Backend: - FastAPI WebSocket /ws endpoint with streaming via LangGraph astream - LangGraph Supervisor connecting 3 mock agents (order_lookup, order_actions, fallback) - YAML Agent Registry with Pydantic validation and immutable configs - PostgresSaver checkpoint persistence via langgraph-checkpoint-postgres - Session TTL with 30-min sliding window and interrupt extension - LLM provider abstraction (Anthropic/OpenAI/Google) - Token usage + cost tracking callback handler - Input validation: message size cap, thread_id format, content length - Security: no hardcoded defaults, startup API key validation, no input reflection Frontend: - React 19 + TypeScript + Vite chat UI - WebSocket hook with reconnect + exponential backoff - Streaming token display with agent attribution - Interrupt approval/reject UI for write operations - Collapsible tool call viewer Testing: - 87 unit tests, 87% coverage (exceeds 80% requirement) - Ruff lint + format clean Infrastructure: - Docker Compose (PostgreSQL 16 + backend) - pyproject.toml with full dependency management
105 lines
3.6 KiB
Python
105 lines
3.6 KiB
Python
"""YAML Agent registry loader with validation."""
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from __future__ import annotations
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from pathlib import Path
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from typing import Literal
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import yaml
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from pydantic import BaseModel, field_validator
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class PersonalityConfig(BaseModel, frozen=True):
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tone: str = "professional and helpful"
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greeting: str = "Hello! How can I help you today?"
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escalation_message: str = "Let me connect you with a human agent."
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class AgentConfig(BaseModel, frozen=True):
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name: str
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description: str
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permission: Literal["read", "write"]
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personality: PersonalityConfig = PersonalityConfig()
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tools: list[str]
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@field_validator("name")
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@classmethod
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def name_not_empty(cls, v: str) -> str:
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if not v.strip():
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raise ValueError("Agent name must not be empty")
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return v.strip()
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@field_validator("tools")
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@classmethod
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def tools_not_empty(cls, v: list[str]) -> list[str]:
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if not v:
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raise ValueError("Agent must have at least one tool")
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return v
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class AgentRegistry:
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"""Immutable registry of agent configurations loaded from YAML."""
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def __init__(self, agents: tuple[AgentConfig, ...]) -> None:
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self._agents = {agent.name: agent for agent in agents}
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@classmethod
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def load(cls, yaml_path: str | Path) -> AgentRegistry:
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"""Load and validate agent configurations from a YAML file."""
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path = Path(yaml_path)
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if not path.exists():
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raise FileNotFoundError(f"Agent config file not found: {path}")
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raw_text = path.read_text(encoding="utf-8")
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if not raw_text.strip():
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raise ValueError(f"Agent config file is empty: {path}")
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try:
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data = yaml.safe_load(raw_text)
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except yaml.YAMLError as exc:
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msg = f"Invalid YAML in {path}"
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if hasattr(exc, "problem_mark") and exc.problem_mark is not None:
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mark = exc.problem_mark
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msg += f" at line {mark.line + 1}, column {mark.column + 1}"
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raise ValueError(msg) from exc
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if not isinstance(data, dict) or "agents" not in data:
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raise ValueError(f"Agent config must have a top-level 'agents' key in {path}")
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raw_agents = data["agents"]
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if not isinstance(raw_agents, list) or not raw_agents:
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raise ValueError(f"'agents' must be a non-empty list in {path}")
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agents: list[AgentConfig] = []
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seen_names: set[str] = set()
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for i, raw in enumerate(raw_agents):
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if not isinstance(raw, dict):
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raise ValueError(f"Agent at index {i} must be a mapping in {path}")
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try:
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agent = AgentConfig(**raw)
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except Exception as exc:
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raise ValueError(f"Invalid agent config at index {i} in {path}: {exc}") from exc
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if agent.name in seen_names:
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raise ValueError(f"Duplicate agent name '{agent.name}' in {path}")
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seen_names.add(agent.name)
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agents.append(agent)
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return cls(agents=tuple(agents))
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def get_agent(self, name: str) -> AgentConfig:
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if name not in self._agents:
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available = ", ".join(sorted(self._agents.keys()))
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raise KeyError(f"Agent '{name}' not found. Available: {available}")
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return self._agents[name]
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def list_agents(self) -> tuple[AgentConfig, ...]:
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return tuple(self._agents.values())
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def get_agents_by_permission(self, permission: str) -> tuple[AgentConfig, ...]:
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return tuple(a for a in self._agents.values() if a.permission == permission)
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def __len__(self) -> int:
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return len(self._agents)
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