MCP Server + Flutter MCP Toolkit
About
MCP Toolkit for Flutter AI Agent Driven Development (MCP/CLI + custom client side tools) - via closed feedback loop (visual & semantic snapshot) and high client side customization adaptable for any Flutter app. Nowadays it is often called as agentic harness.
Details
- Author
- Arenukvern
- GitHub stars
- 339
- Downloads
- 661
- Categories
- Developer Tools
Jump to
- 30 MCP tools under the fmt_* capability prefix across four categories
- Dynamic Tools Registration for apps to create custom tools at runtime
- Supports inspection, interaction, debug, and lifecycle operations
- Works with multiple AI agents including Claude Code, Codex, and Cursor
- Flutter apps can expose custom MCP tools and resources at runtime
Install the binary via curl, add the toolkit to your Flutter app with flutter-mcp-toolkit codegen-init, install agent skills with flutter-mcp-toolkit init <agent>, then run your app with flutter run --debug.
<div align="center">
flutter-mcp-toolkit
_Inspect and drive a running Flutter app from your AI assistant._
<a title="Discord" href="https://discord.com/invite/y54DpJwmAn" >
</a>
</div>
- 📖 Docs: docs.page/arenukvern/mcp_flutter
- 🤝 Contribute: guide · contributors · code of conduct · security
flutter-mcp-toolkit is a Dart MCP server + Flutter package that lets AI Agents (Codex, Zed, Cursor, Intent, Claude Code, Cline, etc..) take (semantic snapshots, tap widgets, type into forms, hot-reload, and read logs from a Flutter app) or create __its own tools and resources at runtime__ using MCP Toolkit — without leaving the conversation and work with Flutter apps in closed feedback loop - see example of it described in OpenAI Agentic Harness.
The picture's story: the toolkit gives an AI assistant a shared window and control loop into a running Flutter app, so it can inspect state, act like a user, hot reload, read proof, and use custom tools from your app instead of guessing.
> ![NOTICE]: Version 4 is currently a prerelease train. Use 4.0.0-dev.5 only if you are intentionally testing the new architecture; otherwise stay on the latest stable 3.x release until 4.0.0 is promoted.
Get started in 4 steps
# 1. Install the binary
curl -fsSL https://raw.githubusercontent.com/Arenukvern/mcp_flutter/main/install.sh | bash
Installs flutter-mcp-toolkit plus the short fmtk alias for repeated CLI loops.
2. Add the toolkit to your Flutter app
cd my-flutter-app
flutter-mcp-toolkit codegen-init # adds mcp_toolkit + emits main.dart snippet
3. Install skills for your AI agent
flutter-mcp-toolkit init claude-code # or: cursor | codex | cline | agents-skills | all
Alternative (skills only): npx skills add Arenukvern/mcp_flutter -a cursor -y
4. Run
flutter run --debug
That's it. Your AI agent can now inspect and drive the running app — and your app can expose custom MCP tools at runtime (see Dynamic Tools Registration below).
📰 News
- 2026-05-26 — v3.1.0: Platform-view capture routing, macOS/iOS Simulator host screenshots, web CDP tab capture (SCK → CDP → flutter_layer), and cross-platform showcase platform views.
<!-- TODO(arenukvern): add tool to write news automatically -->
Install from marketplaces
| Platform | Command / link |
|----------|----------------|
| Any agent (recommended) | flutter-mcp-toolkit init <agent> — see AI agent setup |
| Claude Code (git catalog) | /plugin marketplace add Arenukvern/mcp_flutter then install flutter-mcp-toolkit |
| Codex (git catalog) | codex plugin marketplace add Arenukvern/mcp_flutter |
| Cursor (local plugin) | flutter-mcp-toolkit init cursor |
| Skills only | npx skills add Arenukvern/mcp_flutter -a <agent> -y (add MCP via init or manual JSON) |
| MCP registries | Smithery, MseeP |
Maintainers submitting to official stores: marketplace submission runbook. Full matrix: marketplace distribution.
Documentation
- Docs for AI Agent and Human - wiki + llms.txt
- Migrating v2 → v3 — fmt_ MCP tools, binaries, client config keys, validate-runtime.
- MCPCallEntry to AgentCallEntry migration — MCPCallEntry removal, AgentCallEntry, platform codegen sync, fmt_migrate_agent_entries.
- IntentCall consumer guide — hosted intentcall_ dependency policy, consumer proof gates, and the boundary between mcp_flutter and upstream IntentCall architecture.
- Why this repo matters — what it is, why it exists.
- CLI vs MCP — pick the right mode.
- Feature map — the 30 tools.
- AI agent setup - for AI Agents.
- Marketplace distribution — Claude, Cursor, Codex, skills.sh.
- Architecture — for contributors.
- Quick Start, Configuration, MCP RPC description
Published packages
| Package | Pub.dev | Role |
|---|---|---|
| mcp_toolkit | 
| Flutter app package for runtime MCP tools/resources and toolkit bootstrap. |
| flutter_mcp_toolkit_core | 
| Pure-Dart shared command/result/capability types. |
| flutter_mcp_toolkit_capability_kernel | 
| Capability kernel contracts for composable MCP units. |
| flutter_mcp_toolkit_capability_core | 
| Server-side fmt_ capability implementation. |
The server binary lives in mcp_server_dart and is shipped through GitHub
Release artifacts as flutter-mcp-toolkit, fmtk, and
flutter-mcp-toolkit-server; it is not a pub.dev package.
Development support
| Need | Start here |
|---|---|
| Contribute code or docs | CONTRIBUTING.md · Contribution guide |
| Add or credit contributors | Contributors guide · .all-contributorsrc |
| Report vulnerabilities | SECURITY.md |
| Validate local changes | steward probe --json --profile quick · make check-contracts |
| Maintain releases | Release train notes · flutter-mcp-toolkit-repo-maintainer |
| Install or update agent skills | AI agent setup · Marketplace distribution |
What it does
The default toolkit surface exposes 30 MCP tools under the fmt_ capability prefix across four categories:
- Inspection — semantic snapshot, view details, errors, screenshots, VM info
- Interaction — tap, scroll, type, fill forms, hot-reload, navigate, wait_for
- Debug — recent logs, evaluate Dart expressions
- Lifecycle — discover apps, hot-reload, hot-restart
See the flutter-mcp-toolkit-{guide,inspect,control,debug} skills for the full
reference (installed by flutter-mcp-toolkit init or npx skills add Arenukvern/mcp_flutter).
Install options: AI agent setup.
Dynamic Tools Registration
Flutter apps can register custom tools and resources at runtime. See how it
works in this short YouTube video.
The same arguments.connection targeting is supported by the CLI's exec,
batch, daemon command/execute, daemon watch/start, and snapshot step args.
> [!NOTE]
> There is official MCP Server for Flutter from Flutter team which exposes Dart tooling.
> The main goal of this project is to bring power of MCP server tools by creating them in Flutter app, using dynamic MCP tools registration and close feedback loop for AI Agent. See how it works in short YouTube video. See Quick Start for more details. See original motivation behind the idea.
⚠️ Note on Dump RPCs
Dump RPC methods (like dump_render_tree) can produce huge token output and
are disabled by default. Enable with --dumps. See
mcp_server_dart README for the full flag surface.
🔒 Security
Generally, since you use MCP server to connect to Flutter app in Debug Mode, it should be safe to use. However, I still recommend to review how it works in ARCHITECTURE.md, how it can be modified to improve security if needed.
This MCP server is verified by MseeP.ai.
🔧 Troubleshooting
1. Connection Issues
- Ensure your Flutter app is running in debug mode
- Verify the port matches in both Flutter app and MCP server
- Check if the port is not being used by another process
- Safest explicit targeting: use arguments.connection.uri and paste exact Flutter machine app.debugPort.wsUri
- If response includes connection_selection_required, retry with arguments.connection.targetId using one URI from availableTargets (or set arguments.connection.uri directly)
2. AI Tool Not Detecting Inspector
- Restart the AI tool after configuration changes
- Verify the configuration JSON syntax
- Check the tool's logs for connection errors
3. Dynamic Tools Not Appearing
- Ensure mcp_toolkit package is properly initialized in your Flutter app
- Check that tools are registered using MCPToolkitBinding.instance.addEntries()
- Use fmt_list_client_tools_and_resources to verify registration
- Hot reload your Flutter app after adding new tools
The Flutter MCP Server is registered with Smithery's registry, making it discoverable and usable by other AI tools through a standardized interface.
Integration Architecture
┌─────────────────┐ ┌───────────────────────┐ ┌─────────────────┐
│ │ │ Flutter App with │ │ │
│ Flutter App │<--->│ mcp_toolkit │<--->│ flutter-mcp- │
│ (Debug Mode) │ │ (VM Svc. Extensions │ │ toolkit-server │
│ │ │ + Dynamic Tools) │ │ │
└─────────────────┘ └───────────────────────┘ └─────────────────┘
🤝 Contributing
Contributions are welcome! See CONTRIBUTING.md (maintainer releases, binary checksums) and the contribution guide. Pull requests and issues: GitHub.
✨ Contributors
Huge thanks to all contributors for making this project better!
This roster is maintained with all-contributors.
To add someone, update .all-contributorsrc and
regenerate the README table, or use the all-contributors bot/CLI from a PR.
More detail: docs/contributing/contributors.mdx.
<!-- https://allcontributors.org/docs/en/bot/usage -->
<!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
<!-- prettier-ignore-start -->
<!-- markdownlint-disable -->
<table>
<tbody>
<tr>
<td align="center" valign="top" width="14.28%"><a href="https://calclavia.com">
<td align="center" valign="top" width="14.28%"><a href="https://github.com/marwenbk">
<td align="center" valign="top" width="14.28%"><a href="http://eastagile.com">
<td align="center" valign="top" width="14.28%"><a href="https://glama.ai">
<td align="center" valign="top" width="14.28%"><a href="https://github.com/Harishwarrior">
<td align="center" valign="top" width="14.28%"><a href="https://github.com/torbenkeller">
<td align="center" valign="top" width="14.28%"><a href="https://github.com/rednikisfun">
</tr>
<tr>
<td align="center" valign="top" width="14.28%"><a href="https://github.com/cosystudio">
<td align="center" valign="top" width="14.28%"><a href="https://github.com/lukemmtt">
<td align="center" valign="top" width="14.28%"><a href="https://commentatk-media.com">
<td align="center" valign="top" width="14.28%"><a href="https://www.linkedin.com/in/umitarslan/">
<td align="center" valign="top" width="14.28%"><a href="https://joelkitching.com/">
<td align="center" valign="top" width="14.28%"><a href="https://github.com/jeanlucthumm">
<td align="center" valign="top" width="14.28%"><a href="https://github.com/tekboxs">
</tr>
<tr>
<td align="center" valign="top" width="14.28%"><a href="https://github.com/drown0315">
<td align="center" valign="top" width="14.28%"><a href="https://github.com/druyang">
</tr>
</tbody>
</table>
<!-- markdownlint-restore -->
<!-- prettier-ignore-end -->
<!-- ALL-CONTRIBUTORS-LIST:END -->
📖 Learn More
- Flutter DevTools Documentation
- Dart VM Service Protocol
- Flutter DevTools RPC Constants (I guess and hope they are correct:))
Star History
<a href="https://www.star-history.com/?type=date&repos=Arenukvern%2Fmcp_flutter">
<picture>
<source media="(prefers-color-scheme: dark)" srcset="https://api.star-history.com/chart?repos=Arenukvern/mcp_flutter&type=date&theme=dark&legend=top-left" />
<source media="(prefers-color-scheme: light)" srcset="https://api.star-history.com/chart?repos=Arenukvern/mcp_flutter&type=date&legend=top-left" />
</picture>
</a>
📄 License
MIT - Feel free to use in your projects!
---
_Flutter and Dart are trademarks of Google LLC._
Sign in to leave a review
Use Google, GitHub, or an email account so ratings stay tied to real people.
No reviews posted yet.
