fix(opencode): correct prefix selection for amazon-bedrock provider in getSmallModel (#12281)

1 files changed, 26 insertions, 2 deletions

diff --git a/packages/opencode/src/provider/provider.ts b/packages/opencode/src/provider/provider.ts
index 614d4ec14..5da273fea 100644
--- a/packages/opencode/src/provider/provider.ts
+++ b/packages/opencode/src/provider/provider.ts
@@ -1171,8 +1171,32 @@ export namespace Provider {
         priority = ["gpt-5-mini", "claude-haiku-4.5", ...priority]
       }
       for (const item of priority) {
-        for (const model of Object.keys(provider.models)) {
-          if (model.includes(item)) return getModel(providerID, model)
+        if (providerID === "amazon-bedrock") {
+          const crossRegionPrefixes = ["global.", "us.", "eu."]
+          const candidates = Object.keys(provider.models).filter(m => m.includes(item))
+
+          // Model selection priority:
+          // 1. global. prefix (works everywhere)
+          // 2. User's region prefix (us., eu.)
+          // 3. Unprefixed model
+          const globalMatch = candidates.find(m => m.startsWith("global."))
+          if (globalMatch) return getModel(providerID, globalMatch)
+
+          const region = provider.options?.region
+          if (region) {
+            const regionPrefix = region.split("-")[0]
+            if (regionPrefix === "us" || regionPrefix === "eu") {
+              const regionalMatch = candidates.find(m => m.startsWith(`${regionPrefix}.`))
+              if (regionalMatch) return getModel(providerID, regionalMatch)
+            }
+          }
+
+          const unprefixed = candidates.find(m => !crossRegionPrefixes.some(p => m.startsWith(p)))
+          if (unprefixed) return getModel(providerID, unprefixed)
+        } else {
+          for (const model of Object.keys(provider.models)) {
+            if (model.includes(item)) return getModel(providerID, model)
+          }
         }
       }
     }