Fix Windows-unsafe artifact filenames and enforce safe timestamp format

scripts/agent/run-scheduler-cycle.mjs

@@ -889,6 +889,7 @@ async function main() {
     schedulerRunState.lock_deferral = null;
     await writeRunState(runStatePath, schedulerRunState);
     const runArtifactSince = new Date().toISOString();
+    const runArtifactTimestamp = ts();
     const runStartMs = Date.parse(runArtifactSince);
     const outputChunks = [];
 
@@ -904,6 +905,7 @@ async function main() {
       SCHEDULER_CADENCE: cadence,
       SCHEDULER_PROMPT_PATH: promptPath,
       SCHEDULER_MEMORY_FILE: memoryFile,
+      SCHEDULER_RUN_TIMESTAMP: runArtifactTimestamp,
     };
 
     if (schedulerConfig.memoryPolicy.retrieveCommand) {

scripts/agent/verify-run-artifacts.mjs

@@ -133,6 +133,14 @@ function getMatchingArtifacts(files, { expectedPrefix, session }) {
   return files.filter((file) => file.name.startsWith(expectedPrefix));
 }
 
+function findInvalidFilenameCharacters(files) {
+  // Windows-invalid filename characters: <>:"/\|?*
+  const invalidCharRe = /[<>:"/\\|?*]/;
+  return files
+    .filter((file) => invalidCharRe.test(file.name))
+    .map((file) => file.name);
+}
+
 async function hasValidArtifactStructure(files, artifact) {
   for (const file of files) {
     const content = await fs.readFile(file.filePath, 'utf8').catch(() => '');
@@ -336,6 +344,11 @@ async function main() {
       continue;
     }
 
+    const invalidFilenames = findInvalidFilenameCharacters(matchingArtifacts);
+    if (invalidFilenames.length) {
+      missing.push(`${artifact.dir}: invalid filename characters for cross-platform sync in ${invalidFilenames.join(', ')}`);
+    }
+
     const hasValidStructure = await hasValidArtifactStructure(matchingArtifacts, artifact);
     if (!hasValidStructure) {
       missing.push(`${artifact.dir}: ${artifact.structureHint}`);

src/prompts/scheduler-flow.md

@@ -26,6 +26,8 @@ Every agent prompt invoked by the schedulers (daily/weekly) MUST enforce this co
    - `docs/agent-handoffs/README.md`
    - Recent notes in `docs/agent-handoffs/learnings/` and `docs/agent-handoffs/incidents/`
 2. **Update run artifacts** in `src/context/`, `src/todo/`, `src/decisions/`, and `src/test_logs/` during the run, or explicitly document why each artifact update is not needed for that run.
+   - When creating filenames with `<timestamp>`, use the scheduler-provided `SCHEDULER_RUN_TIMESTAMP` value when available.
+   - Required filename-safe format: `YYYY-MM-DDTHH-MM-SSZ` (for example `2026-02-15T01-03-31Z`); never use `:` in filenames.
 3. **Capture reusable failures and unresolved issues**:
    - Record reusable failures in `docs/agent-handoffs/incidents/`
    - Record active unresolved reproducible items in `KNOWN_ISSUES.md`

test/verify-run-artifacts.test.mjs

@@ -102,3 +102,25 @@ test('fails when failure identifiers are not cross-linked to known issues or inc
   assert.equal(result.code, 1);
   assert.match(result.stderr, /not cross-linked/i);
 });
+
+test('fails when artifact filenames contain Windows-invalid characters', async () => {
+  const root = await setupFixture();
+  await writeArtifacts(root, { includeMetadata: true });
+  await fs.writeFile(path.join(root, 'KNOWN_ISSUES.md'), '_No active issues currently documented._\n', 'utf8');
+
+  const validPath = path.join(root, 'src', 'test_logs', 'TEST_LOG_1.md');
+  const invalidPath = path.join(root, 'src', 'test_logs', 'TEST_LOG_2026-02-15T01:03:31Z.md');
+  const content = await fs.readFile(validPath, 'utf8');
+  await fs.writeFile(invalidPath, content, 'utf8');
+  await fs.unlink(validPath);
+
+  const result = await runVerify(root, [
+    '--agent', 'docs-agent',
+    '--cadence', 'daily',
+    '--prompt-path', 'src/prompts/daily/docs-agent.md',
+  ]);
+
+  assert.equal(result.code, 1);
+  assert.match(result.stderr, /invalid filename characters/i);
+  assert.match(result.stderr, /TEST_LOG_2026-02-15T01:03:31Z\.md/);
+});