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董宏凯andCursor a9d66536c3 fix: avoid MySQL thread_meta refresh races and harden roundtable bootstrap
Skip post-commit ORM refresh on threads_meta creates so concurrent MySQL
read/write-split deployments no longer fail with Could not refresh instance;
clean up partial roundtable threads on checkpoint failure, and ship related
position-roundtable/frontend build fixes.

Co-authored-by: Cursor <cursoragent@cursor.com>
2026-07-31 21:00:56 +08:00

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# DeerFlow Backend
DeerFlow is a LangGraph-based AI super agent with sandbox execution, persistent memory, and extensible tool integration. The backend enables AI agents to execute code, browse the web, manage files, delegate tasks to subagents, and retain context across conversations - all in isolated, per-thread environments.
---
## Architecture
```
┌──────────────────────────────────────┐
│ Nginx (Port 2026) │
│ Unified reverse proxy │
└───────┬──────────────────┬───────────┘
│ │
/api/langgraph/* │ │ /api/* (other)
▼ ▼
┌────────────────────┐ ┌────────────────────────┐
│ LangGraph Server │ │ Gateway API (8001) │
│ (Port 2024) │ │ FastAPI REST │
│ │ │ │
│ ┌────────────────┐ │ │ Models, MCP, Skills, │
│ │ Lead Agent │ │ │ Memory, Uploads, │
│ │ ┌──────────┐ │ │ │ Artifacts │
│ │ │Middleware│ │ │ └────────────────────────┘
│ │ │ Chain │ │ │
│ │ └──────────┘ │ │
│ │ ┌──────────┐ │ │
│ │ │ Tools │ │ │
│ │ └──────────┘ │ │
│ │ ┌──────────┐ │ │
│ │ │Subagents │ │ │
│ │ └──────────┘ │ │
│ └────────────────┘ │
└────────────────────┘
```
**Request Routing** (via Nginx):
- `/api/langgraph/*` → LangGraph Server - agent interactions, threads, streaming
- `/api/*` (other) → Gateway API - models, MCP, skills, memory, artifacts, uploads, thread-local cleanup
- `/` (non-API) → Frontend - Next.js web interface
---
## Core Components
### Lead Agent
The single LangGraph agent (`lead_agent`) is the runtime entry point, created via `make_lead_agent(config)`. It combines:
- **Dynamic model selection** with thinking and vision support
- **Middleware chain** for cross-cutting concerns (9 middlewares)
- **Tool system** with sandbox, MCP, community, and built-in tools
- **Subagent delegation** for parallel task execution
- **System prompt** with skills injection, memory context, and working directory guidance
### Middleware Chain
Middlewares execute in strict order, each handling a specific concern:
| # | Middleware | Purpose |
|---|-----------|---------|
| 1 | **ThreadDataMiddleware** | Creates per-thread isolated directories (workspace, uploads, outputs) |
| 2 | **UploadsMiddleware** | Injects newly uploaded files into conversation context |
| 3 | **SandboxMiddleware** | Acquires sandbox environment for code execution |
| 4 | **SummarizationMiddleware** | Reduces context when approaching token limits (optional) |
| 5 | **TodoListMiddleware** | Tracks multi-step tasks in plan mode (optional) |
| 6 | **TitleMiddleware** | Auto-generates conversation titles after first exchange |
| 7 | **MemoryMiddleware** | Queues conversations for async memory extraction |
| 8 | **ViewImageMiddleware** | Injects image data for vision-capable models (conditional) |
| 9 | **ClarificationMiddleware** | Intercepts clarification requests and interrupts execution (must be last) |
### Sandbox System
Per-thread isolated execution with virtual path translation:
- **Abstract interface**: `execute_command`, `read_file`, `write_file`, `list_dir`
- **Providers**: `LocalSandboxProvider` (filesystem) and `AioSandboxProvider` (Docker, in community/)
- **Virtual paths**: `/mnt/user-data/{workspace,uploads,outputs}` → thread-specific physical directories
- **Skills path**: `/mnt/skills` → `deer-flow/skills/` directory
- **Skills loading**: Recursively discovers nested `SKILL.md` files under `skills/{public,custom}` and preserves nested container paths
- **WeKnora retrieval skill**: `skills/custom/weknora-knowledge-search` pairs a concise Skill with a stdio MCP server. It retrieves tenant-scoped WeKnora document/FAQ passages through the public API, groups multi-KB calls by embedding model, optionally searches Wiki pages, and can use the local reranker. It does not reject a KB solely because the legacy list API reports `chunk_count=0`; hybrid-search remains the source of truth. For WeKnora's explicit DeerFlow sharing mode, configure `WEKNORA_DEERFLOW_SHARE_TOKEN_FILE`: the MCP uses the restricted `/api/v1/deerflow/*` capability API and can only list/search knowledge bases whose owner enabled sharing; it never receives a user bearer token. Shared document results now contain a credential-free `url` pointer; the source card's “查看原文” dialog calls DeerFlow's authenticated `/api/weknora/source-context` proxy, which retrieves the hit plus two adjacent chunks while keeping the share token server-side. Shared mode currently excludes Wiki pages. Otherwise use `WEKNORA_API_KEY_FILE` for scoped-key deployments or `WEKNORA_BEARER_TOKEN_FILE` for legacy deployments; never put any credential in `SKILL.md` or a chat prompt.
- **File-write safety**: `str_replace` serializes read-modify-write per `(sandbox.id, path)` so isolated sandboxes keep concurrency even when virtual paths match
- **Tools**: `bash`, `ls`, `read_file`, `write_file`, `str_replace` (`bash` is disabled by default when using `LocalSandboxProvider`; use `AioSandboxProvider` for isolated shell access)
### Subagent System
Async task delegation with concurrent execution:
- **Built-in agents**: `general-purpose` (full toolset) and `bash` (command specialist, exposed only when shell access is available)
- **Concurrency**: Max 3 subagents per turn, 15-minute timeout
- **Execution**: Background thread pools with status tracking and SSE events
- **Flow**: Agent calls `task()` tool → executor runs subagent in background → polls for completion → returns result
### Memory System
LLM-powered persistent context retention across conversations:
- **Automatic extraction**: Analyzes conversations for user context, facts, and preferences
- **Structured storage**: User context (work, personal, top-of-mind), history, and confidence-scored facts
- **Debounced updates**: Batches updates to minimize LLM calls (configurable wait time)
- **System prompt injection**: Top facts + context injected into agent prompts
- **Storage**: JSON file with mtime-based cache invalidation
### Tool Ecosystem
| Category | Tools |
|----------|-------|
| **Sandbox** | `bash`, `ls`, `read_file`, `write_file`, `str_replace` |
| **Built-in** | `present_files`, `ask_clarification`, `view_image`, `task` (subagent) |
| **Community** | Tavily (web search), Jina AI (web fetch), Firecrawl (scraping), DuckDuckGo (image search) |
| **MCP** | Any Model Context Protocol server (stdio, SSE, HTTP transports) |
| **Skills** | Domain-specific workflows injected via system prompt |
### Gateway API
FastAPI application providing REST endpoints for frontend integration:
| Route | Purpose |
|-------|---------|
| `GET /api/models` | List available LLM models |
| `GET/PUT /api/mcp/config` | Manage MCP server configurations |
| `GET/PUT /api/skills` | List and manage skills |
| `POST /api/skills/install` | Install skill from `.skill` archive |
| `GET/POST /api/agents` | List visible agents or create a user-owned agent |
| `GET/PUT/DELETE /api/agents/{id}` | Read, update, or delete an id-addressed agent |
| `GET/POST/PUT/DELETE /api/roundtable-chains` | Manage user-owned roundtable business chains; each seat may optionally carry `position_id` for the separate position-collaboration workspace (the original roundtable ignores it) |
| `GET/PUT /api/business-mapping` | Read global business mappings. Updates to 3Q/6BF/7BF require an administrator; the 8BF public business-chain mapping is maintained exclusively by the trusted `lqq` account (derived from the authenticated email prefix). |
| `GET/POST/PUT /api/position-roundtable/sessions` | Standalone position-collaboration sessions: freeze task/intent/chain snapshots, index one direct-agent node per seat, build upstream handoff context (including bounded UTF-8 excerpts of text artifacts), and make archived sessions read-only without invoking the original roundtable coordinator or jobs. Built-in summary/action-plan completion mirrors visible report text into a Markdown artifact when a model omits its final `write_file` call. `POST /sessions/{id}/nodes/{nodeKey}/reject` accepts an optional reason, marks the rejected delivery for rework, and invalidates affected downstream deliveries so they are regenerated in order. The same router is also mounted at `/api/multi-agent/position-roundtable/*` for intranet gateways that only forward the established multi-agent namespace; the compatibility mount is intentionally omitted from OpenAPI. |
| `GET /api/memory` | Retrieve memory data |
| `POST /api/memory/reload` | Force memory reload |
| `GET /api/memory/config` | Memory configuration |
| `GET /api/memory/status` | Combined config + data |
| `POST /api/threads/{id}/uploads` | Upload files (auto-converts PDF/PPT/Excel/Word to Markdown, rejects directory paths) |
| `GET /api/threads/{id}/uploads/list` | List uploaded files |
| `DELETE /api/threads/{id}` | Delete DeerFlow-managed local thread data after LangGraph thread deletion; unexpected failures are logged server-side and return a generic 500 detail |
| `GET /api/threads/{id}/artifacts/{path}` | Serve generated artifacts |
| `POST /api/ai-writing/sample/extract` | Extract text from Word/PDF/Markdown/TXT samples for AI-writing imitation mode |
| `POST /cop/saveSuperiorTask` | TaskCOP compatibility API (DeerFlow Bearer/session authentication required): create a situation-overview task with a sequential four-digit id (`0001`, `0002`, ...) and return the legacy `{state, msg, data}` envelope |
| `POST /api/taskcop/import/tasks` | TaskCOP compatibility API (authenticated): import tasks from a JSON array or `tasks`/`records` envelope; every row's supplied `id`/`taskId` is authoritative and a duplicate id completely replaces the stored task |
| `DELETE /cop/tasks/{task_id}` | TaskCOP compatibility API (authenticated): delete one task and its task-scoped situation-report document |
| `GET /taskAnalyseSearch/cop-task-three-list` | TaskCOP compatibility API (authenticated): paginated task list for the situation-overview sentiment page (`content`, `taskStatus`, `taskDirection`, `startTime`, `endTime`) |
| `GET/POST/PUT /api/task-reports/by-task/{task_id}` | Shared task-scoped situation-report detail. Query, first save, and full update all use the legacy-compatible `{state, msg, data:[{id, taskId, createTime, updateTime, sessionId, contentJson, categoryType}]}` shape; `contentJson` is preserved as a JSON string. Saving a non-empty report automatically moves the matching TaskCOP task to status `25` (the legacy list's “已完成” state). |
| `POST /api/task-reports/import/by-task/{task_id}` | TaskCOP detail import (authenticated): accept a `sq-report-mock.json`-compatible `data`/`records` array and atomically replace the selected task's full report. The path task id overrides task ids inside the file. |
The separately deployed TaskCOP Vue app uses `POST /api/v1/auth/login/username` directly (its `username`, `userId`, or `yUserId` URL parameter identifies the user), so this compatibility flow does not depend on the retired Consumer login service. It calls the Gateway address configured as `b1ConsumerUrl` directly; it does not use a Vite `/api` reverse proxy. An empty TaskCOP store remains empty; task data is introduced through normal creation or the JSON import API. The Gateway CORS middleware always merges the local TaskCOP Vite origins `http://localhost:8080` and `http://127.0.0.1:8080`, including when `GATEWAY_CORS_ORIGINS` is set for another frontend. `scripts/env.sh` also includes them in its startup default. For a deployment, set `GATEWAY_CORS_ORIGINS` to the exact additional frontend origins that are allowed to call the Gateway.
AI writing supports a sample-imitation mode: the frontend can upload or paste a sample article, the Gateway extracts text for document files, and the `ai_writing` graph runs a `sample_analyzer` node before normal intent/research/outline/draft stages. The resulting style profile is injected into outline and draft prompts with explicit guardrails against copying source sentences, facts, names, or data.
### Custom Agents
Custom agents are indexed in the `agents` database table. The `id` column is the stable runtime identifier and filesystem directory name (`.deer-flow/agents/{id}/SOUL.md`); `name` is display-only, may be Chinese, and may be duplicated. Rows with `user_id = NULL` are built-in agents, user rows are private unless `published = true`, and users can only update or delete agents they created.
### AI Writing Intranet Retrieval
AI 写作的「知识库检索」会直连 `ai_writing.intranet_search_url` 内网 ES/知识库接口,并默认跳过代理环境变量和 HTTPS 证书校验,适配自签名或内部 CA 证书的内网服务。需要强校验时可在 `config.yaml` 里设置 `ai_writing.intranet_verify_ssl: true`。通用检索里的非内置技能在 `ai_writing.researcher_skill_agent: true` 时会用真实 agent 运行时执行技能:以 `ai-writing-researcher` 身份读取该技能的 `SKILL.md`,并按技能要求通过 `bash` 运行脚本,弱模型也会在本轮任务里收到明确的读文件和脚本执行指令。
### IM Channels
The IM bridge supports Feishu, Slack, and Telegram. Slack and Telegram still use the final `runs.wait()` response path, while Feishu now streams through `runs.stream(["messages-tuple", "values"])` and updates a single in-thread card in place.
For Feishu card updates, DeerFlow stores the running card's `message_id` per inbound message and patches that same card until the run finishes, preserving the existing `OK` / `DONE` reaction flow.
---
## Quick Start
### Prerequisites
- Python 3.12+
- [uv](https://docs.astral.sh/uv/) package manager
- API keys for your chosen LLM provider
### Installation
```bash
cd deer-flow
# Copy configuration files
cp config.example.yaml config.yaml
# Install backend dependencies
cd backend
make install
```
### Configuration
Edit `config.yaml` in the project root:
```yaml
models:
- name: gpt-4o
display_name: GPT-4o
use: langchain_openai:ChatOpenAI
model: gpt-4o
api_key: $OPENAI_API_KEY
supports_thinking: false
supports_vision: true
- name: gpt-5-responses
display_name: GPT-5 (Responses API)
use: langchain_openai:ChatOpenAI
model: gpt-5
api_key: $OPENAI_API_KEY
use_responses_api: true
output_version: responses/v1
supports_vision: true
```
Set your API keys:
```bash
export OPENAI_API_KEY="your-api-key-here"
```
### Running
**Full Application** (from project root):
```bash
make dev # Starts LangGraph + Gateway + Frontend + Nginx
```
Access at: http://localhost:2026
**Backend Only** (from backend directory):
```bash
# Terminal 1: LangGraph server
make dev
# Terminal 2: Gateway API
make gateway
```
Direct access: LangGraph at http://localhost:2024, Gateway at http://localhost:8001
---
## Project Structure
```
backend/
├── src/
│ ├── agents/ # Agent system
│ │ ├── lead_agent/ # Main agent (factory, prompts)
│ │ ├── middlewares/ # 9 middleware components
│ │ ├── memory/ # Memory extraction & storage
│ │ └── thread_state.py # ThreadState schema
│ ├── gateway/ # FastAPI Gateway API
│ │ ├── app.py # Application setup
│ │ └── routers/ # 6 route modules
│ ├── sandbox/ # Sandbox execution
│ │ ├── local/ # Local filesystem provider
│ │ ├── sandbox.py # Abstract interface
│ │ ├── tools.py # bash, ls, read/write/str_replace
│ │ └── middleware.py # Sandbox lifecycle
│ ├── subagents/ # Subagent delegation
│ │ ├── builtins/ # general-purpose, bash agents
│ │ ├── executor.py # Background execution engine
│ │ └── registry.py # Agent registry
│ ├── tools/builtins/ # Built-in tools
│ ├── mcp/ # MCP protocol integration
│ ├── models/ # Model factory
│ ├── skills/ # Skill discovery & loading
│ ├── config/ # Configuration system
│ ├── community/ # Community tools & providers
│ ├── reflection/ # Dynamic module loading
│ └── utils/ # Utilities
├── docs/ # Documentation
├── tests/ # Test suite
├── langgraph.json # LangGraph server configuration
├── pyproject.toml # Python dependencies
├── Makefile # Development commands
└── Dockerfile # Container build
```
---
## Configuration
### Main Configuration (`config.yaml`)
Place in project root. Config values starting with `$` resolve as environment variables.
Key sections:
- `models` - LLM configurations with class paths, API keys, thinking/vision flags
- `tools` - Tool definitions with module paths and groups
- `tool_groups` - Logical tool groupings
- `sandbox` - Execution environment provider
- `skills` - Skills directory paths
- `title` - Auto-title generation settings
- `summarization` - Context summarization settings
- `subagents` - Subagent system (enabled/disabled)
- `memory` - Memory system settings (enabled, storage, debounce, facts limits)
Provider note:
- `models[*].use` references provider classes by module path (for example `langchain_openai:ChatOpenAI`).
- If a provider module is missing, DeerFlow now returns an actionable error with install guidance (for example `uv add langchain-google-genai`).
### Browser CORS
The Gateway permits the local TaskCOP/Vite development origins
`http://localhost:8080` and `http://127.0.0.1:8080` with credentials. For a
separate deployed frontend, set `GATEWAY_CORS_ORIGINS` to its exact origin
(including scheme and port), for example `http://47.88.25.99:7010`. Explicit
origins are used in addition to the local TaskCOP development origins.
### Extensions Configuration (`extensions_config.json`)
MCP servers and skill states in a single file:
```json
{
"mcpServers": {
"github": {
"enabled": true,
"type": "stdio",
"command": "npx",
"args": ["-y", "@modelcontextprotocol/server-github"],
"env": {"GITHUB_TOKEN": "$GITHUB_TOKEN"}
},
"secure-http": {
"enabled": true,
"type": "http",
"url": "https://api.example.com/mcp",
"oauth": {
"enabled": true,
"token_url": "https://auth.example.com/oauth/token",
"grant_type": "client_credentials",
"client_id": "$MCP_OAUTH_CLIENT_ID",
"client_secret": "$MCP_OAUTH_CLIENT_SECRET"
}
}
},
"skills": {
"pdf-processing": {"enabled": true}
}
}
```
### Environment Variables
- `DEER_FLOW_CONFIG_PATH` - Override config.yaml location
- `DEER_FLOW_EXTENSIONS_CONFIG_PATH` - Override extensions_config.json location
- Model API keys: `OPENAI_API_KEY`, `ANTHROPIC_API_KEY`, `DEEPSEEK_API_KEY`, etc.
- Tool API keys: `TAVILY_API_KEY`, `GITHUB_TOKEN`, etc.
### LangSmith Tracing
DeerFlow has built-in [LangSmith](https://smith.langchain.com) integration for observability. When enabled, all LLM calls, agent runs, tool executions, and middleware processing are traced and visible in the LangSmith dashboard.
**Setup:**
1. Sign up at [smith.langchain.com](https://smith.langchain.com) and create a project.
2. Add the following to your `.env` file in the project root:
```bash
LANGSMITH_TRACING=true
LANGSMITH_ENDPOINT=https://api.smith.langchain.com
LANGSMITH_API_KEY=lsv2_pt_xxxxxxxxxxxxxxxx
LANGSMITH_PROJECT=xxx
```
**Legacy variables:** The `LANGCHAIN_TRACING_V2`, `LANGCHAIN_API_KEY`, `LANGCHAIN_PROJECT`, and `LANGCHAIN_ENDPOINT` variables are also supported for backward compatibility. `LANGSMITH_*` variables take precedence when both are set.
### Langfuse Tracing
DeerFlow also supports [Langfuse](https://langfuse.com) observability for LangChain-compatible runs.
Add the following to your `.env` file:
```bash
LANGFUSE_TRACING=true
LANGFUSE_PUBLIC_KEY=pk-lf-xxxxxxxxxxxxxxxx
LANGFUSE_SECRET_KEY=sk-lf-xxxxxxxxxxxxxxxx
LANGFUSE_BASE_URL=https://cloud.langfuse.com
```
If you are using a self-hosted Langfuse deployment, set `LANGFUSE_BASE_URL` to your Langfuse host.
### Dual Provider Behavior
If both LangSmith and Langfuse are enabled, DeerFlow initializes and attaches both callbacks so the same run data is reported to both systems.
If a provider is explicitly enabled but required credentials are missing, or the provider callback cannot be initialized, DeerFlow raises an error when tracing is initialized during model creation instead of silently disabling tracing.
**Docker:** In `docker-compose.yaml`, tracing is disabled by default (`LANGSMITH_TRACING=false`). Set `LANGSMITH_TRACING=true` and/or `LANGFUSE_TRACING=true` in your `.env`, together with the required credentials, to enable tracing in containerized deployments.
---
## Development
### Commands
```bash
make install # Install dependencies
make dev # Run LangGraph server (port 2024)
make gateway # Run Gateway API (port 8001)
make lint # Run linter (ruff)
make format # Format code (ruff)
```
### Code Style
- **Linter/Formatter**: `ruff`
- **Line length**: 240 characters
- **Python**: 3.12+ with type hints
- **Quotes**: Double quotes
- **Indentation**: 4 spaces
### Testing
```bash
uv run pytest
```
### Runtime appearance themes
The admin appearance settings are persisted in `.deer-flow/system_settings.json`.
Besides the built-in themes, an administrator can create up to 12 runtime
themes through `PUT /api/system-settings/appearance`. Each theme stores a
safe six-digit `primary` colour, an optional primary-button `text_color`,
`light`/`dark` mode, name, enabled flag and sort order. The frontend derives
the rest of the visual tokens; the optional `overrides` object only exposes
ten interaction colours (`button_hover`, `navigation_gradient_start`,
`navigation_gradient_end`, `selected_background`, `border`, `muted`,
`muted_text`, `destructive`, `brand_title`, `primary_foreground`) for
exceptional brand requirements. The two navigation values override the
automatically derived top-bar gradient. A custom theme id
must use the `custom-theme-` prefix. Disabled or removed custom themes cannot
remain the system default and automatically fall back to `light`.
---
## Technology Stack
- **LangGraph** (1.0.6+) - Agent framework and multi-agent orchestration
- **LangChain** (1.2.3+) - LLM abstractions and tool system
- **FastAPI** (0.115.0+) - Gateway REST API
- **langchain-mcp-adapters** - Model Context Protocol support
- **agent-sandbox** - Sandboxed code execution
- **markitdown** - Multi-format document conversion
- **tavily-python** / **firecrawl-py** - Web search and scraping
---
## Documentation
- [Configuration Guide](docs/CONFIGURATION.md)
- [Architecture Details](docs/ARCHITECTURE.md)
- [API Reference](docs/API.md)
- [Offline Docker wheelhouse deployment (ZH)](../README.md)
- [File Upload](docs/FILE_UPLOAD.md)
- [Path Examples](docs/PATH_EXAMPLES.md)
- [Context Summarization](docs/summarization.md)
- [Plan Mode](docs/plan_mode_usage.md)
- [Backend Run/Stop Guide (ZH)](docs/BACKEND_RUN_STOP_ZH.md)
- [Setup Guide](docs/SETUP.md)
---
## License
See the [LICENSE](../LICENSE) file in the project root.
## Contributing
See [CONTRIBUTING.md](CONTRIBUTING.md) for contribution guidelines.
## Position roundtable durable history
The position-roundtable workflow stores database-owned recovery snapshots for
Step-1 intent chat, every position-node chat, the summary/action-plan chats,
unsent composer drafts, and generated text deliverables. LangGraph checkpoints
remain the execution source, but SQL history continues to render after a
checkpoint or sandbox-output volume is replaced. Apply Alembic revision
`20260723_05` (or simply upgrade to `head`) before deploying this version.
Its live intent conversation still uses the shared `/api/intent/init` and
`/api/intent/stream` endpoints used by the original multi-agent roundtable.
`/api/intent/init` creates its empty thread directly through the in-process
thread store/checkpointer, matching multi-agent initialization and avoiding a
deployment-sensitive `127.0.0.1:<gateway-port>` loopback. If initial checkpoint
creation fails or is cancelled, bootstrap removes both the partial checkpoint and
its thread metadata row. Thread metadata creation issues no post-commit ORM
read-back on any code path: all returned fields are assigned before commit, and
skipping the extra read keeps a MySQL read/write-splitting endpoint from sending
it to a lagging replica (which fails the request with
`Could not refresh instance`). Only the
recovery snapshot layer is position-specific. Deployments must expose
either `/api/position-roundtable/*` or the compatibility mirror
`/api/multi-agent/position-roundtable/*`; updated clients probe both and only
retry when the first response is the framework/proxy-level `404 Not Found`.
## Position-roundtable role directory
The position-roundtable work views are persisted separately from organisation
positions/RBAC in `position_roles`. Gateway startup idempotently inserts the
four built-in ids (testing analysis, organisation test, solution design and
comprehensive test), but only when an id is missing: administrator changes to
the name, order, enabled state or role type are never overwritten.
`GET /api/position-roles` is consumed by the workbench and `PUT
/api/position-roles` is administrator-only. Exactly one enabled `intent` role
is required. It is the initial intent-identification workspace and owns the
summary/action-plan closing agents. Built-in rows retain stable ids so
historical chain nodes remain readable; they can be edited or disabled but not
deleted. Custom roles may be freely added or removed.