Add tri-state reasoning overrides

types.go

@@ -299,12 +299,12 @@ type ExecutionTarget struct {
 // ExecutionTargetOverride represents per-request runtime setting overrides and
 // has no stable JSON representation.
 //
-// Non-empty string fields replace profile and backend values. Non-nil numeric
-// pointers replace profile values and preserve explicit zero. A non-empty
-// ExtraParams map replaces the complete profile or backend map rather than
-// merging keys. Empty string fields, nil pointers, and a nil or empty
-// ExtraParams map inherit the selected profile over its backend, when any, and
-// framework defaults.
+// Non-empty string fields replace profile and backend values. Non-nil pointer
+// fields replace profile values and preserve explicit zero or empty values. A
+// non-empty ExtraParams map replaces the complete profile or backend map
+// rather than merging keys. Empty string fields, nil pointers, and a nil or
+// empty ExtraParams map inherit the selected profile over its backend, when
+// any, and framework defaults.
 type ExecutionTargetOverride struct {
 	// Endpoint replaces the profile or backend endpoint when non-empty without
 	// changing the effective BackendID.
@@ -322,9 +322,11 @@ type ExecutionTargetOverride struct {
 	TimeoutSeconds *int
 	// ServiceTier replaces the profile value when non-blank.
 	ServiceTier string
-	// ReasoningEffort replaces the profile value when non-blank. An empty value
-	// cannot clear a profile setting.
-	ReasoningEffort string
+	// ReasoningEffort controls the per-run reasoning setting. Nil inherits the
+	// profile value. A pointer to a non-blank string trims and replaces the
+	// profile value. A pointer to an empty or whitespace-only string clears the
+	// inherited value and disables reasoning for this run.
+	ReasoningEffort *string
 	// APIKeyEnv replaces the profile or backend environment-variable name when
 	// non-blank. A direct RunRequest.APIKey still takes precedence over
 	// environment lookup.