feat: integrate Jinja2 templating for agent responses and memory consolidation

- Added Jinja2 template support for various agent responses, including identity, skills, and memory consolidation.
- Introduced new templates for evaluating notifications, handling subagent announcements, and managing platform policies.
- Updated the agent context and memory modules to utilize the new templating system for improved readability and maintainability.
- Added a new dependency on Jinja2 in pyproject.toml.

nanobot/utils/evaluator.py

@@ -10,6 +10,8 @@ from typing import TYPE_CHECKING
 
 from loguru import logger
 
+from nanobot.utils.prompt_templates import render_template
+
 if TYPE_CHECKING:
     from nanobot.providers.base import LLMProvider
 
@@ -37,19 +39,6 @@ _EVALUATE_TOOL = [
     }
 ]
 
-_SYSTEM_PROMPT = (
-    "You are a notification gate for a background agent. "
-    "You will be given the original task and the agent's response. "
-    "Call the evaluate_notification tool to decide whether the user "
-    "should be notified.\n\n"
-    "Notify when the response contains actionable information, errors, "
-    "completed deliverables, or anything the user explicitly asked to "
-    "be reminded about.\n\n"
-    "Suppress when the response is a routine status check with nothing "
-    "new, a confirmation that everything is normal, or essentially empty."
-)
-
-
 async def evaluate_response(
     response: str,
     task_context: str,
@@ -65,10 +54,12 @@ async def evaluate_response(
     try:
         llm_response = await provider.chat_with_retry(
             messages=[
-                {"role": "system", "content": _SYSTEM_PROMPT},
-                {"role": "user", "content": (
-                    f"## Original task\n{task_context}\n\n"
-                    f"## Agent response\n{response}"
+                {"role": "system", "content": render_template("agent/evaluator.md", part="system")},
+                {"role": "user", "content": render_template(
+                    "agent/evaluator.md",
+                    part="user",
+                    task_context=task_context,
+                    response=response,
                 )},
             ],
             tools=_EVALUATE_TOOL,

nanobot/utils/prompt_templates.py

@@ -0,0 +1,35 @@
+"""Load and render agent system prompt templates (Jinja2) under nanobot/templates/.
+
+Agent prompts live in ``templates/agent/`` (pass names like ``agent/identity.md``).
+Shared copy lives under ``agent/_snippets/`` and is included via
+``{% include 'agent/_snippets/....md' %}``.
+"""
+
+from functools import lru_cache
+from pathlib import Path
+from typing import Any
+
+from jinja2 import Environment, FileSystemLoader
+
+_TEMPLATES_ROOT = Path(__file__).resolve().parent.parent / "templates"
+
+
+@lru_cache
+def _environment() -> Environment:
+    # Plain-text prompts: do not HTML-escape variable values.
+    return Environment(
+        loader=FileSystemLoader(str(_TEMPLATES_ROOT)),
+        autoescape=False,
+        trim_blocks=True,
+        lstrip_blocks=True,
+    )
+
+
+def render_template(name: str, *, strip: bool = False, **kwargs: Any) -> str:
+    """Render ``name`` (e.g. ``agent/identity.md``, ``agent/platform_policy.md``) under ``templates/``.
+
+    Use ``strip=True`` for single-line user-facing strings when the file ends
+    with a trailing newline you do not want preserved.
+    """
+    text = _environment().get_template(name).render(**kwargs)
+    return text.rstrip() if strip else text