diff --git a/src/utils/model/modelSupportOverrides.ts b/src/utils/model/modelSupportOverrides.ts
index 56cb2519..a0460ba7 100644
--- a/src/utils/model/modelSupportOverrides.ts
+++ b/src/utils/model/modelSupportOverrides.ts
@@ -23,6 +23,17 @@ const TIERS = [
   },
 ] as const
 
+/**
+ * Strip [1m]/[2m] context-window suffixes so capability overrides match
+ * regardless of whether the runtime model name includes the suffix.
+ * The suffix is a client-side marker (never sent to the API) but the
+ * pinned env var may carry it, while the runtime model passed to
+ * modelSupportsThinking/modelSupportsEffort may not.
+ */
+function stripContextSuffix(model: string): string {
+  return model.replace(/\[(1|2)m\]/gi, '')
+}
+
 /**
  * Check whether a 3p model capability override is set for a model that matches one of
  * the pinned ANTHROPIC_DEFAULT_*_MODEL env vars.
@@ -32,12 +43,12 @@ export const get3PModelCapabilityOverride = memoize(
     if (getAPIProvider() === 'firstParty' && isFirstPartyAnthropicBaseUrl()) {
       return undefined
     }
-    const m = model.toLowerCase()
+    const m = stripContextSuffix(model.toLowerCase())
     for (const tier of TIERS) {
       const pinned = process.env[tier.modelEnvVar]
       const capabilities = process.env[tier.capabilitiesEnvVar]
       if (!pinned || capabilities === undefined) continue
-      if (m !== pinned.toLowerCase()) continue
+      if (m !== stripContextSuffix(pinned.toLowerCase())) continue
       return capabilities
         .toLowerCase()
         .split(',')
@@ -46,5 +57,5 @@ export const get3PModelCapabilityOverride = memoize(
     }
     return undefined
   },
-  (model, capability) => `${model.toLowerCase()}:${capability}`,
+  (model, capability) => `${stripContextSuffix(model.toLowerCase())}:${capability}`,
 )