name: LangGraph (Python)
slug: langgraph-python
category: popular
language: python
logo: /logos/langgraph-python.svg
description: >-
  The most feature-complete CopilotKit integration. LangGraph provides a flexible
  graph-based framework for building agents with Python. Supports the full range of
  CopilotKit features including generative UI, shared state, human-in-the-loop,
  sub-agents, and streaming.
partner_docs: https://docs.copilotkit.ai/integrations/langgraph
repo: https://github.com/CopilotKit/CopilotKit/tree/main/showcase/integrations/langgraph-python
copilotkit_version: 2.0.0
deployed: true
docs_mode: generated
sort_order: 10
generative_ui:
  - constrained-explicit
  - a2ui-fixed-schema
  - a2ui-dynamic-schema
interaction_modalities:
  - sidebar
  - embedded
  - chat
managed_platform:
  name: LangGraph Platform
  url: https://langsmith.com
not_supported_features:
  # QUARANTINED pending a @copilotkit/react-core release. gen-ui-interrupt /
  # interrupt-headless fail turn-2 on a useInterrupt/useHeadlessInterrupt
  # RESUME-PATH hook bug in @copilotkit/react-core/v2: backend resumes + streams
  # (HTTP 200) but the frontend never appends the confirmation assistant bubble,
  # so the harness DOM settle-check times out. Fix is a published-package change
  # (out of scope here); honestly marked not-supported (skipped-incapable, not
  # green, not red) rather than a regression. Demos remain wired below. This is
  # the reference integration, but the bug blocks it too.
  - gen-ui-interrupt
  - interrupt-headless
features:
  - beautiful-chat
  - cli-start
  - agentic-chat
  - prebuilt-sidebar
  - prebuilt-popup
  - chat-slots
  - chat-customization-css
  - headless-simple
  - headless-complete
  - reasoning-custom
  - reasoning-default
  - frontend-tools
  - frontend-tools-async
  - gen-ui-tool-based
  - hitl-in-chat
  - hitl-in-app
  - declarative-gen-ui
  - a2ui-fixed-schema
  - a2ui-recovery
  - mcp-apps
  - gen-ui-agent
  - tool-rendering-default-catchall
  - tool-rendering-custom-catchall
  - tool-rendering
  - tool-rendering-reasoning-chain
  - shared-state-read
  - shared-state-read-write
  - shared-state-streaming
  - readonly-state-agent-context
  - subagents
  - multimodal
  - auth
  - declarative-hashbrown
  - declarative-json-render
  - open-gen-ui
  - open-gen-ui-advanced
  - voice
  - agent-config
a2ui_pattern: schema-loading
interrupt_pattern: native
thread_persistence_pattern: langgraph
agent_config_pattern: shared-state
auth_pattern: langgraph
demos:
  - id: cli-start
    name: CLI Start Command
    description: Copy-paste command to clone the canonical starter
    tags:
      - chat-ui
    command: "npx copilotkit@latest init --framework langgraph-python"
  - id: agentic-chat
    name: "Pre-Built: CopilotChat"
    description: Vanilla CopilotChat with three starter-prompt suggestions — the minimum-viable surface for free-form chat
    tags:
      - chat-ui
    route: /demos/agentic-chat
    animated_preview_url:
    highlight:
      - src/agents/agentic_chat.py
      - src/app/demos/agentic-chat/page.tsx
      - src/app/api/copilotkit/route.ts
  - id: chat-customization-css
    name: "Chat Customization: CSS"
    description: Default CopilotChat re-themed via CopilotKitCSSProperties
    tags:
      - chat-ui
    route: /demos/chat-customization-css
    animated_preview_url:
    highlight:
      - src/agents/main.py
      - src/app/demos/chat-customization-css/page.tsx
      - src/app/demos/chat-customization-css/theme.css
      - src/app/api/copilotkit/route.ts
  - id: tool-rendering-default-catchall
    name: "Generative UI: Tool Rendering (Default)"
    description: Out-of-the-box tool rendering — backend defines the tools; the frontend adds zero custom renderers and relies on CopilotKit's built-in default UI
    tags:
      - generative-ui
    route: /demos/tool-rendering-default-catchall
    animated_preview_url:
    highlight:
      - src/app/demos/tool-rendering-default-catchall/page.tsx
      - src/agents/tool_rendering_agent.py
      - src/app/api/copilotkit/route.ts
  - id: tool-rendering-custom-catchall
    name: "Generative UI: Tool Rendering (Catch-all)"
    description: Single branded wildcard renderer via useDefaultRenderTool — the same app-designed card paints every tool call
    tags:
      - generative-ui
    route: /demos/tool-rendering-custom-catchall
    animated_preview_url:
    highlight:
      - src/app/demos/tool-rendering-custom-catchall/page.tsx
      - src/app/demos/tool-rendering-custom-catchall/custom-catchall-renderer.tsx
      - src/agents/tool_rendering_agent.py
      - src/app/api/copilotkit/route.ts
  - id: frontend-tools
    name: "Frontend Tools: In-app Actions"
    description: Agent invokes client-side handlers registered with useFrontendTool
    tags:
      - interactivity
    route: /demos/frontend-tools
    animated_preview_url:
    highlight:
      - src/agents/frontend_tools.py
      - src/app/demos/frontend-tools/page.tsx
      - src/app/api/copilotkit/route.ts
  - id: frontend-tools-async
    name: "Frontend Tools: Async"
    description: useFrontendTool with an async handler — agent awaits a client-side async operation (simulated notes DB query) and uses the returned result
    tags:
      - interactivity
    route: /demos/frontend-tools-async
    animated_preview_url:
    highlight:
      - src/agents/frontend_tools_async.py
      - src/app/demos/frontend-tools-async/page.tsx
      - src/app/demos/frontend-tools-async/notes-card.tsx
      - src/app/api/copilotkit/route.ts
  - id: hitl-in-chat
    name: "Human In the Loop: In-chat"
    description: Time-slot picker rendered inline in the chat via `useHumanInTheLoop` — the agent requests user input, the frontend renders a TimePickerCard, and the user's choice resumes the agent.
    tags:
      - interactivity
    route: /demos/hitl-in-chat
    animated_preview_url:
    highlight:
      - src/app/demos/hitl-in-chat/page.tsx
      - src/app/demos/hitl-in-chat/time-picker-card.tsx
      - src/agents/hitl_in_chat_agent.py
      - src/app/api/copilotkit/route.ts
  - id: hitl-in-app
    name: "Human in the Loop: In-app"
    description: Agent requests approval via useFrontendTool with an async handler; the approval UI pops up as an app-level modal OUTSIDE the chat, and a completion callback resolves the pending tool Promise with the user's decision
    tags:
      - interactivity
    route: /demos/hitl-in-app
    animated_preview_url:
    highlight:
      - src/agents/hitl_in_app.py
      - src/app/demos/hitl-in-app/page.tsx
      - src/app/demos/hitl-in-app/approval-dialog.tsx
      - src/app/api/copilotkit/route.ts
  - id: tool-rendering
    name: "Generative UI: Tool Rendering (Custom)"
    description: Custom per-tool renderers (WeatherCard, FlightListCard) plus a wildcard catch-all for every other tool
    tags:
      - generative-ui
    route: /demos/tool-rendering
    animated_preview_url:
    highlight:
      - src/agents/tool_rendering_agent.py
      - src/app/demos/tool-rendering/page.tsx
      - src/app/demos/tool-rendering/weather-card.tsx
      - src/app/demos/tool-rendering/flight-list-card.tsx
      - src/app/api/copilotkit/route.ts
  - id: tool-rendering-reasoning-chain
    name: "Generative UI: Tool calls + reasoning"
    description: "Per-tool renderers (WeatherCard, FlightListCard, custom catchall) interleaved with a reasoningMessage slot rendering the agent's reasoning tokens — combines reasoning-display + tool-rendering in one chat surface."
    tags:
      - generative-ui
    route: /demos/tool-rendering-reasoning-chain
    animated_preview_url:
    highlight:
      - src/agents/tool_rendering_reasoning_chain_agent.py
      - src/app/demos/tool-rendering-reasoning-chain/page.tsx
      - src/app/demos/tool-rendering-reasoning-chain/reasoning-block.tsx
      - src/app/demos/tool-rendering-reasoning-chain/weather-card.tsx
      - src/app/demos/tool-rendering-reasoning-chain/flight-list-card.tsx
      - src/app/demos/tool-rendering-reasoning-chain/custom-catchall-renderer.tsx
      - src/app/api/copilotkit/route.ts
  - id: gen-ui-tool-based
    name: "Generative UI: useComponent"
    description: Agent uses tools to trigger UI generation
    tags:
      - controlled-generative-ui
    route: /demos/gen-ui-tool-based
    animated_preview_url:
    highlight:
      - src/agents/gen_ui_tool_based.py
      - src/app/demos/gen-ui-tool-based/page.tsx
      - src/app/demos/gen-ui-tool-based/bar-chart.tsx
      - src/app/api/copilotkit/route.ts
  - id: gen-ui-agent
    name: "Generative UI: Agent State"
    description: "Agent-state-driven Gen UI — the agent plans a live step list via Command(update={steps}); the frontend subscribes through useAgent and renders the steps inside CopilotChat's messageView.children slot."
    tags:
      - generative-ui
    route: /demos/gen-ui-agent
    animated_preview_url:
    highlight:
      - src/agents/gen_ui_agent.py
      - src/app/demos/gen-ui-agent/page.tsx
      - src/app/demos/gen-ui-agent/InlineAgentStateCard.tsx
      - src/app/api/copilotkit/route.ts
  - id: shared-state-streaming
    name: "Shared State: Streaming"
    description: Per-token state delta streaming from agent to UI
    tags:
      - agent-state
    route: /demos/shared-state-streaming
    animated_preview_url:
    highlight:
      - src/agents/shared_state_streaming.py
      - src/app/demos/shared-state-streaming/page.tsx
      - src/app/demos/shared-state-streaming/document-view.tsx
      - src/app/api/copilotkit/route.ts
  - id: shared-state-read-write
    name: "Shared State: Read + Write"
    description: Bidirectional shared state — UI writes preferences via agent.setState; agent writes notes via a Command-returning tool
    tags:
      - agent-state
    route: /demos/shared-state-read-write
    animated_preview_url:
    highlight:
      - src/agents/shared_state_read_write.py
      - src/app/demos/shared-state-read-write/page.tsx
      - src/app/demos/shared-state-read-write/preferences-card.tsx
      - src/app/demos/shared-state-read-write/notes-card.tsx
      - src/app/api/copilotkit/route.ts
  - id: shared-state-read
    name: "Shared State: Read-only"
    description: "Recipe editor publishes form state via agent.setState; the agent reads the recipe context but does not mutate it (no backend tool — neutral default agent)."
    tags:
      - agent-state
    route: /demos/shared-state-read
    animated_preview_url:
    highlight:
      - src/app/demos/shared-state-read/page.tsx
      - src/app/api/copilotkit/route.ts
  - id: subagents
    name: Sub-Agents
    description: Multiple agents with visible task delegation
    tags:
      - multi-agent
    route: /demos/subagents
    animated_preview_url:
    highlight:
      - src/agents/subagents.py
      - src/app/demos/subagents/page.tsx
      - src/app/demos/subagents/delegation-log.tsx
      - src/app/api/copilotkit/route.ts
  - id: prebuilt-sidebar
    name: "Pre-Built: Sidebar"
    description: Docked sidebar chat via <CopilotSidebar />
    tags:
      - chat-ui
    route: /demos/prebuilt-sidebar
    animated_preview_url:
    highlight:
      - src/agents/main.py
      - src/app/demos/prebuilt-sidebar/page.tsx
      - src/app/api/copilotkit/route.ts
  - id: prebuilt-popup
    name: "Pre-Built: Popup"
    description: Floating popup chat via <CopilotPopup />
    tags:
      - chat-ui
    route: /demos/prebuilt-popup
    animated_preview_url:
    highlight:
      - src/agents/main.py
      - src/app/demos/prebuilt-popup/page.tsx
      - src/app/api/copilotkit/route.ts
  - id: chat-slots
    name: "Chat Customization: Slots"
    description: Customize CopilotChat via its slot system
    tags:
      - chat-ui
    route: /demos/chat-slots
    animated_preview_url:
    highlight:
      - src/agents/main.py
      - src/app/demos/chat-slots/page.tsx
      - src/app/demos/chat-slots/slot-wrappers.tsx
      - src/app/api/copilotkit/route.ts
  - id: headless-simple
    name: "Headless UI: Simple"
    description: Minimum viable headless chat — useAgent + useCopilotKit dressed in shadcn/ui primitives. No tool rendering, no generative UI, just text in / text out.
    tags:
      - chat-ui
    route: /demos/headless-simple
    highlight:
      - src/app/demos/headless-simple/page.tsx
      - src/app/demos/headless-simple/chat.tsx
      - src/app/demos/headless-simple/composer.tsx
      - src/app/demos/headless-simple/empty-state.tsx
      - src/app/demos/headless-simple/message-bubble.tsx
  - id: headless-complete
    name: "Headless UI: Complete"
    description: Full headless surface — hand-rolled CopilotChat replacement that wires every render hook (useRenderTool, useDefaultRenderTool, useComponent, useRenderToolCall, useRenderActivityMessage, useSuggestions, useAttachments) on top of shadcn primitives.
    tags:
      - chat-ui
    route: /demos/headless-complete
    highlight:
      - src/app/demos/headless-complete/page.tsx
      - src/app/demos/headless-complete/chat/chat.tsx
      - src/app/demos/headless-complete/hooks/use-tool-renderers.tsx
      - src/app/demos/headless-complete/hooks/use-frontend-components.ts
      - src/app/demos/headless-complete/hooks/use-headless-suggestions.ts
      - src/app/demos/headless-complete/attachments/use-attachments-config.ts
      - src/app/demos/headless-complete/tools/weather-card.tsx
      - src/app/demos/headless-complete/tools/stock-card.tsx
      - src/app/demos/headless-complete/tools/chart-card.tsx
      - src/app/demos/headless-complete/tools/highlight-note.tsx
  - id: reasoning-default
    name: "Reasoning: Default"
    description: Built-in CopilotChatReasoningMessage rendering with no slot override.
    tags:
      - chat-ui
    route: /demos/reasoning-default
    highlight:
      - src/app/demos/reasoning-default/page.tsx
      - src/app/demos/reasoning-default/suggestions.ts
      - src/agents/reasoning_agent.py
  - id: reasoning-custom
    name: "Reasoning: Custom"
    description: Visible reasoning/thinking chain alongside the final answer
    tags:
      - chat-ui
    route: /demos/reasoning-custom
    animated_preview_url:
    highlight:
      - src/app/demos/reasoning-custom/page.tsx
      - src/app/demos/reasoning-custom/reasoning-block.tsx
      - src/agents/reasoning_agent.py
      - src/app/api/copilotkit/route.ts
  - id: gen-ui-interrupt
    name: "Human in the Loop: Interrupts"
    description: Interactive component rendered inline in the chat via the lower-level `useInterrupt` primitive — direct control over the LangGraph interrupt lifecycle
    tags:
      - interactivity
    route: /demos/gen-ui-interrupt
    animated_preview_url:
    highlight:
      - src/agents/interrupt_agent.py
      - src/app/demos/gen-ui-interrupt/page.tsx
      - src/app/demos/gen-ui-interrupt/_components/time-picker-card.tsx
      - src/app/api/copilotkit/route.ts
  - id: interrupt-headless
    name: "Human in the Loop: Headless Interrupts"
    description: "Same interrupt(...) backend pattern as gen-ui-interrupt, but the time-picker mounts in a separate app-surface pane (left) instead of inline inside the chat — uses useHeadlessInterrupt (custom-event subscribe + manual runAgent forwardedProps.command.resume)."
    tags:
      - interactivity
    route: /demos/interrupt-headless
    animated_preview_url:
    highlight:
      - src/agents/interrupt_agent.py
      - src/app/demos/interrupt-headless/page.tsx
      - src/app/api/copilotkit/route.ts
  - id: declarative-gen-ui
    name: "Declarative UI: Dynamic A2UI"
    description: Canonical A2UI BYOC — custom catalog (Card/StatusBadge/Metric/InfoRow/PrimaryButton) wired via a2ui.catalog on the provider
    tags:
      - generative-ui
    route: /demos/declarative-gen-ui
    animated_preview_url:
    highlight:
      - src/agents/a2ui_dynamic.py
      - src/app/demos/declarative-gen-ui/page.tsx
      - src/app/demos/declarative-gen-ui/a2ui/catalog.ts
      - src/app/demos/declarative-gen-ui/a2ui/definitions.ts
      - src/app/demos/declarative-gen-ui/a2ui/renderers.tsx
      - src/app/api/copilotkit/route.ts
  - id: a2ui-fixed-schema
    name: "Declarative UI: Fixed A2UI"
    description: Render an A2UI tree from a fixed, server-side schema — the agent streams data into a pre-authored component tree
    tags:
      - generative-ui
    route: /demos/a2ui-fixed-schema
    animated_preview_url:
    highlight:
      - src/agents/a2ui_fixed.py
      - src/agents/a2ui_schemas/flight_schema.json
      - src/app/demos/a2ui-fixed-schema/page.tsx
      - src/app/demos/a2ui-fixed-schema/a2ui/catalog.ts
      - src/app/demos/a2ui-fixed-schema/a2ui/definitions.ts
      - src/app/demos/a2ui-fixed-schema/a2ui/renderers.tsx
      - src/app/api/copilotkit/route.ts
  - id: a2ui-recovery
    name: A2UI Error Recovery
    description: Makes the A2UI validate->retry recovery loop visible — an invalid first render heals to a valid one, and an always-invalid render shows a graceful recovery-exhausted fallback. Backend-owned via get_a2ui_tools (injectA2UITool=false); reuses the declarative-gen-ui catalog.
    tags:
      - generative-ui
    route: /demos/a2ui-recovery
    animated_preview_url:
    highlight:
      - src/agents/recovery_agent.py
      - src/app/demos/a2ui-recovery/page.tsx
      - src/app/demos/a2ui-recovery/suggestions.ts
      - src/app/api/copilotkit-a2ui-recovery/route.ts
  - id: mcp-apps
    name: MCP Apps
    description: MCP server-driven UI via activity renderers
    tags:
      - generative-ui
    route: /demos/mcp-apps
    animated_preview_url:
    highlight:
      - src/agents/mcp_apps_agent.py
      - src/app/demos/mcp-apps/page.tsx
      - src/app/api/copilotkit-mcp-apps/[[...slug]]/route.ts
  - id: readonly-state-agent-context
    name: "Shared State: Frontend Context"
    description: Frontend provides read-only context to the agent via useAgentContext
    tags:
      - agent-state
    route: /demos/readonly-state-agent-context
    animated_preview_url:
    highlight:
      - src/agents/readonly_state_agent_context.py
      - src/app/demos/readonly-state-agent-context/page.tsx
      - src/app/api/copilotkit/route.ts
  - id: declarative-json-render
    name: "Declarative UI: json-render"
    description: Streaming hierarchical JSON UI spec rendered via @json-render/react, with a Zod-validated catalog (MetricCard + PieChart + BarChart)
    tags:
      - generative-ui
    route: /demos/declarative-json-render
    animated_preview_url:
    highlight:
      - src/agents/byoc_json_render_agent.py
      - src/app/demos/declarative-json-render/page.tsx
      - src/app/demos/declarative-json-render/json-render-renderer.tsx
      - src/app/demos/declarative-json-render/registry.tsx
      - src/app/demos/declarative-json-render/catalog.ts
      - src/app/demos/declarative-json-render/metric-card.tsx
      - src/app/demos/declarative-json-render/charts/bar-chart.tsx
      - src/app/demos/declarative-json-render/charts/pie-chart.tsx
      - src/app/demos/declarative-json-render/types.ts
      - src/app/demos/declarative-json-render/suggestions.ts
      - src/app/api/copilotkit-declarative-json-render/route.ts
  - id: beautiful-chat
    name: Beautiful Chat
    description: Canonical polished starter chat — brand fonts, theme tokens, suggestion pills
    tags:
      - chat-ui
    route: /demos/beautiful-chat
    animated_preview_url:
    highlight:
      - src/agents/beautiful_chat.py
      - src/app/demos/beautiful-chat/page.tsx
      - src/app/demos/beautiful-chat/components/example-layout/index.tsx
      - src/app/demos/beautiful-chat/components/example-canvas/index.tsx
      - src/app/demos/beautiful-chat/components/generative-ui/charts/bar-chart.tsx
      - src/app/demos/beautiful-chat/components/generative-ui/charts/pie-chart.tsx
      - src/app/demos/beautiful-chat/hooks/use-example-suggestions.tsx
      - src/app/demos/beautiful-chat/hooks/use-generative-ui-examples.tsx
      - src/app/api/copilotkit-beautiful-chat/route.ts
  - id: multimodal
    name: Attachments
    description: Image and PDF uploads via CopilotChat attachments, processed by a vision-capable agent
    tags:
      - chat-ui
    route: /demos/multimodal
    animated_preview_url:
    highlight:
      - src/agents/multimodal_agent.py
      - src/app/demos/multimodal/page.tsx
      - src/app/demos/multimodal/sample-attachment-buttons.tsx
      - src/app/api/copilotkit-multimodal/route.ts
  - id: auth
    name: Authentication
    description: Bearer-token gate via runtime onRequest hook with unauthenticated / authenticated states
    tags:
      - platform
    route: /demos/auth
    animated_preview_url:
    highlight:
      - src/app/demos/auth/page.tsx
      - src/app/demos/auth/sign-in-card.tsx
      - src/app/demos/auth/auth-banner.tsx
      - src/app/demos/auth/use-demo-auth.ts
      - src/app/demos/auth/demo-token.ts
      - src/app/api/copilotkit-auth/[[...slug]]/route.ts
  - id: declarative-hashbrown
    name: "Declarative UI: Hashbrown"
    description: Streaming structured output via @hashbrownai/react, rendering a sales dashboard catalog (MetricCard + PieChart + BarChart)
    tags:
      - generative-ui
    route: /demos/declarative-hashbrown
    animated_preview_url:
    highlight:
      - src/agents/byoc_hashbrown_agent.py
      - src/app/demos/declarative-hashbrown/page.tsx
      - src/app/demos/declarative-hashbrown/hashbrown-renderer.tsx
      - src/app/demos/declarative-hashbrown/metric-card.tsx
      - src/app/demos/declarative-hashbrown/charts/bar-chart.tsx
      - src/app/demos/declarative-hashbrown/charts/pie-chart.tsx
      - src/app/demos/declarative-hashbrown/types.ts
      - src/app/demos/declarative-hashbrown/suggestions.ts
      - src/app/api/copilotkit-declarative-hashbrown/route.ts
  - id: open-gen-ui
    name: "Open Generative UI: Default"
    description: "Agent composes UI from a registered component library — distinct from Tool Rendering, which attaches a custom renderer to a *named* backend tool. Use Open Generative UI when you want the agent to assemble UI freely from a palette you control."
    tags:
      - generative-ui
    route: /demos/open-gen-ui
    animated_preview_url:
    highlight:
      - src/agents/open_gen_ui_agent.py
      - src/app/demos/open-gen-ui/page.tsx
      - src/app/api/copilotkit-ogui/route.ts
  - id: open-gen-ui-advanced
    name: "Open Generative UI: Custom"
    description: "Same Open Generative UI surface, with the iframe-rendered components able to call back into frontend sandbox functions (e.g., a Calculator app whose buttons trigger handlers in the host page)."
    tags:
      - generative-ui
    route: /demos/open-gen-ui-advanced
    animated_preview_url:
    highlight:
      - src/agents/open_gen_ui_advanced_agent.py
      - src/app/demos/open-gen-ui-advanced/page.tsx
      - src/app/demos/open-gen-ui-advanced/sandbox-functions.ts
      - src/app/demos/open-gen-ui-advanced/suggestions.ts
      - src/app/api/copilotkit-ogui/route.ts
  - id: voice
    name: Voice
    description: Speech-to-text via @copilotkit/voice with a bundled sample audio button
    tags:
      - chat-ui
    route: /demos/voice
    animated_preview_url:
    highlight:
      - src/agents/main.py
      - src/app/demos/voice/page.tsx
      - src/app/demos/voice/sample-audio-button.tsx
      - src/app/api/copilotkit-voice/[[...slug]]/route.ts
  - id: agent-config
    name: Agent Config Object
    description: Forward a typed config object (tone / expertise / response length) from the provider to the agent's dynamic system prompt
    tags:
      - platform
    route: /demos/agent-config
    animated_preview_url:
    highlight:
      - src/agents/agent_config_agent.py
      - src/app/demos/agent-config/page.tsx
      - src/app/demos/agent-config/config-card.tsx
      - src/app/demos/agent-config/use-agent-config.ts
      - src/app/demos/agent-config/config-types.ts
      - src/app/api/copilotkit-agent-config/route.ts