models.ts
@@ -3,7 +3,7 @@ import { z } from "zod"
 export const FallbackModelObjectSchema = z.object({
   model: z.string(),
   variant: z.string().optional(),
-  reasoningEffort: z.enum(["none", "minimal", "low", "medium", "high", "xhigh"]).optional(),
+  reasoningEffort: z.enum(["none", "minimal", "low", "medium", "high", "xhigh", "max"]).optional(),
   temperature: z.number().min(0).max(2).optional(),
   top_p: z.number().min(0).max(1).optional(),
   maxTokens: z.number().optional(),
diff --git a/src/shared/model-capability-heuristics.ts b/src/shared/model-capability-heuristics.ts
index d1eba7dd7..882fe81ec 100644
--- a/src/shared/model-capability-heuristics.ts
+++ b/src/shared/model-capability-heuristics.ts
@@ -32,7 +32,7 @@ export const HEURISTIC_MODEL_FAMILY_REGISTRY: ReadonlyArray<HeuristicModelFamily
     family: "gpt-5",
     includes: ["gpt-5"],
     variants: ["low", "medium", "high", "xhigh"],
-    reasoningEfforts: ["none", "minimal", "low", "medium", "high", "xhigh"],
+    reasoningEfforts: ["none", "minimal", "low", "medium", "high", "xhigh", "max"],
   },
   {
     family: "gpt-legacy",
diff --git a/src/shared/model-settings-compatibility.ts b/src/shared/model-settings-compatibility.ts
index 974d75619..c2354038e 100644
--- a/src/shared/model-settings-compatibility.ts
+++ b/src/shared/model-settings-compatibility.ts
@@ -32,10 +32,10 @@ export type ModelSettingsCompatibilityChange = {
   from: string
   to?: string
   reason:
-    | "unsupported-by-model-family"
-    | "unknown-model-family"
-    | "unsupported-by-model-metadata"
-    | "max-output-limit"
+  | "unsupported-by-model-family"
+  | "unknown-model-family"
+  | "unsupported-by-model-metadata"
+  | "max-output-limit"
 }
 
 export type ModelSettingsCompatibilityResult = {
@@ -49,7 +49,7 @@ export type ModelSettingsCompatibilityResult = {
 }
 
 const VARIANT_LADDER = ["low", "medium", "high", "xhigh", "max"]
-const REASONING_LADDER = ["none", "minimal", "low", "medium", "high", "xhigh"]
+const REASONING_LADDER = ["none", "minimal", "low", "medium", "high", "xhigh", "max"]
 
 function downgradeWithinLadder(value: string, allowed: string[], ladder: string[]): string | undefined {
   const requestedIndex = ladder.indexOf(value)