diff --git a/.github/workflows/js-tests.yml b/.github/workflows/js-tests.yml
index 4e4622f72d0..50852041b3e 100644
--- a/.github/workflows/js-tests.yml
+++ b/.github/workflows/js-tests.yml
@@ -44,6 +44,17 @@ jobs:
         with:
           node-version: 22
           cache: npm
+      - name: Install uv
+        uses: astral-sh/setup-uv@fac544c07dec837d0ccb6301d7b5580bf5edae39 # 8.2.0
+        with:
+          enable-cache: true
+          cache-dependency-glob: |
+            pyproject.toml
+            uv.lock
+      - name: Install Python development dependencies
+        uses: ./.github/actions/retry
+        with:
+          command: uv sync --locked --extra dev
       - uses: ./.github/actions/retry
         with:
           command: npm ci
diff --git a/.gitignore b/.gitignore
index 29489633104..ad0e5515d81 100644
--- a/.gitignore
+++ b/.gitignore
@@ -90,6 +90,7 @@ apps/desktop/src/**/*.d.ts
 apps/shared/src/**/*.js
 apps/shared/src/**/*.js.map
 apps/shared/src/**/*.d.ts
+apps/shared/src/generated/
 apps/desktop/release/
 *.tsbuildinfo
 
diff --git a/apps/desktop/package.json b/apps/desktop/package.json
index 64312654650..0cd57030a77 100644
--- a/apps/desktop/package.json
+++ b/apps/desktop/package.json
@@ -11,6 +11,7 @@
     "node": "^20.19.0 || >=22.12.0"
   },
   "scripts": {
+    "predev": "npm run generate:gateway-types --prefix ../shared",
     "clean": "npm run clean:e2e && npm run clean:renderer && npm run clean:electron",
     "clean:e2e":"tsc --build tsconfig.e2e.json --clean",
     "clean:renderer":"tsc --build tsconfig.json --clean ",
@@ -23,7 +24,7 @@
     "profile:main": "tsc --build tsconfig.electron.json && wait-on http://127.0.0.1:5174 && node scripts/bundle-electron-main.mjs --dev && cross-env XCURSOR_SIZE=24 HERMES_DESKTOP_DEV_SERVER=http://127.0.0.1:5174 electron --inspect=9229 .",
     "profile:main:cpu": "tsc --build tsconfig.electron.json && wait-on http://127.0.0.1:5174 && node scripts/bundle-electron-main.mjs --dev && cross-env XCURSOR_SIZE=24 NODE_OPTIONS=--cpu-prof HERMES_DESKTOP_DEV_SERVER=http://127.0.0.1:5174 electron .",
     "start": "npm run build && electron .",
-    "prebuild": "npm run clean",
+    "prebuild": "npm run generate:gateway-types --prefix ../shared && npm run clean",
     "build": "node scripts/assert-root-install.mjs && node scripts/write-build-stamp.mjs && vite build && node scripts/bundle-electron-main.mjs && node scripts/stage-native-deps.mjs",
     "postbuild": "node scripts/assert-dist-built.mjs",
     "prebuilder": "node scripts/patch-electron-builder-mac-binary.mjs",
@@ -45,7 +46,7 @@
     "test:desktop:nsis": "node scripts/test-desktop.mjs nsis",
     "test:desktop:existing": "node scripts/test-desktop.mjs existing",
     "test:desktop:fresh": "node scripts/test-desktop.mjs fresh",
-    "typecheck": "tsc -p . --noEmit && tsc -p tsconfig.electron.json --noEmit && tsc -p tsconfig.e2e.json --noEmit",
+    "typecheck": "npm run generate:gateway-types --prefix ../shared && tsc -p . --noEmit && tsc -p tsconfig.electron.json --noEmit && tsc -p tsconfig.e2e.json --noEmit",
     "lint": "eslint src/ electron/",
     "lint:fix": "eslint src/ electron/ --fix",
     "fmt": "prettier --write 'src/**/*.{ts,tsx}' 'electron/**/*.ts' 'vite.config.ts'",
diff --git a/apps/desktop/src/types/hermes.ts b/apps/desktop/src/types/hermes.ts
index a80d6ba8137..707152e0110 100644
--- a/apps/desktop/src/types/hermes.ts
+++ b/apps/desktop/src/types/hermes.ts
@@ -1,3 +1,5 @@
+import type { GatewaySessionRuntimeInfo } from '@hermes/shared/gateway-contracts'
+
 export interface ConfigFieldSchema {
   category?: string
   description?: string
@@ -470,27 +472,7 @@ export interface SessionResumeResponse {
   status?: string
 }
 
-export interface SessionRuntimeInfo {
-  approval_mode?: 'manual' | 'off' | 'smart'
-  branch?: string
-  config_warning?: string
-  credential_warning?: string
-  cwd?: string
-  desktop_contract?: number
-  fast?: boolean
-  install_warning?: string
-  model?: string
-  personality?: string
-  provider?: string
-  reasoning_effort?: string
-  running?: boolean
-  service_tier?: string
-  skills?: Record<string, string[]> | string[]
-  tools?: Record<string, string[]>
-  usage?: Partial<UsageStats>
-  version?: string
-  yolo?: boolean
-}
+export type SessionRuntimeInfo = GatewaySessionRuntimeInfo
 
 export interface UsageStats {
   calls: number
diff --git a/apps/shared/package.json b/apps/shared/package.json
index beb2340f4f7..52a32a77f86 100644
--- a/apps/shared/package.json
+++ b/apps/shared/package.json
@@ -8,14 +8,16 @@
     "./billing": "./src/billing-types.ts",
     "./billing-policy": "./src/billing-policy.ts",
     "./charge-settlement": "./src/charge-settlement.ts",
+    "./gateway-contracts": "./src/generated/gateway.ts",
     "./skin": "./src/skin.ts"
   },
   "types": "./src/index.ts",
   "scripts": {
+    "generate:gateway-types": "uv run --locked --extra dev python ../../scripts/generate_gateway_types.py",
     "lint": "eslint src/",
     "lint:fix": "eslint src/ --fix",
     "fix": "npm run lint:fix",
-    "typecheck": "tsc -p . --noEmit",
+    "typecheck": "npm run generate:gateway-types && tsc -p . --noEmit",
     "check": "npm run typecheck"
   },
   "devDependencies": {
diff --git a/pyproject.toml b/pyproject.toml
index a2a1d6c0ee2..c097751cc87 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -156,7 +156,7 @@ edge-tts = ["edge-tts==7.2.7"]
 modal = ["modal==1.3.4"]
 daytona = ["daytona==0.155.0"]
 hindsight = ["hindsight-client==0.6.1"]
-dev = ["debugpy==1.8.20", "pytest==9.0.2", "pytest-asyncio==1.3.0", "mcp==1.26.0", "starlette==1.0.1", "ty==0.0.21", "ruff==0.15.10", "setuptools==81.0.0"]  # starlette: CVE-2026-48710; setuptools: latest <82 (torch >=2.11 caps setuptools<82)
+dev = ["debugpy==1.8.20", "pytest==9.0.2", "pytest-asyncio==1.3.0", "mcp==1.26.0", "starlette==1.0.1", "ts-type==0.3.4", "ty==0.0.21", "ruff==0.15.10", "setuptools==81.0.0"]  # starlette: CVE-2026-48710; setuptools: latest <82 (torch >=2.11 caps setuptools<82)
 messaging = ["python-telegram-bot[webhooks]==22.6", "discord.py[voice]==2.7.1", "aiohttp==3.14.1", "brotlicffi==1.2.0.1", "slack-bolt==1.29.0", "slack-sdk==3.43.0", "qrcode==7.4.2"]  # aiohttp 3.14.1: CVE-2026-34513/34518/34519/34520/34525 + 34993(RCE)/47265
 cron = []  # croniter is now a core dependency; this extra kept for back-compat
 slack = ["slack-bolt==1.29.0", "slack-sdk==3.43.0", "aiohttp==3.14.1"]
diff --git a/scripts/generate_gateway_types.py b/scripts/generate_gateway_types.py
new file mode 100644
index 00000000000..96cd4920896
--- /dev/null
+++ b/scripts/generate_gateway_types.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+"""Generate TypeScript gateway contracts from ``tui_gateway.contracts``."""
+
+from __future__ import annotations
+
+import os
+from pathlib import Path
+from tempfile import NamedTemporaryFile
+
+import ts_type as ts
+from tui_gateway.contracts import (
+    GatewayMcpServerStatus,
+    GatewayProjectInfo,
+    GatewaySessionRuntimeInfo,
+    GatewayUsage,
+)
+
+ROOT = Path(__file__).resolve().parents[1]
+OUTPUT = ROOT / "apps/shared/src/generated/gateway.ts"
+
+
+def main() -> None:
+    for contract in (
+        GatewayMcpServerStatus,
+        GatewayProjectInfo,
+        GatewayUsage,
+        GatewaySessionRuntimeInfo,
+    ):
+        ts.generator.add(contract, "gateway", contract.__name__)
+
+    source = ts.generator.render()["gateway"]
+    output = "// Generated by scripts/generate_gateway_types.py. Do not edit.\n\n" + source + "\n"
+    OUTPUT.parent.mkdir(parents=True, exist_ok=True)
+
+    # Workspace checks may run concurrently. Replacing an already-complete
+    # temporary file means a typecheck always observes either version, never a
+    # partially-written module.
+    with NamedTemporaryFile("w", encoding="utf-8", dir=OUTPUT.parent, delete=False) as file:
+        file.write(output)
+        temp_path = Path(file.name)
+    os.replace(temp_path, OUTPUT)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tui_gateway/contracts.py b/tui_gateway/contracts.py
new file mode 100644
index 00000000000..b171505e66a
--- /dev/null
+++ b/tui_gateway/contracts.py
@@ -0,0 +1,72 @@
+"""Type-only JSON contracts shared by the TUI gateway and TypeScript clients.
+
+These ``TypedDict`` definitions describe the wire payloads without changing the
+runtime's deliberately lightweight plain-dict serialization.  ``ts-type``
+generates the matching TypeScript definitions during frontend checks.
+"""
+
+from typing import Literal, TypedDict
+
+
+class GatewayMcpServerStatusBase(TypedDict):
+    connected: bool
+    name: str
+    tools: int
+    transport: str
+
+
+class GatewayMcpServerStatus(GatewayMcpServerStatusBase, total=False):
+    disabled: bool
+    status: str
+
+
+class GatewayProjectInfoBase(TypedDict):
+    id: str
+    name: str
+    slug: str
+
+
+class GatewayProjectInfo(GatewayProjectInfoBase, total=False):
+    primary_path: str | None
+
+
+class GatewayUsage(TypedDict, total=False):
+    calls: int
+    context_max: int
+    context_percent: int
+    context_used: int
+    cost_usd: float
+    input: int
+    output: int
+    total: int
+
+
+class GatewaySessionRuntimeInfo(TypedDict, total=False):
+    approval_mode: Literal["manual", "off", "smart"]
+    branch: str
+    config_warning: str
+    credential_warning: str
+    cwd: str
+    desktop_contract: int
+    fast: bool
+    install_warning: str
+    mcp_servers: list[GatewayMcpServerStatus]
+    model: str
+    personality: str
+    profile_name: str
+    project: GatewayProjectInfo | None
+    provider: str
+    reasoning_effort: str
+    release_date: str
+    running: bool
+    service_tier: str
+    skills: dict[str, list[str]] | list[str]
+    stored_session_id: str
+    system_prompt: str
+    title: str
+    tools: dict[str, list[str]]
+    update_behind: int | None
+    update_command: str
+    usage: GatewayUsage
+    version: str
+    yolo: bool
diff --git a/tui_gateway/server.py b/tui_gateway/server.py
index eb9f5cda0e6..3a4564c34a1 100644
--- a/tui_gateway/server.py
+++ b/tui_gateway/server.py
@@ -14,9 +14,10 @@ import sys
 import threading
 import time
 import uuid
+from collections.abc import Mapping
 from datetime import datetime
 from pathlib import Path
-from typing import Any, NamedTuple, Optional
+from typing import Any, NamedTuple, Optional, cast
 
 from hermes_constants import (
     get_hermes_home,
@@ -29,6 +30,7 @@ from utils import is_truthy_value
 from tools.environments.local import hermes_subprocess_env
 from agent.replay_cleanup import sanitize_replay_history
 from tui_gateway import git_probe
+from tui_gateway.contracts import GatewaySessionRuntimeInfo
 from tui_gateway.transport import (
     StdioTransport,
     Transport,
@@ -1212,14 +1214,14 @@ def write_json(obj: dict) -> bool:
     return (current_transport() or _stdio_transport).write(obj)
 
 
-def _event_frame(event: str, sid: str, payload: dict | None = None) -> dict:
+def _event_frame(event: str, sid: str, payload: Mapping[str, Any] | None = None) -> dict:
     params: dict = {"type": event, "session_id": sid}
     if payload is not None:
         params["payload"] = payload
     return {"jsonrpc": "2.0", "method": "event", "params": params}
 
 
-def _emit(event: str, sid: str, payload: dict | None = None):
+def _emit(event: str, sid: str, payload: Mapping[str, Any] | None = None):
     write_json(_event_frame(event, sid, payload))
 
 
@@ -1245,7 +1247,7 @@ def unregister_live_transport(transport: Transport | None) -> None:
         _live_transports.discard(transport)
 
 
-def _broadcast_global_event(event: str, payload: dict | None = None) -> None:
+def _broadcast_global_event(event: str, payload: Mapping[str, Any] | None = None) -> None:
     """Fan a session-less, surface-global event (``skin.changed``) to every
     connected client. Emitters like the skin watcher run on background threads
     where ``write_json``'s ladder bottoms out at stdio and WS peers never see
@@ -4042,7 +4044,7 @@ def _project_info_for_cwd(cwd: str) -> dict | None:
         return None
 
 
-def _session_info(agent, session: dict | None = None) -> dict:
+def _session_info(agent, session: dict | None = None) -> GatewaySessionRuntimeInfo:
     if session is None:
         for candidate in _sessions.values():
             if candidate.get("agent") is agent:
@@ -4161,7 +4163,7 @@ def _session_info(agent, session: dict | None = None) -> dict:
         warn = _probe_credentials(agent)
         if warn:
             info["credential_warning"] = warn
-    return info
+    return cast(GatewaySessionRuntimeInfo, info)
 
 
 def _tool_ctx(name: str, args: dict) -> str:
diff --git a/ui-tui/package.json b/ui-tui/package.json
index 3dbcb758d2c..d2c2eda682d 100644
--- a/ui-tui/package.json
+++ b/ui-tui/package.json
@@ -4,12 +4,13 @@
   "private": true,
   "type": "module",
   "scripts": {
+    "predev": "npm run generate:gateway-types --prefix ../apps/shared",
     "dev": "npm run build:ink && tsx --watch src/entry.tsx",
-    "start": "tsx src/entry.tsx",
-    "build": "node scripts/build.mjs",
+    "start": "npm run generate:gateway-types --prefix ../apps/shared && tsx src/entry.tsx",
+    "build": "npm run generate:gateway-types --prefix ../apps/shared && node scripts/build.mjs",
     "build:ink": "npm run build --prefix packages/hermes-ink",
     "visual": "node scripts/visual/run.mjs",
-    "typecheck": "tsc --noEmit -p tsconfig.json",
+    "typecheck": "npm run generate:gateway-types --prefix ../apps/shared && tsc --noEmit -p tsconfig.json",
     "lint": "eslint src/ packages/",
     "lint:fix": "eslint src/ packages/ --fix",
     "fmt": "prettier --write 'src/**/*.{ts,tsx}' 'packages/**/*.{ts,tsx}'",
diff --git a/ui-tui/src/types.ts b/ui-tui/src/types.ts
index f97506df7c9..0b77bf43d41 100644
--- a/ui-tui/src/types.ts
+++ b/ui-tui/src/types.ts
@@ -1,3 +1,5 @@
+import type { GatewayMcpServerStatus, GatewayProjectInfo } from '@hermes/shared/gateway-contracts'
+
 export interface ActiveTool {
   context?: string
   id: string
@@ -140,21 +142,8 @@ export type ThinkingMode = 'collapsed' | 'truncated' | 'full'
 export type SectionName = 'thinking' | 'tools' | 'subagents' | 'activity'
 export type SectionVisibility = Partial<Record<SectionName, DetailsMode>>
 
-export interface McpServerStatus {
-  connected: boolean
-  disabled?: boolean
-  status?: 'configured' | 'connecting' | 'connected' | 'disabled' | 'failed'
-  name: string
-  tools: number
-  transport: string
-}
-
-export interface ProjectInfo {
-  id: string
-  name: string
-  primary_path?: null | string
-  slug: string
-}
+export type McpServerStatus = GatewayMcpServerStatus
+export type ProjectInfo = GatewayProjectInfo
 
 export interface SessionInfo {
   cwd?: string
diff --git a/uv.lock b/uv.lock
index 3b035b7e277..a33e20236c5 100644
--- a/uv.lock
+++ b/uv.lock
@@ -1597,6 +1597,7 @@ dev = [
     { name = "ruff" },
     { name = "setuptools" },
     { name = "starlette" },
+    { name = "ts-type" },
     { name = "ty" },
 ]
 dingtalk = [
@@ -1847,6 +1848,7 @@ requires-dist = [
     { name = "starlette", marker = "extra == 'web'", specifier = "==1.0.1" },
     { name = "supermemory", marker = "extra == 'supermemory'", specifier = "==3.50.0" },
     { name = "tenacity", specifier = "==9.1.4" },
+    { name = "ts-type", marker = "extra == 'dev'", specifier = "==0.3.4" },
     { name = "ty", marker = "extra == 'dev'", specifier = "==0.0.21" },
     { name = "tzdata", marker = "sys_platform == 'win32'", specifier = "==2025.3" },
     { name = "urllib3", specifier = ">=2.7.0,<3" },
@@ -4136,6 +4138,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/16/e1/3079a9ff9b8e11b846c6ac5c8b5bfb7ff225eee721825310c91b3b50304f/tqdm-4.67.3-py3-none-any.whl", hash = "sha256:ee1e4c0e59148062281c49d80b25b67771a127c85fc9676d3be5f243206826bf", size = 78374, upload-time = "2026-02-03T17:35:50.982Z" },
 ]
 
+[[package]]
+name = "ts-type"
+version = "0.3.4"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/a9/9a/37a2cc86f00818ba15dc2cace832a8bdde4b22fa48c23b2480a10eae8ca6/ts_type-0.3.4.tar.gz", hash = "sha256:5f2e2a4ba4e5f7f63eb7cc5a0208b868dc066da99c34da891bc3cbfe0f27b19d", size = 18003, upload-time = "2025-05-18T05:44:19.288Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/65/be/61270497b881389a61797ea9a288d4560de80d97cfe9679499e2796e5dbb/ts_type-0.3.4-py3-none-any.whl", hash = "sha256:dc16d431d5f8e3e09b923b38f95037c07d95dbed3116964771e65f4cddca7038", size = 14426, upload-time = "2025-05-18T05:44:17.15Z" },
+]
+
 [[package]]
 name = "ty"
 version = "0.0.21"