Synapse

The open-source coding agent that lives in your terminal — built on LangChain Deep Agents. Ask it to fix a test, refactor a module, or carry a goal across turns until it is done.

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Synapse is a terminal-first coding-agent runtime. Unlike a one-shot "run this and reply" prompt, it is designed for sessions that last more than a few turns: a responsive TUI that keeps the timeline, tool calls, and context usage visible; token-aware handling of tool output; and persistent goals that keep the agent working until the work is actually done.

Install

One command, no clone required:

uv tool install synapse-cli-agent

Windows users can also install via Scoop (single-file executable, auto-updated through checkver): add the bucket, then install:

scoop bucket add synapse https://github.com/alex8224/synapse-agent
scoop install synapse

Or install directly from the manifest URL:

scoop install https://raw.githubusercontent.com/alex8224/synapse-agent/main/bucket/synapse.json

Then start the TUI from anywhere:

synapse tui -w .

To run the standalone foreground runtime daemon (S8), use the installed synapse-runtime command or the module form. It prints one ready JSON metadata line to stdout after binding; the token is generated in the private state directory and is never printed.

synapse-runtime --state-dir ~/.synapse/runtime --host 127.0.0.1 --port 0
# or: python -m synapse.runtime.daemon --state-dir ~/.synapse/runtime --port 0

Use --token-file PATH to select a deployment-specific token file. The daemon uses a held lock in the state directory, runs in the foreground, and stops on SIGINT/SIGTERM. It does not provide install/start/stop/status controls and does not migrate the CLI, TUI, or ACP consumers.

Web 控制台（React，正式宿主）

web/ 是 React + TypeScript 单页控制台。生产路径使用 synapse web-console 子命令（薄 aiohttp 进程：静态产物 + 配对 API + WebSocket 中继）， 不依赖 Vite 开发中间件承担业务；Vite 只在开发时做静态热更新与受控代理。旧的 synapse-web（textual-serve 把 TUI 放进浏览器）入口保持不变、仍可用，与正式宿主 语义不同。

先同步依赖与前端产物再启动。一条命令即可：宿主默认会在该 --state-dir 下没有 运行中 daemon 时自己拉起一个（--port 0 由内核分配），并在自己退出时把它停掉； 已经有一个在跑则直接复用、绝不动它。想要「daemon 必须由我亲自启动」就加 --no-start-runtime；给了 --runtime-port 也视为「用那个 daemon」，不会另起。

uv sync                                   # 源码检出必做：console script 由安装步骤生成
cd web && npm ci && npm run build && cd ..
# 一条命令：宿主按需拉起/复用 daemon（wheel 已内置前端产物）
synapse web-console --workspace . \
  --state-dir ~/.synapse/runtime --port 8080

仍然可以把 daemon 当作独立服务来跑（服务化部署、或想让它跨控制台存活）：先在一个 终端启动它，再启动宿主——宿主会发现它并复用。

synapse-runtime --state-dir ~/.synapse/runtime --host 127.0.0.1 --port 0

synapse web-console 与 synapse-runtime 都由安装步骤（uv sync）生成。未同步的源码检出里， 可以使用等价的模块形式：

uv run --no-sync python -m synapse.web_console.entry --workspace . \
  --state-dir ~/.synapse/runtime --port 8080

宿主的自动拉起只覆盖它自己启动的 daemon：正常退出（Ctrl+C / SIGTERM）会连带停掉； 被强杀（任务管理器、taskkill /F）则 daemon 会留下来继续跑（它是服务，下次启动会被 复用而不是重复拉起）。两条命令行形式都是前台常驻进程，前台启动会占住调用它的终端： 交互使用各开一个终端；脚本/自动化 （含 agent）必须非阻塞启动——让子进程脱离调用方进程树，并把 stdout/stderr 重定向到 文件。PowerShell 下从 shell 直接 Start-Process -RedirectStandardOutput ... 会因 子进程继承 stdout 管道而卡住调用方（直到进程退出才返回），可行做法是 cmd.exe /c 包一层带重定向的脚本，再经 Win32_Process.Create 脱离启动：

$log = "$env:TEMP\synapse-webui"; New-Item -ItemType Directory -Force $log | Out-Null
# $log\start-console.cmd 内一行（@echo off 之后）：
#   "<repo>\.venv\Scripts\python.exe" -m synapse.web_console.entry --workspace "<repo>" ^
#     --static-dir "<repo>\web\dist" --state-dir "%USERPROFILE%\.synapse\runtime" --port 8080 ^
#     > "%TEMP%\synapse-webui\console.out" 2> "%TEMP%\synapse-webui\console.err"
Invoke-CimMethod -ClassName Win32_Process -MethodName Create -Arguments @{
  CommandLine = "cmd.exe /c `"$log\start-console.cmd`""; CurrentDirectory = "$PWD" }

配对码随后从 $log\console.err 读取（前台运行时直接出现在宿主 stderr）。

宿主启动时 stdout 恰好一行 JSON 元数据，配对码只出现在 stderr：

synapse web-console: pairing code XXXXXXXX (expires in 300s; open http://127.0.0.1:8080/ and enter it)

打开 http://127.0.0.1:8080/ 输入该 8 位配对码完成配对（单次使用，默认 300s 过期）。会话 cookie 默认只在 POST /api/pair 成功时签发；GET /api/bootstrap 已删除， 恒返回 405 且不签发 cookie。

本地调试（例如用 CDP/devtools 驱动控制台、不想每次重启宿主都重新输码）可以显式加 --no-pairing（默认关闭）：宿主不创建、也不打印配对码，GET /api/session 会为任何同源 loopback 浏览器直接签发会话（200 + Set-Cookie，属性与配对签发一致），stderr 改打一条 WARNING pairing is disabled (--no-pairing) …，stdout 元数据行的 pairing_required 变为 false；POST /api/pair 在该模式下返回 400，跨站 POST 仍被 403 拒绝。它只保护到「同源 loopback 浏览器」这一层（Host/Origin/Sec-Fetch-Site 都是客户端可伪造的头，只算纵深 防御），没有任何持有证明，因此只用于本机调试，不要用在共享或对外暴露的控制台上。其余 边界不变：会话只在宿主进程内存、上限 8、默认 12h TTL，宿主重启即失效（该模式下由下一次 会话探测自动重新签发），/runtime-ws 中继仍要求有效会话 cookie，daemon bearer 依旧不出现 在任何 HTTP 响应、stdout 或中继帧里。

宿主默认且仅支持 loopback（127.0.0.1/localhost/::1，配置层强制），是 loopback 单用户工具，不是公网多租户安全产品。已建立的边界：浏览器始终拿不到 daemon bearer token/env/model secret——宿主服务端持有 token 并以 Authorization: Bearer 连接 daemon，再中继 JSON-RPC 帧（唯一例外：指向非宿主自身项目的请求由宿主以 typed not_found 拒绝、不进入 daemon，边界与残余风险见 docs/web-console/formal-host.md §4.1）；URL 不再携带 token，前端也不再硬编码 token/project/workspace。配对码只存在于宿主进程内存与 stderr，不落盘、不进 stdout JSON。/runtime-ws 中继在升级前要求 Host 与 Origin 精确匹配（含端口）+ 有效会话 cookie；浏览器断线不会取消 daemon 中仍在运行的 turn。静态服务带路径遍历/符号 链接逃逸防护、帧大小上界、SPA 回退与 no-store/asset immutable 缓存规则；中继出站 缓冲另有显式上界（64 帧 / 8 MiB，取先到者），超限即断开并计数。已配对浏览器可只读 GET /api/runtime-status 获取 daemon 端点、state dir 与 start synapse-runtime 提示 （响应不含 token；POST → 405）。

明确不承诺（详见 docs/web-console/formal-host.md §4、§9）：Host/Origin/ Sec-Fetch-Site 都是客户端可伪造的头，只算纵深防御，默认模式下真正的门是配对码 （显式 --no-pairing 的豁免见上，它没有任何持有证明）；本切片不支持 TLS/反向代理（外部端口 ≠ 绑定端口）；会话不持久化，宿主重启后需重新配对 （--no-pairing 下由下一次会话探测自动重新签发，仍非持久化）； 会话 TTL 到期不主动断开已建立的中继；中继缓冲上界是进程内上界（不含 aiohttp/内核 socket 缓冲，不等于进程 RSS 上界）；跨项目拒绝对不可读/非文本帧 fail-open，且白名单与 protocol.decode_params 无源码级绑定，安全性依赖 daemon 的 严格校验；历史投影与实时 broker 之间不承诺跨存储原子一致（见 docs/sessions.md）。

开发模式（仅热更新与受控代理，不经中间件读 token）：

synapse web-console --workspace . --static-dir web/dist --port 8080 &
cd web && npm run dev     # 打开 http://127.0.0.1:5173

Vite 只把 /api 与 /runtime-ws 代理到宿主，并把转发请求的 Origin 重写为宿主 origin；它不直连 daemon、不注入任何凭据、不读 token 文件，server.host 保持 loopback 默认值，因此不构成认证旁路，宿主也不因 dev 放宽任何校验。dev 下同样需要 配对码（从宿主 stderr 读取；是否豁免完全由宿主的 --pairing/--no-pairing 决定）。 完整命令与参数见 docs/web-console/formal-host.md。

控制台里的每个弹框/浮层都能只用键盘操作（F2 模型选择、F5 MCP 面板、F6 目标、 输入框左侧 + 的添加项目、顶栏分支 chip 的 Git Explorer、设置对话框）：打开后焦点 立刻进入框内（模型选择器落在过滤输入框、推理等级落在当前等级，目录 / Git 变更 / MCP 服务器列表落在第一行），↑/↓ 按阅读顺序在框内控件之间移动并首尾相接， Enter/Space 触发聚焦项，Esc 关闭，关闭后焦点回到触发它的那个控件。 回归验收：cd web && node tests/dialogKeyboardNav.verify.ts。

控制台也能作为应用安装（PWA，web/public/manifest.webmanifest）：Chrome 用地址栏 右侧的安装图标，Edge 用「应用 → 安装此站点为应用」，即可得到独立窗口的 Synapse； 任务栏右键另有「新建会话」快捷方式。安装窗口的标题栏由控制台自己的顶栏接管 （display_override: window-controls-overlay，浏览器只保留窗口按钮；不支持该模式的浏览器 退回普通应用窗口）。安装只是外壳——宿主仍然要在跑 （synapse web-console 及其 daemon），页面关掉后不会有后台推送，宿主重启后也要重新配对。 宿主若显式用 --no-pairing，则重启后由下一次会话探测自动重新签发会话（仍非持久化）。 细节与边界见 web/README.md「可安装应用（PWA）」。

Open a session in any registered project from the global catalog:

synapse --session <project_id>:<thread_id>   # global session reference
synapse --project <ref>                      # project by id prefix, name, or path

Inside the TUI, click the topbar ≡ (or the workspace label) to open the floating project drawer: it lists every registered project, groups their sessions, marks live runtime status, and lets you switch sessions in place or jump to another project (the TUI restarts into that project).

Press Ctrl+Tab for a global recent-sessions switcher: it lists the most recently changed sessions across every registered project (from the user-layer catalog), marks each one's live runtime status — running / queued / idle / cold, etc. — lets you Tab / Shift+Tab through them and Enter to switch. The old session keeps running in the background and is never cancelled. Some terminals never forward Ctrl+Tab to the app; Ctrl+O is a drop-in alternative.

/new and switches to cold sessions prepare an independent agent in a background worker, leaving the current session visible until preparation succeeds. While preparing, submitted prompt text stays in the input instead of being sent to the old session; submit it again after the switch. A failed preparation leaves the current session unchanged. Mid-turn steer notifications do not wait for UI repaint, and streaming updates are coalesced into bounded UI batches.

git clone https://github.com/alex8224/synapse-agent.git
cd synapse-agent
uv sync

# Windows venv entry
.\.venv\Scripts\synapse.exe tui -w .

# Or module entry
uv run python -m synapse tui -w .

Use it

Type it like you would ask a colleague:

• "Fix the failing test in tests/test_backends.py"
• "Refactor this module and add type annotations"
• "Review the latest commit and suggest improvements"
• "Keep working on this goal until it is done" (via /goal)

Three ways to talk to it:

Why it is built for long sessions

• Long-running goals — /goal <objective> survives turn boundaries, tracks tokens and elapsed time, and steers the next turn automatically until the goal is completed, paused, blocked, or budget-limited.
• Token-aware tool output — search results, logs, diffs, JSON, and code are classified and compressed before they re-enter the model context; large originals stay recoverable through references.
• Managed long context — automatic summarization and /compact keep sessions inside the model window, with occupancy and savings visible in the TUI.
• Structured system prompt — the prompt is assembled from named, cache-hinted sections whose stable instructions stay byte-identical. AGENT_ENABLE_PROMPT_CACHE_BOUNDARY (off by default) additionally appends the per-build environment, git snapshot, and current date as dynamic context and marks the stable/dynamic seam with a prompt-cache breakpoint, so the volatile tail never invalidates the cached prefix.
• Direct Codex OAuth — sign in with the Codex-compatible browser flow or import an existing Codex grant. No API key required; tokens refresh automatically.
• Your model, your choice — OpenAI-compatible providers via models.json profiles (OpenAI, DeepSeek, local gateways, and more), including a persistent WebSocket mode.
• MCP built in — attach MCP servers and their tools appear in the agent automatically.
• Sessions that resume — SQLite checkpoints, a global project catalog across all your projects, and a lightweight paged transcript so even huge sessions reopen fast.
• Memory and skills — AGENTS.md memory plus Agent Skills (skills/**) that load only when relevant.
• Sub-agents — built-in researcher, tester, and reviewer roles for parallel delegation, plus user-defined subagents from .synapse/agents/*.md.
• Approvals when you want them — optional human-in-the-loop (--require-approval) and safety profiles.

Slash commands

Type /help in the TUI for the full reference. The essentials:

TUI error diagnostics

Turn and approval-resume errors show a nonempty summary (including the exception type when its message is empty) and an Error log: path. Failure diagnostics are enabled by default and written lazily to the turn's own workspace: .synapse/logs/errors-<pid>.log. Each process rotates its file at 1 MiB with three backups. If the file cannot be written, the TUI explicitly reports that instead of hiding the original error.

The JSON-lines log keeps timestamps, operation/session/turn identifiers, exception types, numeric error codes and stack locations. It deliberately omits raw exception messages, source lines, locals, prompts, tool output and settings; the on-screen summary redacts common credential formats. Runtime failures are recorded before conversion to result data, when the traceback is still available. See TUI error details and logs for the PowerShell tail command and retention details. Restart the TUI after updating; earlier unlogged failures cannot be recovered from an ERROR: screenshot.

ACP v1 adapter

The package also installs the standalone synapse-acp stdio entry point. It uses the locked agent-client-protocol==0.12.0 dependency and keeps stdout reserved for ACP JSON-RPC; diagnostics go to stderr.

# Run from an installed package
synapse-acp

# Run from a source checkout
uv run synapse-acp

For a client such as Zed, configure the ACP agent as a subprocess whose command is synapse-acp (or the absolute path to that executable). The adapter accepts absolute cwd values and session-scoped MCP servers. MCP credentials are used only for the live session and are not written to the ACP catalog or transcript.

The published capability set currently covers text prompts, image prompts, permission/HITL, session load/list/close/delete/resume, session-local mode/config, HTTP/SSE MCP configuration, model selection via providers/list/providers/set, and capability-gated Client filesystem/ terminal tools. Thinking level maps directly to Synapse levels (off, minimal, low, medium, high, max). Audio, embedded-context, authentication/logout, elicitation, NES, and document-sync capabilities are not advertised until their runtime semantics and interoperability tests exist.

Troubleshooting:

• stdout is reserved for ACP JSON-RPC; any log line on stdout breaks the protocol. Logs and startup traces go to stderr.
• cwd and additionalDirectories must be absolute paths; relative paths are rejected with an ACP error.
• Session metadata lives in ~/.synapse/acp-sessions.sqlite; MCP credentials and headers are never persisted there.
• If a client reports "Method not found", verify it negotiates the same ACP protocol version and does not rely on not_target methods (auth, providers, elicitation, NES, document sync).

Pick a model

Synapse works with any OpenAI-compatible endpoint. Configure profiles in ~/.synapse/models.json (or <workspace>/.synapse/models.json):

{
  "default": "deepseek",
  "models": {
    "deepseek": {
      "model": "openai:deepseek-v4-pro",
      "api_key": "sk-...",
      "base_url": "http://127.0.0.1:3000/v1",
      "thinking": "high"
    }
  }
}

For a zero-config Codex experience, use the OAuth profile — see Models.

Documentation

The runtime contract (wire method table, event kinds, DTO schemas) is generated from src/synapse/runtime/service/contract_registry.py into src/synapse/runtime/service/contract_manifest.json and web/src/runtime-client/contract.generated.ts. Do not hand-edit either artifact:

uv run --no-sync python scripts/export_contract_manifest.py         # regenerate
uv run --no-sync python scripts/export_contract_manifest.py --check # verify committed output

Repository layout

src/synapse/    Agent assembly, commands, runtime, sessions, TUI, integrations
rust/           Optional native compression cores (PyO3)
docs/           User documentation
tests/          Python test suite
scripts/        Install / release helpers

License

Apache License 2.0 — see LICENSE. Third-party dependencies and Rust subcomponents may carry their own licenses; retain the corresponding license and NOTICE files when distributing.