diff --git a/apps/mcp-server/tsup.config.ts b/apps/mcp-server/tsup.config.ts
index 260960f..4ff6c07 100644
--- a/apps/mcp-server/tsup.config.ts
+++ b/apps/mcp-server/tsup.config.ts
@@ -1,5 +1,8 @@
 import { defineConfig } from "tsup";
 
+/** `yaml` uses dynamic require internally and breaks when inlined into ESM. */
+const bundledDatabaseExternals = ["yaml"] as const;
+
 export default defineConfig({
   entry: ["src/index.ts"],
   format: ["esm"],
@@ -9,6 +12,7 @@ export default defineConfig({
   // at import time — Node 20 cannot load .ts. Third-party deps stay external
   // and are installed via the regular node_modules layer in the runtime image.
   noExternal: [/^@tasks\//],
+  external: [...bundledDatabaseExternals],
   target: "node20",
   platform: "node",
   clean: true,
diff --git a/apps/orchestrator/tsup.config.ts b/apps/orchestrator/tsup.config.ts
index 9a20f39..db7caf3 100644
--- a/apps/orchestrator/tsup.config.ts
+++ b/apps/orchestrator/tsup.config.ts
@@ -1,10 +1,13 @@
 import { defineConfig } from "tsup";
 
+const bundledDatabaseExternals = ["yaml"] as const;
+
 export default defineConfig({
   entry: ["src/index.ts"],
   format: ["esm"],
   dts: true,
   noExternal: [/^@tasks\//],
+  external: [...bundledDatabaseExternals],
   target: "node20",
   platform: "node",
   clean: true,
diff --git a/apps/worker/tsup.config.ts b/apps/worker/tsup.config.ts
index 9a20f39..db7caf3 100644
--- a/apps/worker/tsup.config.ts
+++ b/apps/worker/tsup.config.ts
@@ -1,10 +1,13 @@
 import { defineConfig } from "tsup";
 
+const bundledDatabaseExternals = ["yaml"] as const;
+
 export default defineConfig({
   entry: ["src/index.ts"],
   format: ["esm"],
   dts: true,
   noExternal: [/^@tasks\//],
+  external: [...bundledDatabaseExternals],
   target: "node20",
   platform: "node",
   clean: true,