nanobot/nanobot/agent/skills.py
2026-02-01 18:45:42 +00:00

229 lines
8.3 KiB
Python

"""Skills loader for agent capabilities."""
import json
import os
import re
import shutil
from pathlib import Path
# Default builtin skills directory (relative to this file)
BUILTIN_SKILLS_DIR = Path(__file__).parent.parent / "skills"
class SkillsLoader:
"""
Loader for agent skills.
Skills are markdown files (SKILL.md) that teach the agent how to use
specific tools or perform certain tasks.
"""
def __init__(self, workspace: Path, builtin_skills_dir: Path | None = None):
self.workspace = workspace
self.workspace_skills = workspace / "skills"
self.builtin_skills = builtin_skills_dir or BUILTIN_SKILLS_DIR
def list_skills(self, filter_unavailable: bool = True) -> list[dict[str, str]]:
"""
List all available skills.
Args:
filter_unavailable: If True, filter out skills with unmet requirements.
Returns:
List of skill info dicts with 'name', 'path', 'source'.
"""
skills = []
# Workspace skills (highest priority)
if self.workspace_skills.exists():
for skill_dir in self.workspace_skills.iterdir():
if skill_dir.is_dir():
skill_file = skill_dir / "SKILL.md"
if skill_file.exists():
skills.append({"name": skill_dir.name, "path": str(skill_file), "source": "workspace"})
# Built-in skills
if self.builtin_skills and self.builtin_skills.exists():
for skill_dir in self.builtin_skills.iterdir():
if skill_dir.is_dir():
skill_file = skill_dir / "SKILL.md"
if skill_file.exists() and not any(s["name"] == skill_dir.name for s in skills):
skills.append({"name": skill_dir.name, "path": str(skill_file), "source": "builtin"})
# Filter by requirements
if filter_unavailable:
return [s for s in skills if self._check_requirements(self._get_skill_meta(s["name"]))]
return skills
def load_skill(self, name: str) -> str | None:
"""
Load a skill by name.
Args:
name: Skill name (directory name).
Returns:
Skill content or None if not found.
"""
# Check workspace first
workspace_skill = self.workspace_skills / name / "SKILL.md"
if workspace_skill.exists():
return workspace_skill.read_text(encoding="utf-8")
# Check built-in
if self.builtin_skills:
builtin_skill = self.builtin_skills / name / "SKILL.md"
if builtin_skill.exists():
return builtin_skill.read_text(encoding="utf-8")
return None
def load_skills_for_context(self, skill_names: list[str]) -> str:
"""
Load specific skills for inclusion in agent context.
Args:
skill_names: List of skill names to load.
Returns:
Formatted skills content.
"""
parts = []
for name in skill_names:
content = self.load_skill(name)
if content:
content = self._strip_frontmatter(content)
parts.append(f"### Skill: {name}\n\n{content}")
return "\n\n---\n\n".join(parts) if parts else ""
def build_skills_summary(self) -> str:
"""
Build a summary of all skills (name, description, path, availability).
This is used for progressive loading - the agent can read the full
skill content using read_file when needed.
Returns:
XML-formatted skills summary.
"""
all_skills = self.list_skills(filter_unavailable=False)
if not all_skills:
return ""
def escape_xml(s: str) -> str:
return s.replace("&", "&amp;").replace("<", "&lt;").replace(">", "&gt;")
lines = ["<skills>"]
for s in all_skills:
name = escape_xml(s["name"])
path = s["path"]
desc = escape_xml(self._get_skill_description(s["name"]))
skill_meta = self._get_skill_meta(s["name"])
available = self._check_requirements(skill_meta)
lines.append(f" <skill available=\"{str(available).lower()}\">")
lines.append(f" <name>{name}</name>")
lines.append(f" <description>{desc}</description>")
lines.append(f" <location>{path}</location>")
# Show missing requirements for unavailable skills
if not available:
missing = self._get_missing_requirements(skill_meta)
if missing:
lines.append(f" <requires>{escape_xml(missing)}</requires>")
lines.append(f" </skill>")
lines.append("</skills>")
return "\n".join(lines)
def _get_missing_requirements(self, skill_meta: dict) -> str:
"""Get a description of missing requirements."""
missing = []
requires = skill_meta.get("requires", {})
for b in requires.get("bins", []):
if not shutil.which(b):
missing.append(f"CLI: {b}")
for env in requires.get("env", []):
if not os.environ.get(env):
missing.append(f"ENV: {env}")
return ", ".join(missing)
def _get_skill_description(self, name: str) -> str:
"""Get the description of a skill from its frontmatter."""
meta = self.get_skill_metadata(name)
if meta and meta.get("description"):
return meta["description"]
return name # Fallback to skill name
def _strip_frontmatter(self, content: str) -> str:
"""Remove YAML frontmatter from markdown content."""
if content.startswith("---"):
match = re.match(r"^---\n.*?\n---\n", content, re.DOTALL)
if match:
return content[match.end():].strip()
return content
def _parse_nanobot_metadata(self, raw: str) -> dict:
"""Parse nanobot metadata JSON from frontmatter."""
try:
data = json.loads(raw)
return data.get("nanobot", {}) if isinstance(data, dict) else {}
except (json.JSONDecodeError, TypeError):
return {}
def _check_requirements(self, skill_meta: dict) -> bool:
"""Check if skill requirements are met (bins, env vars)."""
requires = skill_meta.get("requires", {})
for b in requires.get("bins", []):
if not shutil.which(b):
return False
for env in requires.get("env", []):
if not os.environ.get(env):
return False
return True
def _get_skill_meta(self, name: str) -> dict:
"""Get nanobot metadata for a skill (cached in frontmatter)."""
meta = self.get_skill_metadata(name) or {}
return self._parse_nanobot_metadata(meta.get("metadata", ""))
def get_always_skills(self) -> list[str]:
"""Get skills marked as always=true that meet requirements."""
result = []
for s in self.list_skills(filter_unavailable=True):
meta = self.get_skill_metadata(s["name"]) or {}
skill_meta = self._parse_nanobot_metadata(meta.get("metadata", ""))
if skill_meta.get("always") or meta.get("always"):
result.append(s["name"])
return result
def get_skill_metadata(self, name: str) -> dict | None:
"""
Get metadata from a skill's frontmatter.
Args:
name: Skill name.
Returns:
Metadata dict or None.
"""
content = self.load_skill(name)
if not content:
return None
if content.startswith("---"):
match = re.match(r"^---\n(.*?)\n---", content, re.DOTALL)
if match:
# Simple YAML parsing
metadata = {}
for line in match.group(1).split("\n"):
if ":" in line:
key, value = line.split(":", 1)
metadata[key.strip()] = value.strip().strip('"\'')
return metadata
return None