diff --git a/.github/scripts/trunk-impacted-targets.js b/.github/scripts/trunk-impacted-targets.js
index 4f4bf9de3cac..778461fbe882 100644
--- a/.github/scripts/trunk-impacted-targets.js
+++ b/.github/scripts/trunk-impacted-targets.js
@@ -174,10 +174,21 @@ function isTripwire(file) {
     return TRIPWIRE_MATCHERS.some((re) => re.test(file))
 }
 
+// Tool caches share the directory with the products, so a local run can pick up
+// directories such as .ruff_cache, .pytest_cache, and __pycache__ as products and
+// invent a lane for each. CI never sees them because a fresh checkout has only
+// tracked directories and this job does not run Python, so this keeps a local run
+// consistent with CI rather than fixing a live miscount. Dropping a real product
+// would only ever widen, because an unrecognized product name falls through to
+// ALL, so the filter is safe in the one direction it can be wrong.
+function isProductDirectory(name) {
+    return !name.startsWith('.') && !name.startsWith('__') && name !== 'node_modules'
+}
+
 function listProducts(repoRoot) {
     return fs
         .readdirSync(path.join(repoRoot, 'products'), { withFileTypes: true })
-        .filter((entry) => entry.isDirectory())
+        .filter((entry) => entry.isDirectory() && isProductDirectory(entry.name))
         .map((entry) => entry.name)
         .sort()
 }
@@ -275,8 +286,7 @@ function compileContractMatcher(inputs) {
     if (include.length === 0) {
         return null
     }
-    return (relativePath) =>
-        include.some((re) => re.test(relativePath)) && !exclude.some((re) => re.test(relativePath))
+    return (relativePath) => include.some((re) => re.test(relativePath)) && !exclude.some((re) => re.test(relativePath))
 }
 
 // Only products that narrow `backend:contract-check` in their own turbo.json get
@@ -763,6 +773,7 @@ module.exports = {
     buildContext,
     compileContractMatcher,
     globToRegExp,
+    isProductDirectory,
     isTripwire,
     parseCrateDependencies,
     parseCrateName,
diff --git a/.github/scripts/trunk-impacted-targets.test.js b/.github/scripts/trunk-impacted-targets.test.js
index c366416e291d..69ba37bef0f5 100644
--- a/.github/scripts/trunk-impacted-targets.test.js
+++ b/.github/scripts/trunk-impacted-targets.test.js
@@ -14,6 +14,7 @@ const {
     computeTargets,
     compileContractMatcher,
     globToRegExp,
+    isProductDirectory,
     isTripwire,
     parseCrateDependencies,
     reverseClosure,
@@ -301,6 +302,18 @@ test('product frontend and backend changes land in separate domains', () => {
     assert.deepEqual(computeTargets(['products/beta/backend/api.py'], CONTEXT), ['py:product:beta'])
 })
 
+// ruff and pytest leave caches next to the products, and a run that treats them
+// as products invents a lane per cache. Nothing downstream rejects a nonsense
+// target name, so the only symptom is a local run disagreeing with CI.
+test('tool caches beside the products are not products', () => {
+    for (const name of ['.ruff_cache', '.pytest_cache', '__pycache__', 'node_modules']) {
+        assert.equal(isProductDirectory(name), false, name)
+    }
+    for (const name of ['surveys', 'error_tracking', 'desktop']) {
+        assert.equal(isProductDirectory(name), true, name)
+    }
+})
+
 test('a product file that is neither backend nor frontend claims both domains', () => {
     const targets = computeTargets(['products/beta/mcp/tools.yaml'], CONTEXT)
     assert.equal(targets.includes('py:product:beta'), true)