diff --git a/conductor/workflow.md b/conductor/workflow.md
index 7eec3fe..745bdf9 100644
--- a/conductor/workflow.md
+++ b/conductor/workflow.md
@@ -36,6 +36,7 @@ All tasks follow a strict lifecycle:
    - **Minimize Token Burn:** Only use `read_file` with `start_line`/`end_line` for specific implementation details once target areas are identified.
 4. **Write Failing Tests (Red Phase):**
    - **Pre-Delegation Checkpoint:** Before spawning a worker for dangerous or non-trivial changes, ensure your current progress is staged (`git add .`) or committed. This prevents losing iterations if a sub-agent incorrectly uses `git restore`.
+   - **Zero-Assertion Ban:** You MUST NOT write tests that contain only `pass` or lack meaningful assertions. A test is only valid if it contains assertions that explicitly test the behavioral change and verify the failure condition.
    - **Code Style:** ALWAYS explicitly mention "Use exactly 1-space indentation for Python code" when prompting a sub-agent.
    - **Delegate Test Creation:** Do NOT write test code directly. Spawn a Tier 3 Worker (`python scripts/mma_exec.py --role tier3-worker "[PROMPT]"`) with a **surgical prompt** specifying WHERE (file:line range), WHAT (test to create), HOW (which assertions/fixtures to use), and SAFETY (thread constraints if applicable). Example: `"Write tests in tests/test_cost_tracker.py for cost_tracker.py:estimate_cost(). Test all model patterns in MODEL_PRICING dict. Assert unknown model returns 0. Use 1-space indentation."` (If repeating due to failures, pass `--failure-count X` to switch to a more capable model).
    - Take the code generated by the Worker and apply it.