Unify db api

engine/README.md

@@ -14,6 +14,57 @@ It is currently in an early, experimental stage.
 uvicorn app.main:app --reload --host 0.0.0.0 --port 8000
 ```
 
+使用 agent profile（推荐）
+
+```
+python -m app.main --agent-profile default
+```
+
+使用指定 YAML
+
+```
+python -m app.main --agent-config config/agents/default.yaml
+```
+
+Agent 配置路径优先级
+1. `--agent-config`
+2. `--agent-profile`（映射到 `config/agents/<profile>.yaml`）
+3. `AGENT_CONFIG_PATH`
+4. `AGENT_PROFILE`
+5. `config/agents/default.yaml`（若存在）
+
+说明
+- Agent 相关配置是严格模式：YAML 缺少必须项会直接报错，不会回退到 `.env` 或代码默认值。
+- 如果要引用环境变量，请在 YAML 显式写 `${ENV_VAR}`。
+- `siliconflow` 独立 section 已移除；请在 `agent.llm / agent.tts / agent.asr` 内通过 `provider`、`api_key`、`api_url`、`model` 配置。
+- 现在支持在 Agent YAML 中配置 `agent.tools`（列表），用于声明运行时可调用工具。
+- 工具配置示例见 `config/agents/tools.yaml`。
+
+## Backend Integration
+
+Engine runtime now supports adapter-based backend integration:
+
+- `BACKEND_MODE=auto|http|disabled`
+- `BACKEND_URL` + `BACKEND_TIMEOUT_SEC`
+- `HISTORY_ENABLED=true|false`
+
+Behavior:
+
+- `auto`: use HTTP backend only when `BACKEND_URL` is set, otherwise engine-only mode.
+- `http`: force HTTP backend; falls back to engine-only mode when URL is missing.
+- `disabled`: force engine-only mode (no backend calls).
+
+History write path is now asynchronous and buffered per session:
+
+- `HISTORY_QUEUE_MAX_SIZE`
+- `HISTORY_RETRY_MAX_ATTEMPTS`
+- `HISTORY_RETRY_BACKOFF_SEC`
+- `HISTORY_FINALIZE_DRAIN_TIMEOUT_SEC`
+
+This keeps turn processing responsive even when backend history APIs are slow/failing.
+
+Detailed notes: `docs/backend_integration.md`.
+
 测试
 
 ```
@@ -28,4 +79,4 @@ python mic_client.py
 
 `/ws` uses a strict `v1` JSON control protocol with binary PCM audio frames.
 
-See `/Users/wx44wx/.codex/worktrees/d817/AI-VideoAssistant/engine/docs/ws_v1_schema.md`.
+See `docs/ws_v1_schema.md`.