diff --git a/.changeset/claude-code-side-effects.md b/.changeset/claude-code-side-effects.md
new file mode 100644
index 0000000000..5a522f13a4
--- /dev/null
+++ b/.changeset/claude-code-side-effects.md
@@ -0,0 +1,5 @@
+---
+'@tanstack/ai-claude-code': patch
+---
+
+`@tanstack/ai-claude-code` now sets `"sideEffects": false`. When an app imports only `translateSdkStream`, a bundler can drop the unused adapter modules.
diff --git a/packages/ai-claude-code/package.json b/packages/ai-claude-code/package.json
index fa5f6e156d..2e4e8e349a 100644
--- a/packages/ai-claude-code/package.json
+++ b/packages/ai-claude-code/package.json
@@ -36,6 +36,7 @@
       "import": "./dist/esm/byok.js"
     }
   },
+  "sideEffects": false,
   "files": [
     "dist",
     "src"