fix(review): harden cron security, session lifecycle, skip policy (PR #141)

- Reject multi-line prompts end-to-end: schema refines on promptText/
  launchCommand, runtime check in resolvePrompt (prompt-file content;
  trailing newlines tolerated), matching cron-ui form validation — delivery
  is single-line only, so multi-line was silently corrupted (typed mode
  fused lines, paste mode submitted partials)
- Close the workingDir confinement bypass (arbitrary server-side file read,
  e.g. workingDir=/proc + /proc/self/environ): realpath-resolve workingDir
  before the containment check, reject '/' and blocked/pseudo-fs trees
  (/proc, /sys, /dev + the attachment-guard blocklist) at fire time AND at
  job create/update (workingDir must exist and be a directory)
- Session lifecycle: new per-job autoClosePreviousSession (default true,
  recurring schedules only; ignored for 'once') — the previous run's
  still-open session is closed via the normal cleanupSession path when the
  next run fires; UI switch added; 50-session cap math documented in
  docs/cron-guide.md §8
- skip_if_same_agent_running: count only live sessions (exclude
  stopped/error dead tabs), exclude sessions created by this job's own runs
  (fixes the fire-once-then-skip-forever self-deadlock), and a skipped
  'once' job stays armed and retries next tick instead of being consumed;
  liveness filter mirrored in cron-ui _countActiveAgents
- Wire launchCommand (was accepted+documented but dead): shell mode sends
  it via writeViaMux as the first input line after startShell readiness
  (single-line, schema-enforced); form field shown for shell agent type
- Record delivery failures: a false writeViaMux result now fails the run
  instead of recording a false 'prompt_sent'
- Cap saved jobs at MAX_CRON_JOBS (100) to bound state.json growth
- Surface field-specific schema messages (drop parseBody custom
  errorMessage on cron create/update)
- Tests: workingDir create/update validation, /proc bypass regression,
  single-line enforcement (schema+runtime+trailing-newline tolerance),
  live/own-session skip filtering, once-skip re-arm, auto-close on/off/once,
  job-count cap

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/web/public/cron-ui.js

@@ -126,6 +126,7 @@ Object.assign(CodemanApp.prototype, {
     document.getElementById('schName').value = job ? job.name || '' : '';
     document.getElementById('schAgentType').value = job ? job.agentType || 'claude' : 'claude';
     document.getElementById('schWorkingDir').value = job ? job.workingDir || '' : '';
+    document.getElementById('schLaunchCommand').value = job ? job.launchCommand || '' : '';
     document.getElementById('schPromptMode').value = job ? job.promptMode || 'inline_text' : 'inline_text';
     document.getElementById('schPromptText').value = job ? job.promptText || '' : '';
     document.getElementById('schPromptFilePath').value = job ? job.promptFilePath || '' : '';
@@ -140,9 +141,11 @@ Object.assign(CodemanApp.prototype, {
       cb.checked = weekly.includes(Number(cb.value));
     });
     document.getElementById('schConcurrencyPolicy').value = job ? job.concurrencyPolicy || 'warn_only' : 'warn_only';
+    document.getElementById('schAutoClosePrev').checked = job ? job.autoClosePreviousSession !== false : true;
     document.getElementById('schEnabled').checked = job ? !!job.enabled : true;
     document.getElementById('schNotes').value = job ? job.notes || '' : '';
 
+    this.onCronAgentTypeChange();
     this.onCronPromptModeChange();
     this.onCronScheduleTypeChange();
     form.classList.remove('hidden');
@@ -158,6 +161,12 @@ Object.assign(CodemanApp.prototype, {
     if (form) form.classList.add('hidden');
   },
 
+  onCronAgentTypeChange() {
+    // Launch command is only meaningful for shell mode (first input line).
+    const isShell = document.getElementById('schAgentType').value === 'shell';
+    document.getElementById('schLaunchCommandRow').classList.toggle('hidden', !isShell);
+  },
+
   onCronPromptModeChange() {
     const mode = document.getElementById('schPromptMode').value;
     document.getElementById('schPromptTextRow').classList.toggle('hidden', mode !== 'inline_text');
@@ -191,11 +200,18 @@ Object.assign(CodemanApp.prototype, {
       inputMode: document.getElementById('schInputMode').value,
       scheduleType: t,
       concurrencyPolicy: document.getElementById('schConcurrencyPolicy').value,
+      autoClosePreviousSession: document.getElementById('schAutoClosePrev').checked,
       enabled: document.getElementById('schEnabled').checked,
       notes: document.getElementById('schNotes').value.trim() || undefined,
     };
-    if (promptMode === 'inline_text') body.promptText = document.getElementById('schPromptText').value;
-    else body.promptFilePath = document.getElementById('schPromptFilePath').value.trim();
+    // Always sent for shell (an emptied field must clear a saved command on edit).
+    if (body.agentType === 'shell') body.launchCommand = document.getElementById('schLaunchCommand').value.trim();
+    if (promptMode === 'inline_text') {
+      // Prompt delivery is single-line only; trailing newlines are harmless, strip them.
+      body.promptText = document.getElementById('schPromptText').value.replace(/[\r\n]+$/, '');
+    } else {
+      body.promptFilePath = document.getElementById('schPromptFilePath').value.trim();
+    }
 
     if (t === 'once') {
       const v = document.getElementById('schRunAt').value;
@@ -225,6 +241,10 @@ Object.assign(CodemanApp.prototype, {
       errEl.textContent = 'Working directory is required.';
       return;
     }
+    if (body.promptText !== undefined && /[\r\n]/.test(body.promptText)) {
+      errEl.textContent = 'Prompt must be a single line — multi-line prompts are not supported.';
+      return;
+    }
     const id = document.getElementById('schJobId').value;
     const res = id ? await this._apiPut(`/api/cron/jobs/${id}`, body) : await this._apiPost('/api/cron/jobs', body);
     if (!res || !res.ok) {
@@ -279,9 +299,13 @@ Object.assign(CodemanApp.prototype, {
   },
 
   _countActiveAgents(agentType) {
+    // Mirrors the server's countActiveAgents: only LIVE sessions count — a
+    // tab whose CLI already exited (stopped/error) doesn't block anything.
     if (!this.sessions) return 0;
     let n = 0;
-    for (const s of this.sessions.values()) if (s && s.mode === agentType) n++;
+    for (const s of this.sessions.values()) {
+      if (s && s.mode === agentType && s.status !== 'stopped' && s.status !== 'error') n++;
+    }
     return n;
   },
 

src/web/public/index.html

@@ -594,7 +594,7 @@
             <input type="hidden" id="schJobId">
             <div class="form-row"><label>Name</label><input type="text" id="schName" placeholder="My nightly job"></div>
             <div class="form-row"><label>Agent Type</label>
-              <select id="schAgentType">
+              <select id="schAgentType" onchange="app.onCronAgentTypeChange()">
                 <option value="claude">Claude</option>
                 <option value="shell">Terminal / Shell</option>
                 <option value="opencode">OpenCode</option>
@@ -603,6 +603,7 @@
               </select>
             </div>
             <div class="form-row"><label>Working Directory</label><input type="text" id="schWorkingDir" placeholder="/absolute/path"></div>
+            <div class="form-row hidden" id="schLaunchCommandRow"><label>Launch Command</label><input type="text" id="schLaunchCommand" placeholder="Optional — runs as the first command in the new shell"></div>
             <div class="form-row"><label>Prompt Source</label>
               <select id="schPromptMode" onchange="app.onCronPromptModeChange()">
                 <option value="inline_text">Inline text</option>
@@ -646,6 +647,9 @@
                 <option value="skip_if_same_agent_running">Skip this run</option>
               </select>
             </div>
+            <div class="form-row form-row-switch"><label title="Recurring schedules only: when the next run fires, the still-open session created by this job's previous run is closed first">Auto-close previous run's session</label>
+              <label class="switch"><input type="checkbox" id="schAutoClosePrev" checked><span class="slider"></span></label>
+            </div>
             <div class="form-row form-row-switch"><label>Enabled</label>
               <label class="switch"><input type="checkbox" id="schEnabled" checked><span class="slider"></span></label>
             </div>

src/web/routes/cron-routes.ts

@@ -20,7 +20,9 @@ export function registerCronRoutes(app: FastifyInstance, ctx: CronPort): void {
   });
 
   app.post('/api/cron/jobs', async (req) => {
-    const body = parseBody(CronJobSchema, req.body, 'Invalid cron job');
+    // No custom errorMessage: surface the schema's field-specific messages
+    // (e.g. "runAt is required for a one-time schedule").
+    const body = parseBody(CronJobSchema, req.body);
     return { job: ctx.cron.createJob(body) };
   });
 
@@ -33,7 +35,7 @@ export function registerCronRoutes(app: FastifyInstance, ctx: CronPort): void {
 
   app.put('/api/cron/jobs/:id', async (req) => {
     const { id } = req.params as { id: string };
-    const body = parseBody(CronJobUpdateSchema, req.body, 'Invalid cron job update');
+    const body = parseBody(CronJobUpdateSchema, req.body);
     const job = ctx.cron.updateJob(id, body);
     if (!job) return createErrorResponse(ApiErrorCode.NOT_FOUND, 'Cron job not found');
     return { job };
@@ -62,7 +64,7 @@ export function registerCronRoutes(app: FastifyInstance, ctx: CronPort): void {
     const job = ctx.cron.getJob(id);
     if (!job) return createErrorResponse(ApiErrorCode.NOT_FOUND, 'Cron job not found');
     const run = await ctx.cron.runNow(id);
-    return { run, activeAgents: ctx.cron.countActiveAgents(job.agentType) };
+    return { run, activeAgents: ctx.cron.countActiveAgents(job.agentType, job.id) };
   });
 
   // ── Run history ──────────────────────────────────────────────────────────

src/web/schemas.ts

@@ -579,14 +579,21 @@ export const ScheduledRunSchema = z.object({
 /** 'HH:MM' 24-hour time. */
 const hhmmSchema = z.string().regex(/^([01]?\d|2[0-3]):[0-5]\d$/, 'Time must be HH:MM (24-hour)');
 
+/** Prompt delivery is single-line only (writeViaMux/Ink constraint) — reject newlines outright. */
+const noNewlines = (v: string) => !/[\r\n]/.test(v);
+
 /** Shared field shape for creating/updating a scheduled job. */
 const CronJobBaseSchema = z.object({
   name: z.string().min(1).max(200),
   agentType: z.enum(['claude', 'shell', 'opencode', 'codex', 'gemini']),
   workingDir: safePathSchema,
-  launchCommand: z.string().max(2000).optional(),
+  launchCommand: z.string().max(2000).refine(noNewlines, 'launchCommand must be a single line').optional(),
   promptMode: z.enum(['inline_text', 'prompt_file_path']),
-  promptText: z.string().max(100000).optional(),
+  promptText: z
+    .string()
+    .max(100000)
+    .refine(noNewlines, 'promptText must be a single line (multi-line prompts are not supported)')
+    .optional(),
   promptFilePath: safePathSchema.optional(),
   inputMode: z.enum(['paste', 'typed']),
   scheduleType: z.enum(['once', 'interval', 'daily', 'weekly']),
@@ -598,6 +605,7 @@ const CronJobBaseSchema = z.object({
   enabled: z.boolean(),
   notes: z.string().max(2000).optional(),
   concurrencyPolicy: z.enum(['warn_only', 'skip_if_same_agent_running']),
+  autoClosePreviousSession: z.boolean().optional(),
 });
 
 /** Cross-field validation: required fields depend on promptMode + scheduleType. */