feat(bot): add actions spend metric script (#26463)

tools/gemini-cli-bot/brain/metrics.md

@@ -47,6 +47,10 @@ synchronize with previous sessions:
   than closure rates).
 - **Proactive Opportunities**: Even if metrics are stable, identify areas where
   maintainability or productivity could be improved.
+- **Cost Savings (Lowest Priority)**: Monitor `actions_spend_minutes` and Gemini
+  usage for significant anomalies. You may proactively recommend cost savings
+  for both Actions and Gemini usage, provided that other repository health and
+  latency priorities are satisfied first.
 
 ### 2. Hypothesis Testing & Deep Dive
 

tools/gemini-cli-bot/metrics/scripts/actions_spend.ts

@@ -0,0 +1,125 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { execFileSync } from 'node:child_process';
+
+async function getWorkflowMinutes(): Promise<Record<string, number>> {
+  const sevenDaysAgoDate = new Date(Date.now() - 7 * 24 * 60 * 60 * 1000)
+    .toISOString()
+    .split('T')[0];
+
+  const output = execFileSync(
+    'gh',
+    [
+      'run',
+      'list',
+      '--limit',
+      '1000',
+      '--created',
+      `>=${sevenDaysAgoDate}`,
+      '--json',
+      'databaseId,workflowName',
+    ],
+    { encoding: 'utf-8' },
+  );
+
+  const runs = JSON.parse(output);
+  const workflowMinutes: Record<string, number> = {};
+  const token = execFileSync('gh', ['auth', 'token'], {
+    encoding: 'utf-8',
+  }).trim();
+  const repoInfo = JSON.parse(
+    execFileSync('gh', ['repo', 'view', '--json', 'nameWithOwner'], {
+      encoding: 'utf-8',
+    }),
+  );
+  const repoName = repoInfo.nameWithOwner;
+
+  const chunkSize = 20;
+  for (let i = 0; i < runs.length; i += chunkSize) {
+    const chunk = runs.slice(i, i + chunkSize);
+    await Promise.all(
+      chunk.map(async (r: { databaseId: number; workflowName?: string }) => {
+        try {
+          const res = await fetch(
+            `https://api.github.com/repos/${repoName}/actions/runs/${r.databaseId}/jobs`,
+            {
+              headers: {
+                Authorization: `Bearer ${token}`,
+                Accept: 'application/vnd.github.v3+json',
+              },
+            },
+          );
+
+          if (!res.ok) return;
+
+          const { jobs } = await res.json();
+          let runBillableMinutes = 0;
+
+          for (const job of jobs || []) {
+            if (!job.started_at || !job.completed_at) continue;
+            const start = new Date(job.started_at).getTime();
+            const end = new Date(job.completed_at).getTime();
+            const durationMs = end - start;
+
+            if (durationMs > 0) {
+              runBillableMinutes += Math.ceil(durationMs / (1000 * 60));
+            }
+          }
+
+          if (runBillableMinutes > 0) {
+            const name = r.workflowName || 'Unknown';
+            workflowMinutes[name] =
+              (workflowMinutes[name] || 0) + runBillableMinutes;
+          }
+        } catch {
+          // Ignore failures for individual runs
+        }
+      }),
+    );
+  }
+
+  return workflowMinutes;
+}
+
+async function run() {
+  try {
+    const workflowMinutes = await getWorkflowMinutes();
+    let totalMinutes = 0;
+
+    for (const minutes of Object.values(workflowMinutes)) {
+      totalMinutes += minutes;
+    }
+
+    const now = new Date().toISOString();
+    console.log(
+      JSON.stringify({
+        metric: 'actions_spend_minutes',
+        value: totalMinutes,
+        timestamp: now,
+        details: workflowMinutes,
+      }),
+    );
+
+    for (const [name, minutes] of Object.entries(workflowMinutes)) {
+      const safeName = name.replace(/[^a-zA-Z0-9]/g, '_').toLowerCase();
+      console.log(
+        JSON.stringify({
+          metric: `actions_spend_minutes_workflow:${safeName}`,
+          value: minutes,
+          timestamp: now,
+        }),
+      );
+    }
+  } catch (error) {
+    process.stderr.write(
+      error instanceof Error ? error.message : String(error),
+    );
+    process.exit(1);
+  }
+}
+
+run();