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WebEngine MCP Plugins for Coding Agents

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WebEngine ships two plugins that turn any compatible coding agent into a browser/device operator: the agent observes the live application through MCP, interacts with it, then generates UI code in your stack (Playwright+TS, Selenium, WebEngine C#).

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PluginProfileToolsSkills
plugins/webengine-web--profile web (Selenium)29webengine-web, webengine-scaffold
plugins/webengine-mobile--profile mobile (Appium)17webengine-mobile, webengine-scaffold
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Both plugins share one server binary (AxaFrance.WebEngine.Mcp, command webengine-mcp) and carry two packaging formats in the same folder: Agent Plugins 1.0 (plugin.json + mcp.json) for VS Code/Copilot, and .codex-plugin/plugin.json + .mcp.json for Codex.

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Prerequisites

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  • .NET 10 (the dnx launcher ships with the SDK) for the zero-install run below.
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  • The package published to NuGet (maintainers: dotnet pack + dotnet nuget push). Before that, use the local-build fallback in each plugin README.
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  • A browser (Chrome/Edge/Firefox) for web; an Appium server (default http://localhost:4723) for mobile.
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Test the server once (no agent needed):

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dnx AxaFrance.WebEngine.Mcp --profile web --transport stdio
+# or, after dotnet tool install -g AxaFrance.WebEngine.Mcp:
+webengine-mcp --help
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GitHub Copilot (VS Code)

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Full plugin (skills + server, recommended):

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  1. Run Chat: Install Plugin From Source and paste https://github.com/AxaFrance/webengine-dotnet, or register the marketplace AxaFrance/webengine-dotnet in chat.plugins.marketplaces, or point chat.pluginLocations at a local clone's plugins/<name> folder.
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  2. Enable the plugin. Its MCP server starts automatically with it.
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  3. Verify: MCP: List Servers shows webengine-web/webengine-mobile; Chat: Configure Skills lists the skills.
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Manual (no plugin install): copy plugins/<name>/skills/* to .github/skills/ and the mcp.json content into .vscode/mcp.json. This repository's own .vscode/mcp.json is a working example (local build).

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Codex (CLI, IDE extension, desktop)

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codex plugin marketplace add AxaFrance/webengine-dotnet --sparse .agents/plugins
+# then install webengine-web / webengine-mobile from the Plugins Directory
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This repository also ships .agents/plugins/marketplace.json for repo-scoped installs. Manual alternative:

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codex mcp add webengine-web -- dnx AxaFrance.WebEngine.Mcp --profile web --transport stdio
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plus copying plugins/<name>/skills/* to ~/.codex/skills/ (restart Codex). Project-scoped MCP goes in .codex/config.toml (trusted projects); see plugins/<name>/config.toml.snippet.

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Claude Code

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Copy plugins/<name>/skills/* to .claude/skills/ (project) or ~/.claude/skills/ (personal), and register the server in claude_desktop_config.json:

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{ "mcpServers": { "webengine-web": {
+  "command": "dnx",
+  "args": ["AxaFrance.WebEngine.Mcp", "--profile", "web", "--transport", "stdio"]
+} } }
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Restart Claude Code and verify the tools list.

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OpenCode

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Skills: copy plugins/<name>/skills/* to .agents/skills/ (project, also picked up by Codex/Cursor) or ~/.config/opencode/skills/. Server in opencode.json:

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{ "$schema": "https://opencode.ai/config.json",
+  "mcp": { "webengine-web": { "type": "local",
+    "command": ["dnx", "AxaFrance.WebEngine.Mcp", "--profile", "web", "--transport", "stdio"],
+    "enabled": true } } }
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(OpenCode v2 nests servers under mcp.servers; check your version's docs.)

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Cursor

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Project skills in .cursor/skills/ (global: ~/.cursor/skills/), server in .cursor/mcp.json using the same stdio command as above.

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Troubleshooting

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  • No tools / garbled handshake: plain dotnet run prints a launch banner to stdout, which breaks MCP stdio. Use dnx, dotnet tool, a published exe, or dotnet exec <dll>.
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  • dnx cannot resolve the package: it is not on NuGet yet — use the local-build fallback from the plugin README.
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  • Mobile session fails: start the Appium server first and check appsettings.json (Appium:DefaultServerUrl).
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  • Both tool sets collide (StartSession twice): never expose both profiles in one process; use --profile web|mobile.
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  • Click intercepted / stale refs: this is page behavior, not an install issue — the skills' references/blockers.md (cookies, modals, SPA re-renders) covers the protocol.
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