feat: support role-based agent prompts

src/rdb_discovery/tasks.py

@@ -7,12 +7,21 @@ import re
 TASK_HEADING_RE = re.compile(r"^##\s+(TASK-\d+)\s+[-–—]\s+(.+)$", re.MULTILINE)
 STATUS_RE = re.compile(r"^Status:\s*(.+)$", re.MULTILINE)
 
-
 GOAL_RE = re.compile(r"^Goal:\s*(.+)", re.MULTILINE)
 AC_RE = re.compile(r"^- (.+)$", re.MULTILINE)
 GAP_RE = re.compile(r"^Implementation Gap:\s*(.+)", re.MULTILINE)
 
 
+def _indefinite_article(word: str) -> str:
+    """Return 'a' or 'an' based on the first letter of word."""
+    if not word:
+        return "an"
+    first = word[0].lower()
+    if first in "aeiou":
+        return "an"
+    return "a"
+
+
 @dataclass
 class Task:
     task_id: str
@@ -20,6 +29,15 @@ class Task:
     status: str
     body: str
 
+    def role(self, root: Path) -> tuple[str, str]:
+        if "Role:" not in self.body:
+            return ("Implementation Agent", _indefinite_article("Implementation Agent"))
+        parts = self.body.split("Role:", 1)
+        value = parts[1].splitlines()[0].strip()
+        if value:
+            return (value, _indefinite_article(value))
+        return ("Implementation Agent", _indefinite_article("Implementation Agent"))
+
     def goal(self, root: Path) -> str:
         match = GOAL_RE.search(self.body)
         if match:
@@ -167,8 +185,10 @@ def generate_agent_prompt(root: Path) -> str:
     if not task:
         return "No Todo task found."
 
+    role_text, article = task.role(root)
+
     sections = [
-        "You are an implementation agent.",
+        f"You are {article} {role_text.lower()}.",
         "",
         "---",
         "",