Generation Test Attempt 6: EXECUTE Phase Hangs — 0 Modules After 15+ Minutes

Session 138.4 | February 23, 2026 | Testing Director

Executive Summary

The coding agent applied the name-matching fix to execute.phase.ts (case/format-insensitive matching via normalizeForMatch()). This fix changed EXECUTE behavior significantly:

• Attempt 5 (before fix): EXECUTE completed in ~30 seconds, generated 1 module (only 1 name match due to strict equality)
• Attempt 6 (after fix): EXECUTE hung for 15+ minutes, generated 0 modules, timer froze at 14:36

The fix is correct in principle (matching more modules) but exposed a new problem: the EXECUTE phase makes sequential LLM calls for each matched module, and these calls appear to hang or timeout silently without delivering results.

Test Results Summary

What Happened Step by Step

1. 1:54:27 PM — Generation started (Fitness Studio template)
2. ~1:54:30 — ENHANCE phase ✅ completed
3. ~1:55:00 — ANALYZE phase ✅ completed (maxTokens fix working)
4. ~1:55:30 — DECOMPOSE phase ✅ completed
5. ~1:56:00 — PLAN phase ✅ completed
6. ~1:56:30 — EXECUTE phase started ("Module Generation")
7. ... 15+ minutes pass ...
8. 2:10+ PM — Still at 80%, "Module Generation", 0 files, 0 modules, timer frozen at 14:36
9. SSE connection: Still shows LIVE badge but timer frozen
10. Console: No errors, no warnings, no module-related messages
11. Network: SSE connection still HTTP 200 but no new events received

Root Cause Analysis

The Fix Applied (Correct)

File: execute.phase.ts line 70-74

const normalizeForMatch = (s: string) => s.toLowerCase().replace(/[\s\-_]+/g, '');

for (const plan of executionPlan) {
  const planKey = normalizeForMatch(plan.moduleName);
  const moduleSpec = decomposeResult.modules.find(m => normalizeForMatch(m.name) === planKey);

This fix is correct — it properly handles the case/format mismatch between PLAN (kebab-case) and DECOMPOSE (title-case) module names.

Why It Now Hangs

Before the fix: Only ~1 module matched → 1 LLM call → completed quickly After the fix: ~5-6 modules match → 5-6 sequential LLM calls → hangs

The issue is in generateVisual() (line 180-233):

const response = await provider.sendMessage(
  [{ role: 'user', content: `Generate ModuleContext JSON for the ${plan.moduleName} module.` }],
  [],
  sendOptions,
);

Possible causes for the hang:

1. No LLM timeout configured: SendOptions has maxTokens: 8192 and temperature: 0.2 but no timeout. If the LLM provider is slow or rate-limited, the call hangs indefinitely.

2. LLM provider rate limiting: With 5-6 rapid sequential calls (each requesting 8192 tokens), the LLM provider may rate-limit after the first 1-2 calls. Without a timeout, the code waits forever.

3. Provider connection pool exhaustion: Sequential calls through the same provider factory may exhaust connection limits.

4. Silent failure in sendMessage: The LLM call may throw an error that's caught by generateVisual()'s try/catch, which returns { module: null }. But if the error occurs DURING the await (e.g., a hanging promise), it never resolves.

Fix Recommendations

Priority 1: Add LLM Call Timeout (CRITICAL)

In execute.phase.ts generateVisual() and generateCode(), wrap the LLM call with a timeout:

// Option A: Add timeout to SendOptions if the provider supports it
const sendOptions: SendOptions = {
  systemPrompt,
  maxTokens: 8192,
  temperature: 0.2,
  timeout: 120_000, // 2 minutes per module
};

// Option B: Wrap with Promise.race if provider doesn't support timeout
const timeoutPromise = new Promise((_, reject) =>
  setTimeout(() => reject(new Error('LLM call timeout after 120s')), 120_000)
);
const response = await Promise.race([
  provider.sendMessage(messages, [], sendOptions),
  timeoutPromise,
]) as LLMResponse;

Priority 2: Add Per-Module Progress SSE Events

The EXECUTE phase should emit SSE events for each module attempt, so the frontend can show progress:

for (const plan of executionPlan) {
  sseSubject?.next({
    type: 'module-gen.phase-progress',
    sessionId: '',
    data: {
      phase: 'EXECUTE',
      step: 'generating',
      message: `Generating module: ${plan.moduleName} (${index + 1}/${executionPlan.length})`,
      progress: Math.round((index / executionPlan.length) * 100),
    },
    timestamp: new Date().toISOString(),
  });

  // ... generate module ...
}

Priority 3: Add Retry with Backoff

If an LLM call fails or times out, retry once with a short backoff:

const maxRetries = 1;
for (let attempt = 0; attempt <= maxRetries; attempt++) {
  try {
    const response = await this.generateVisualWithTimeout(plan, moduleSpec, entities, 120_000);
    if (response.module) allModules.push(response.module);
    break;
  } catch (err) {
    if (attempt < maxRetries) {
      this.logger.warn(`Retrying ${plan.moduleName} after ${err.message}`);
      await new Promise(r => setTimeout(r, 2000));
    }
  }
}

Priority 4: Check Provider Rate Limits

Verify the LLM provider configuration in ProviderFactoryService.getDefault():

• What provider is being used? (OpenAI, Anthropic, local?)
• What are the rate limits?
• Is there a request queue?

Files to Modify

Evidence

Console (No module messages)

[1:54:27 PM] 🚀 [VibeGenerator] Starting generation now...
... (no module-related messages for 15+ minutes)

Frontend Status Bar

0 files | 0 modules | ⏱ 14:36 (frozen)

SSE Connection

• Status: HTTP 200 (still technically open)
• LIVE badge: Displayed but no new events arriving
• Last event received: module-gen.phase-start for EXECUTE phase

Progress Tracker: All Bugs

Recommended Testing After Fix

1. Add 120-second timeout to LLM calls in generateVisual() and generateCode()
2. Add per-module SSE progress events
3. Re-run Fitness Studio generation
4. Observe: modules should generate in ~2-3 minutes total (6 modules × ~20-30 sec each with timeout protection)
5. Verify module count > 1 in the success screen
6. Test "Deploy to Universe"
7. Verify Hub shows modules