Jordan Ritter 861e56b90e fix(showcase): LGT remaining delta — 16 test fixes + component extraction + cleanup (#4906)
## Summary
Closes the LGT-vs-LGP delta from PR #4879. Fixes 16 of 17 LGT-only test
failures, extracts inlined components to match LGP's factored pattern,
removes orphan demos, and ports infrastructure.

## Changes

### Test fixes (16 of 17 LGT-only failures)
- **headless-complete**: `normalizeResponse()` for
additional_kwargs.tool_calls + missing `get_revenue_chart` tool
- **readonly-state**: Removed aimock `systemMessage: "Atai"` gate
(gpt-5.4 sends role:developer)
- **reasoning-custom**: Created missing demo page + wired route to
existing reasoning graph
- **reasoning-default**: Renamed from `reasoning-default-render` + added
`suggestions.ts`
- **declarative-gen-ui**: Fixed A2UI tool name (`render_a2ui` →
`_design_a2ui_surface`) + state-aware ToolNode wrapper
- **beautiful-chat**: A2UI v0.9 operation format + ExampleCanvas agentId
+ manage_todos Command + copilotkitEmitState

### Component extraction (inlining → LGP pattern)
- **hitl**: 7 inlined components extracted to separate files
(step-selector, steps-feedback, suggestions, 4 shadcn components)
- **declarative-hashbrown**: All files aligned to LGP
- **declarative-json-render**: All files aligned to LGP
- **shared-state-read**: Extracted recipe-card.tsx + types.ts from
460-line page.tsx
- **reasoning-default**: Extracted suggestions.ts
- **beautiful-chat**: Extracted home-page.tsx

### Cleanup
- Removed `agentic-chat-reasoning` (deprecated, untested, covered by
reasoning-custom)
- Removed `shared-state-write` (unimplemented stub, superseded by
shared-state-read-write)
- Ported `layout.tsx` from LGP (per-demo title metadata)

## Variance after this PR
- Frontend files: 240 identical (96%), 10 justified diffs, 0 functional
gaps
- Tests: 37 identical (100%)
- API routes: 15 identical (100%)

## 1 remaining LGT-only failure
- reasoning-default "Show reasoning pill" — fixture doesn't produce
reasoning tokens for LGT pipeline

## Test plan
- [ ] Full LGP suite on production-parity local cluster
- [ ] Full LGT suite on production-parity local cluster
- [ ] CI checks
2026-05-18 21:02:44 -07:00
2026-05-07 19:08:48 +00:00
2026-04-07 12:29:28 +02:00
2026-05-15 16:14:44 +00:00
2026-05-19 03:56:11 +00:00
2023-06-30 16:46:26 -07:00

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CopilotKit

Build agent-native applications with generative UI, shared state, and human-in-the-loop workflows.

CopilotKit



What is CopilotKit

CopilotKit is a best-in-class SDK for building full-stack agentic applications, Generative UI, and chat applications.

We are the company behind the AG-UI Protocol - adopted by Google, LangChain, AWS, Microsoft, Mastra, PydanticAI, and more!

https://github.com/user-attachments/assets/72b7b4f3-b6e7-460c-a932-5746fe3c8db3

Add AI to your app in 1 minute

Features:

  • Chat UI – A React-based chat interface that supports message streaming, tool calls, and agent responses.
  • Backend Tool Rendering – Enables agents to call backend tools that return UI components rendered directly in the client.
  • Generative UI – Allows agents to generate and update UI components dynamically at runtime based on user intent and agent state.
  • Shared State – A synchronized state layer that both agents and UI components can read from and write to in real time.
  • Human-in-the-Loop – Lets agents pause execution to request user input, confirmation, or edits before continuing.

https://github.com/user-attachments/assets/55bf6714-62a7-4d5d-9232-07747cc0763b

Quick Start

New projects:

npx copilotkit@latest create -f <framework>

Existing projects:

npx copilotkit@latest init

https://github.com/user-attachments/assets/7372b27b-8def-40fb-a11d-1f6585f556ad

What this gives you:

  • CopilotKit installed – Core packages are fully set up in your app
  • Provider configured – Context, state, and hooks ready to use
  • Agent <> UI connected – Agents can stream actions and render UI immediately
  • Deployment-ready – Your app is ready to deploy

Complete getting started guide →

How it works:

CopilotKit connects your UI, agents, and tools into a single interaction loop.

CopilotKit Diagram — Motion x2 6 sec version

This enables:

  • Agents that ask users for input
  • Tools that render UI
  • Stateful workflows across steps and sessions

⭐️ useAgent Hook

The useAgent hook is a proper superset of useCoAgent and sits directly on AG-UI, giving more control over the agent connection.

// Programmatically access and control your agents
const { agent } = useAgent({ agentId: "my_agent" });

// Render and update your agent's state
return <div>
  <h1>{agent.state.city}</h1>
  <button onClick={() => agent.setState({ city: "NYC" })}>
    Set City
  </button>
</div>

Check out the useAgent docs to learn more.

https://github.com/user-attachments/assets/67928406-8abc-49a1-a851-98018b52174f

Generative UI

Generative UI is a core CopilotKit pattern that allows agents to dynamically render UI as part of their workflow.

https://github.com/user-attachments/assets/3cfacac0-4ffd-457a-96f9-d7951e4ab7b6

Compare the Three Types

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Explore:

Generative UI educational repo →

🖥️ AG-UI: The Agent–User Interaction Protocol

Connect agent workflow to user-facing apps, with deep partnerships and 1st-party integrations across the agentic stack—including LangGraph, CrewAI, and more.

AG-UI


npx create-ag-ui-app my-agent-app
Learn more in the AG-UI README →

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📄 License

This repository's source code is available under the MIT License.

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Description
copilotkit-debug: Use when diagnosing CopilotKit issues -- runtime connectivity failures, agent not responding, streaming errors, tool execution problems, transcription…; copilotkit-develop: Use when building AI-powered features with CopilotKit v2 -- adding chat interfaces, registering frontend tools, sharing application context with agents,…; copilotkit-agui: Use when building custom agent backends, implementing the AG-UI protocol, debugging streaming issues, or understanding how agents commun…
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