Module: Phlex::Reactive::MCP

Defined in:
lib/phlex/reactive/mcp.rb,
lib/phlex/reactive/mcp/runner.rb,
lib/phlex/reactive/mcp/server.rb,
lib/phlex/reactive/mcp/base_tool.rb,
lib/phlex/reactive/mcp/tools/find_tool.rb,
lib/phlex/reactive/mcp/tools/config_tool.rb,
lib/phlex/reactive/mcp/tools/doctor_tool.rb,
lib/phlex/reactive/mcp/tools/actions_tool.rb,
lib/phlex/reactive/mcp/tools/components_tool.rb

Overview

The read-only diagnostic MCP server (issue #168): a stdio server exposing five read-only tools (doctor, components, actions, find, config) so Claude Code inside a HOST app can introspect the live reactive registry when debugging. It mirrors pgbus's MCP subtree.

The mcp gem is OPTIONAL and NEVER a gemspec runtime dependency — this whole subtree references the optional gem's constants (MCP::Tool, MCP::Server), so it is kept OUT of the Zeitwerk loader (loader.ignore in lib/phlex/reactive.rb) and loaded explicitly via MCP.load!.

Phlex::Reactive::MCP.load!         # lazy-require the gem + the tool tree
Phlex::Reactive::MCP::Runner.run   # drive the stdio transport

Entry point for a host app: bin/rails phlex_reactive:mcp (a rake task, not an exe — introspection needs the booted Rails app). Consumer .mcp.json:

{ "mcpServers": { "phlex-reactive": {
  "command": "bin/rails", "args": ["phlex_reactive:mcp"] } } }

Defined Under Namespace

Modules: Runner, Server, Tools Classes: BaseTool

Constant Summary collapse

REQUIRES =

Every file under lib/phlex/reactive/mcp/, in DEPENDENCY ORDER (base_tool before the tools that subclass it; the tools before the server that lists them; the server before the runner that builds it). Loaded by load! after the optional gem itself.

%w[
  phlex/reactive/mcp/base_tool
  phlex/reactive/mcp/tools/doctor_tool
  phlex/reactive/mcp/tools/components_tool
  phlex/reactive/mcp/tools/actions_tool
  phlex/reactive/mcp/tools/find_tool
  phlex/reactive/mcp/tools/config_tool
  phlex/reactive/mcp/server
  phlex/reactive/mcp/runner
].freeze

Class Method Summary collapse

Class Method Details

.load! ⇒ Object

Lazy-require the optional mcp gem, then the tool tree in dependency order. Idempotent (plain require). ONLY require "mcp" is rescued — a LoadError from an internal path propagates verbatim so a typo isn't masked as "add the mcp gem".



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# File 'lib/phlex/reactive/mcp.rb', line 45

def load!
  begin
    require "mcp"
  rescue LoadError
    raise Phlex::Reactive::Error,
      "The phlex-reactive MCP diagnostic server needs the `mcp` gem. " \
      "Add `gem \"mcp\"` to your Gemfile (a dev/test group is fine) and run `bundle install`."
  end

  REQUIRES.each { require it }
end