feat: improve generated agent prompts

tests/test_prompt.py

@@ -2,7 +2,25 @@ from pathlib import Path
 
 import pytest
 
-from rdb_discovery.tasks import generate_agent_prompt, get_next_task
+from rdb_discovery.tasks import (
+    _extract_test_commands_from_claude,
+    generate_agent_prompt,
+    get_next_task,
+)
+
+
+def _write_claude_with_test_cmds(tmp_path: Path) -> None:
+    """Write a CLAUDE.md with Test Commands section."""
+    (tmp_path / "CLAUDE.md").write_text(
+        "# Claude Code Instructions\n\n"
+        "## Test Commands\n\n"
+        "Use the existing virtual environment.\n\n"
+        "```bash\n"
+        "source .venv/bin/activate\n"
+        "python -m pytest\n"
+        "```\n",
+        encoding="utf-8",
+    )
 
 
 def test_generate_agent_prompt_includes_task_info(tmp_path: Path) -> None:
@@ -67,7 +85,7 @@ def test_generate_agent_prompt_includes_read_instructions(tmp_path: Path) -> Non
     assert "context/agent-guidelines.md" in prompt
 
 
-def test_generate_agent_prompt_includes_one_task_constraint(tmp_path: Path) -> None:
+def test_generate_agent_prompt_includes_one_step_constraint(tmp_path: Path) -> None:
     (tmp_path / "TASKS.md").write_text(
         "# TASKS\n\n"
         "## TASK-001 — First\nStatus: Done\n\n"
@@ -79,7 +97,7 @@ def test_generate_agent_prompt_includes_one_task_constraint(tmp_path: Path) -> N
 
     prompt = generate_agent_prompt(tmp_path)
 
-    assert "ONE task only" in prompt or "one task only" in prompt
+    assert "ONE small implementation step only" in prompt
 
 
 def test_generate_agent_prompt_includes_validation(tmp_path: Path) -> None:
@@ -129,3 +147,115 @@ def test_generate_agent_prompt_no_tasks_file(tmp_path: Path) -> None:
     prompt = generate_agent_prompt(tmp_path)
 
     assert prompt == "No Todo task found."
+
+
+def test_generate_agent_prompt_includes_implementation_gap(tmp_path: Path) -> None:
+    (tmp_path / "TASKS.md").write_text(
+        "# TASKS\n\n"
+        "## TASK-001 — First\nStatus: Done\n\n"
+        "Goal: x.\n\n"
+        "## TASK-002 — Second\nStatus: Todo\n\n"
+        "Goal: y.\n"
+        "Implementation Gap:\n"
+        "Missing validation handler in cli.py\n",
+        encoding="utf-8",
+    )
+
+    prompt = generate_agent_prompt(tmp_path)
+
+    assert "Implementation Gap:" in prompt
+    assert "Missing validation handler in cli.py" in prompt
+
+
+def test_generate_agent_prompt_omits_gap_when_missing(tmp_path: Path) -> None:
+    (tmp_path / "TASKS.md").write_text(
+        "# TASKS\n\n"
+        "## TASK-001 — First\nStatus: Done\n\n"
+        "Goal: x.\n\n"
+        "## TASK-002 — Second\nStatus: Todo\n\n"
+        "Goal: y.\n",
+        encoding="utf-8",
+    )
+
+    prompt = generate_agent_prompt(tmp_path)
+
+    assert "Implementation Gap:" not in prompt
+
+
+def test_generate_agent_prompt_includes_test_commands_from_claude(tmp_path: Path) -> None:
+    (tmp_path / "TASKS.md").write_text(
+        "# TASKS\n\n"
+        "## TASK-001 — First\nStatus: Done\n\n"
+        "## TASK-002 — Second\nStatus: Todo\n\n"
+        "Goal: y.\n",
+        encoding="utf-8",
+    )
+    _write_claude_with_test_cmds(tmp_path)
+
+    prompt = generate_agent_prompt(tmp_path)
+
+    assert "Test Commands (from CLAUDE.md)" in prompt
+    assert "source .venv/bin/activate" in prompt
+    assert "python -m pytest" in prompt
+
+
+def test_generate_agent_prompt_includes_no_reread_constraint(tmp_path: Path) -> None:
+    (tmp_path / "TASKS.md").write_text(
+        "# TASKS\n\n"
+        "## TASK-001 — First\nStatus: Done\n\n"
+        "## TASK-002 — Second\nStatus: Todo\n\n"
+        "Goal: y.\n",
+        encoding="utf-8",
+    )
+
+    prompt = generate_agent_prompt(tmp_path)
+
+    assert "reread" in prompt.lower() or "read" in prompt.lower()
+
+
+def test_generate_agent_prompt_includes_inspect_first_constraint(tmp_path: Path) -> None:
+    (tmp_path / "TASKS.md").write_text(
+        "# TASKS\n\n"
+        "## TASK-001 — First\nStatus: Done\n\n"
+        "## TASK-002 — Second\nStatus: Todo\n\n"
+        "Goal: y.\n",
+        encoding="utf-8",
+    )
+
+    prompt = generate_agent_prompt(tmp_path)
+
+    assert "Inspect" in prompt or "inspect" in prompt
+
+
+def test_extract_test_commands_no_claude_file(tmp_path: Path) -> None:
+    commands = _extract_test_commands_from_claude(tmp_path)
+    assert commands == []
+
+
+def test_extract_test_commands_from_claude(tmp_path: Path) -> None:
+    (tmp_path / "CLAUDE.md").write_text(
+        "# Instructions\n\n"
+        "## Test Commands\n\n"
+        "Run the following:\n\n"
+        "```bash\n"
+        "source .venv/bin/activate\n"
+        "python -m pytest\n"
+        "```\n",
+        encoding="utf-8",
+    )
+
+    commands = _extract_test_commands_from_claude(tmp_path)
+
+    assert any(".venv/bin/activate" in cmd for cmd in commands)
+    assert "python -m pytest" in commands
+
+
+def test_extract_test_commands_no_section(tmp_path: Path) -> None:
+    (tmp_path / "CLAUDE.md").write_text(
+        "# Instructions\n\n"
+        "No test section here.\n",
+        encoding="utf-8",
+    )
+
+    commands = _extract_test_commands_from_claude(tmp_path)
+    assert commands == []