diff --git a/.github/workflows/eval-guidance.yml b/.github/workflows/eval-guidance.yml
index 6f0baf259c..0c637e0d0c 100644
--- a/.github/workflows/eval-guidance.yml
+++ b/.github/workflows/eval-guidance.yml
@@ -4,8 +4,6 @@ on:
   pull_request:
     paths:
       - 'packages/core/src/**/*.ts'
-      - '.gemini/commands/*.toml'
-      - '.gemini/skills/**/SKILL.md'
       - '!**/*.test.ts'
       - '!**/*.test.tsx'
 
@@ -29,33 +27,8 @@ jobs:
         env:
           GH_TOKEN: '${{ secrets.GITHUB_TOKEN }}'
         run: |
-          # 1. Path-based detection (The "Knowns")
-          KNOWN_PATHS=("packages/core/src/prompts/snippets" "packages/core/src/tools/definitions" ".gemini/commands" ".gemini/skills")
-          PR_FILES=$(git diff --name-only origin/${{ github.base_ref }}...HEAD)
-
-          IS_STEERING_CHANGE=false
-          for path in "${KNOWN_PATHS[@]}"; do
-            if echo "$PR_FILES" | grep -q "$path"; then
-              IS_STEERING_CHANGE=true
-              break
-            fi
-          done
-
-          # 2. Signature-based detection (The "Unknowns")
-          # We look for patterns that define tools or agents in any file
-          SIGNATURES=("LocalAgentDefinition" "LocalInvocation" "ToolDefinition" "inputSchema" "kind: 'local'")
-          if [ "$IS_STEERING_CHANGE" = false ]; then
-            PR_DIFF=$(git diff -U0 origin/${{ github.base_ref }}...HEAD)
-            for sig in "${SIGNATURES[@]}"; do
-              if echo "$PR_DIFF" | grep -q "$sig"; then
-                IS_STEERING_CHANGE=true
-                echo "DEBUG: Detected steering via signature: $sig"
-                break
-              fi
-            done
-          fi
-
-          echo "STEERING_DETECTED=$IS_STEERING_CHANGE" >> "$GITHUB_OUTPUT"
+          STEERING_DETECTED=$(node scripts/changed_prompt.js --steering-only)
+          echo "STEERING_DETECTED=$STEERING_DETECTED" >> "$GITHUB_OUTPUT"
 
       - name: 'Analyze PR Content'
         if: "steps.detect.outputs.STEERING_DETECTED == 'true'"
diff --git a/scripts/changed_prompt.js b/scripts/changed_prompt.js
index 0ad0e365f7..22563810e4 100644
--- a/scripts/changed_prompt.js
+++ b/scripts/changed_prompt.js
@@ -5,14 +5,26 @@
  */
 import { execSync } from 'node:child_process';
 
-const EVALS_FILE_PREFIXES = [
+const CORE_STEERING_PATHS = [
   'packages/core/src/prompts/',
   'packages/core/src/tools/',
-  'evals/',
+];
+
+const TEST_PATHS = ['evals/'];
+
+const STEERING_SIGNATURES = [
+  'LocalAgentDefinition',
+  'LocalInvocation',
+  'ToolDefinition',
+  'inputSchema',
+  "kind: 'local'",
 ];
 
 function main() {
   const targetBranch = process.env.GITHUB_BASE_REF || 'main';
+  const verbose = process.argv.includes('--verbose');
+  const steeringOnly = process.argv.includes('--steering-only');
+
   try {
     const remoteUrl = process.env.GITHUB_REPOSITORY
       ? `https://github.com/${process.env.GITHUB_REPOSITORY}.git`
@@ -30,18 +42,60 @@ function main() {
       .split('\n')
       .filter(Boolean);
 
-    const shouldRun = changedFiles.some((file) =>
-      EVALS_FILE_PREFIXES.some((prefix) => file.startsWith(prefix)),
-    );
+    let detected = false;
+    const reasons = [];
 
-    console.log(shouldRun ? 'true' : 'false');
+    // 1. Path-based detection
+    for (const file of changedFiles) {
+      if (CORE_STEERING_PATHS.some((prefix) => file.startsWith(prefix))) {
+        detected = true;
+        reasons.push(`Matched core steering path: ${file}`);
+        if (!verbose) break;
+      }
+      if (
+        !steeringOnly &&
+        TEST_PATHS.some((prefix) => file.startsWith(prefix))
+      ) {
+        detected = true;
+        reasons.push(`Matched test path: ${file}`);
+        if (!verbose) break;
+      }
+    }
+
+    // 2. Signature-based detection (only in packages/core/src/ and only if not already detected or if verbose)
+    if (!detected || verbose) {
+      const coreChanges = changedFiles.filter((f) =>
+        f.startsWith('packages/core/src/'),
+      );
+      if (coreChanges.length > 0) {
+        // Get the actual diff content for core files
+        const diff = execSync(
+          `git diff -U0 FETCH_HEAD...HEAD -- packages/core/src/`,
+          { encoding: 'utf-8' },
+        );
+        for (const sig of STEERING_SIGNATURES) {
+          if (diff.includes(sig)) {
+            detected = true;
+            reasons.push(`Matched steering signature in core: ${sig}`);
+            if (!verbose) break;
+          }
+        }
+      }
+    }
+
+    if (verbose && reasons.length > 0) {
+      process.stderr.write('Detection reasons:\n');
+      reasons.forEach((r) => process.stderr.write(` - ${r}\n`));
+    }
+
+    process.stdout.write(detected ? 'true' : 'false');
   } catch (error) {
-    // If anything fails (e.g., no git history), run evals to be safe
-    console.warn(
-      'Warning: Failed to determine if evals should run. Defaulting to true.',
+    // If anything fails (e.g., no git history), run evals/guidance to be safe
+    process.stderr.write(
+      'Warning: Failed to determine if changes occurred. Defaulting to true.\n',
     );
-    console.error(error);
-    console.log('true');
+    process.stderr.write(String(error) + '\n');
+    process.stdout.write('true');
   }
 }