learn-claude-code/s07_skill_loading/code.py
2026-08-15 00:03:45 +08:00

378 lines
12 KiB
Python

#!/usr/bin/env python3
"""
s07_skill_loading.py - Skill Loading
The system prompt contains a catalog of skill names and descriptions.
The model loads the full SKILL.md only when it calls load_skill.
skills/ Startup
+------------------+ +------------------+
| code-review/ | ----> | SkillLoader |
| SKILL.md | | name + summary |
| pdf/ | +--------+---------+
| SKILL.md | |
+------------------+ v
system prompt catalog
LLM -- load_skill(name) --> full SKILL.md
^ |
+--------- tool_result --------+
"""
import os
import subprocess
from pathlib import Path
import yaml
try:
import readline
readline.parse_and_bind('set bind-tty-special-chars off')
readline.parse_and_bind('set input-meta on')
readline.parse_and_bind('set output-meta on')
readline.parse_and_bind('set convert-meta off')
except ImportError:
pass
from anthropic import Anthropic
from dotenv import load_dotenv
load_dotenv(override=True)
if os.getenv("ANTHROPIC_BASE_URL"):
os.environ.pop("ANTHROPIC_AUTH_TOKEN", None)
WORKDIR = Path.cwd()
SKILLS_DIR = WORKDIR / "skills"
client = Anthropic(base_url=os.getenv("ANTHROPIC_BASE_URL"))
MODEL = os.environ["MODEL_ID"]
# -- Skill catalog --
class SkillLoader:
def __init__(self, skills_dir: Path):
self.skills_dir = skills_dir
self.skills: dict[str, dict[str, str]] = {}
self.scan()
@staticmethod
def parse_frontmatter(text: str) -> tuple[dict, str]:
lines = text.splitlines(keepends=True)
if not lines or lines[0].rstrip("\r\n") != "---":
return {}, text
closing_index = next(
(index for index, line in enumerate(lines[1:], start=1)
if line.rstrip("\r\n") == "---"),
None,
)
if closing_index is None:
return {}, text
frontmatter = "".join(lines[1:closing_index])
body = "".join(lines[closing_index + 1:]).strip()
try:
metadata = yaml.safe_load(frontmatter) or {}
except yaml.YAMLError:
metadata = {}
if not isinstance(metadata, dict):
metadata = {}
return metadata, body
def scan(self):
self.skills.clear()
if not self.skills_dir.exists():
return
skills_root = self.skills_dir.resolve()
for manifest in sorted(self.skills_dir.glob("*/SKILL.md")):
if (not manifest.is_file()
or not manifest.resolve().is_relative_to(skills_root)):
continue
content = manifest.read_text()
metadata, body = self.parse_frontmatter(content)
raw_name = metadata.get("name")
name = raw_name.strip() if isinstance(raw_name, str) else ""
name = name or manifest.parent.name
raw_description = metadata.get("description")
description = (raw_description.strip()
if isinstance(raw_description, str) else "")
description = description or body.split("\n", 1)[0]
description = " ".join(str(description).lstrip("# ").split())
self.skills[name] = {
"name": name,
"description": description,
"content": content,
}
def catalog(self) -> str:
if not self.skills:
return "(no skills found)"
return "\n".join(
f"- {skill['name']}: {skill['description']}"
for skill in self.skills.values()
)
def load(self, name: str) -> str:
skill = self.skills.get(name)
if skill:
return skill["content"]
available = ", ".join(self.skills) or "none"
return f"Error: Unknown skill '{name}'. Available: {available}"
SKILL_LOADER = SkillLoader(SKILLS_DIR)
def build_system_prompt() -> str:
return (
f"You are a coding agent at {WORKDIR}. Use tools to solve tasks. "
"Act, don't explain.\n\n"
f"Skills available:\n{SKILL_LOADER.catalog()}\n\n"
"Use load_skill to read the full instructions when a skill applies."
)
SYSTEM = build_system_prompt()
# -- Tools --
def run_bash(command: str) -> str:
try:
result = subprocess.run(
command, shell=True, cwd=WORKDIR,
capture_output=True, text=True, timeout=120,
)
output = (result.stdout + result.stderr).strip()
return output[:50000] if output else "(no output)"
except subprocess.TimeoutExpired:
return "Error: Timeout (120s)"
def run_read(path: str, limit: int | None = None) -> str:
try:
lines = (WORKDIR / path).resolve().read_text().splitlines()
if limit and limit < len(lines):
lines = lines[:limit] + [f"... ({len(lines) - limit} more lines)"]
return "\n".join(lines)
except Exception as e:
return f"Error: {e}"
def run_write(path: str, content: str) -> str:
try:
file_path = (WORKDIR / path).resolve()
file_path.parent.mkdir(parents=True, exist_ok=True)
file_path.write_text(content)
return f"Wrote {len(content)} bytes to {path}"
except Exception as e:
return f"Error: {e}"
def run_edit(path: str, old_text: str, new_text: str) -> str:
try:
file_path = (WORKDIR / path).resolve()
text = file_path.read_text()
if old_text not in text:
return f"Error: text not found in {path}"
file_path.write_text(text.replace(old_text, new_text, 1))
return f"Edited {path}"
except Exception as e:
return f"Error: {e}"
def run_glob(pattern: str) -> str:
import glob
try:
matches = []
for match in glob.glob(pattern, root_dir=WORKDIR):
if (WORKDIR / match).resolve().is_relative_to(WORKDIR):
matches.append(match)
return "\n".join(matches) if matches else "(no matches)"
except Exception as e:
return f"Error: {e}"
TOOLS = [
{"name": "bash", "description": "Run a shell command.",
"input_schema": {"type": "object", "properties": {"command": {"type": "string"}}, "required": ["command"]}},
{"name": "read_file", "description": "Read file contents.",
"input_schema": {"type": "object", "properties": {"path": {"type": "string"}, "limit": {"type": "integer"}}, "required": ["path"]}},
{"name": "write_file", "description": "Write content to a file.",
"input_schema": {"type": "object", "properties": {"path": {"type": "string"}, "content": {"type": "string"}}, "required": ["path", "content"]}},
{"name": "edit_file", "description": "Replace exact text in a file once.",
"input_schema": {"type": "object", "properties": {"path": {"type": "string"}, "old_text": {"type": "string"}, "new_text": {"type": "string"}}, "required": ["path", "old_text", "new_text"]}},
{"name": "glob", "description": "Find files matching a glob pattern.",
"input_schema": {"type": "object", "properties": {"pattern": {"type": "string"}}, "required": ["pattern"]}},
{"name": "load_skill", "description": "Load the full SKILL.md content by skill name.",
"input_schema": {"type": "object", "properties": {"name": {"type": "string"}}, "required": ["name"]}},
]
TOOL_HANDLERS = {
"bash": run_bash,
"read_file": run_read,
"write_file": run_write,
"edit_file": run_edit,
"glob": run_glob,
"load_skill": SKILL_LOADER.load,
}
# -- Hooks --
HOOKS = {"UserPromptSubmit": [], "PreToolUse": [], "PostToolUse": [], "Stop": []}
def register_hook(event: str, callback):
HOOKS[event].append(callback)
def trigger_hooks(event: str, *args):
for callback in HOOKS[event]:
result = callback(*args)
if result is not None:
return result
return None
DENY_LIST = ["rm -rf /", "sudo", "shutdown", "reboot", "mkfs", "dd if="]
DESTRUCTIVE = ["rm ", "> /etc/", "chmod 777"]
def permission_hook(block):
"""PreToolUse: block denied operations and ask about risky ones."""
if block.name == "bash":
command = block.input.get("command", "")
for pattern in DENY_LIST:
if pattern in command:
print(f"\n\033[31m[blocked] '{pattern}'\033[0m")
return "Permission denied by deny list"
for keyword in DESTRUCTIVE:
if keyword in command:
print("\n\033[33m[permission] Potentially destructive command\033[0m")
print(f" Tool: {block.name}({block.input})")
choice = input(" Allow? [y/N] ").strip().lower()
if choice not in ("y", "yes"):
return "Permission denied by user"
if block.name in ("read_file", "write_file", "edit_file"):
path = block.input.get("path", "")
if not (WORKDIR / path).resolve().is_relative_to(WORKDIR):
print("\n\033[33m[permission] Access outside workspace\033[0m")
print(f" Tool: {block.name}({block.input})")
choice = input(" Allow? [y/N] ").strip().lower()
if choice not in ("y", "yes"):
return "Permission denied by user"
return None
def log_hook(block):
"""PreToolUse: log every tool call."""
args_preview = str(list(block.input.values())[:2])[:60]
print(f"\033[90m[HOOK] {block.name}({args_preview})\033[0m")
return None
def large_output_hook(block, output):
"""PostToolUse: warn on large output."""
if len(str(output)) > 100000:
print(f"\033[33m[HOOK] Large output from {block.name}: {len(str(output))} chars\033[0m")
return None
def context_inject_hook(query: str):
"""UserPromptSubmit: log the working directory."""
print(f"\033[90m[HOOK] UserPromptSubmit: working in {WORKDIR}\033[0m")
return None
def summary_hook(messages: list):
"""Stop: print the number of tool results in this message list."""
tool_count = sum(
1
for message in messages
for block in (
message.get("content")
if isinstance(message.get("content"), list)
else []
)
if isinstance(block, dict) and block.get("type") == "tool_result"
)
print(f"\033[90m[HOOK] Stop: session used {tool_count} tool calls\033[0m")
return None
register_hook("UserPromptSubmit", context_inject_hook)
register_hook("PreToolUse", permission_hook)
register_hook("PreToolUse", log_hook)
register_hook("PostToolUse", large_output_hook)
register_hook("Stop", summary_hook)
def execute_tool(block) -> str:
blocked = trigger_hooks("PreToolUse", block)
if blocked:
return str(blocked)
handler = TOOL_HANDLERS.get(block.name)
try:
output = handler(**block.input) if handler else f"Unknown: {block.name}"
except Exception as e:
output = f"Error: {e}"
trigger_hooks("PostToolUse", block, output)
return str(output)
def agent_loop(messages: list):
while True:
response = client.messages.create(
model=MODEL,
system=SYSTEM,
messages=messages,
tools=TOOLS,
max_tokens=8000,
)
messages.append({"role": "assistant", "content": response.content})
tool_calls = [
block for block in response.content if block.type == "tool_use"
]
if not tool_calls:
force = trigger_hooks("Stop", messages)
if force:
messages.append({"role": "user", "content": force})
continue
return
results = []
for block in tool_calls:
output = execute_tool(block)
results.append({
"type": "tool_result",
"tool_use_id": block.id,
"content": output,
})
messages.append({"role": "user", "content": results})
if __name__ == "__main__":
print("s07: Skill Loading - catalog first, full content on demand")
print("Enter a question, press Enter to send. Type q to quit.\n")
history = []
while True:
try:
query = input("\033[36ms07 >> \033[0m")
except (EOFError, KeyboardInterrupt):
break
if query.strip().lower() in ("q", "exit", ""):
break
trigger_hooks("UserPromptSubmit", query)
history.append({"role": "user", "content": query})
agent_loop(history)
for block in history[-1]["content"]:
if getattr(block, "type", None) == "text":
print(block.text)
print()