Angular Signal Forms Migration MCP

What angular-signal-forms-migration-mcp does

The angular-signal-forms-migration-mcp MCP server helps an AI coding agent assess and plan a move from Angular Reactive Forms to Angular Signal Forms. It scans source files for supported Reactive Forms constructs, reports where they occur, and distinguishes changes that are largely mechanical from patterns that need a developer’s decision.

It does not modify files. The agent or developer applies any edits, reviews the resulting diff, and runs the project’s normal checks. It also does not migrate template-driven forms, prove that a migration is fully correct, scan CSS or SCSS, resolve types across files, or reliably inspect template literals containing ${...} substitutions.

How it works

The angular-signal-forms-migration-mcp MCP server exposes six MCP tools:

• find_form_candidates locates Reactive Forms constructs and identifies findings that need human judgment.
• get_signalforms_recipe returns a verified before-and-after recipe for a selected construct.
• analyze_migration_complexity estimates the size of the work and suggests where to begin.
• get_migration_report combines findings and guidance into a Markdown report.
• verify_migration checks for known problems that may compile while remaining semantically incorrect.
• get_angular_upgrade_plan explains how to reach a supported Angular version when the project is below version 21.

Before giving migration advice, it checks that Angular is at least version 21, declared and installed versions agree, and TypeScript uses an exports-aware moduleResolution setting such as bundler, node16, or nodenext. If the project is below version 21, it returns an upgrade plan instead of a migration plan.

Recipes are checked against a real Angular 22 installation and cross-referenced with Angular documentation and the official Angular CLI MCP server. Responses include provenance fields such as the verified version, retrieval time, and sources. Caveats identify unverified guidance and behavior that varies by Angular release.

Setup and configuration

Node.js 20 or newer is required. Run the package with npx; it is a standalone process and should not be installed into the Angular application. A Claude MCP configuration can launch npx -y angular-signal-forms-migration-mcp@latest, and the same command can be placed in another MCP client’s server configuration.

Using @latest causes npx to resolve the package again when the server starts. Without it, a cached version may continue to run. The package checks for updates once per day and writes a short notice to stderr. Set SIGNAL_FORMS_MCP_NO_UPDATE_CHECK to 1 to disable that check. Use --version to inspect the installed package version.

Limitations and notes

Some Reactive Forms patterns have no direct Signal Forms replacement. Complex RxJS chains may require async validation, rxResource, or continued use of RxJS through conversion utilities. Dynamic addControl() and removeControl() operations also have no direct counterpart because the Signal Forms field tree is derived from the model signal’s type.

The angular-signal-forms-migration-mcp MCP server reports known defects rather than proving correctness. Run verify_migration after TypeScript compilation, not instead of it, and read each recipe’s caveats array, especially for version-sensitive APIs.