Module: Legion::MCP::Server

Defined in:
lib/legion/mcp/server.rb

Constant Summary collapse

MCP_SPECIFIC_TOOLS =

MCP-specific tools not owned by any extension. All extension-owned tools are discovered via Legion::Tools::Registry.

[
  Tools::PlanAction,
  Tools::DiscoverTools,
  Tools::StructuralIndexTool,
  Tools::ToolAudit,
  Tools::StateDiff,
  Tools::SearchSessions,
  Tools::SkillList,
  Tools::SkillDescribe,
  Tools::SkillInvoke,
  Tools::SkillCancel
].freeze

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.tool_registry ⇒ Object (readonly)

Returns the value of attribute tool_registry.



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# File 'lib/legion/mcp/server.rb', line 45

def tool_registry
  @tool_registry
end

Class Method Details

.build(identity: nil) ⇒ Object

rubocop:disable Metrics/MethodLength



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# File 'lib/legion/mcp/server.rb', line 96

def build(identity: nil) # rubocop:disable Metrics/MethodLength
  run_function_discovery
  rebuild_tool_registry

  LoggingSupport.info(
    'server.build.start',
    identity:      LoggingSupport.summarize_identity(identity),
    registry_size: tool_registry.size,
    governance:    ToolGovernance.governance_enabled?
  )
  tools = if ToolGovernance.governance_enabled?
            ToolGovernance.filter_tools(tool_registry, identity)
          else
            tool_registry
          end

  server = ::MCP::Server.new(
    name:               'legion',
    version:            defined?(Legion::VERSION) ? Legion::VERSION : Legion::MCP::VERSION,
    instructions:       instructions,
    tools:              tools,
    resources:          Resources::ExtensionInfo.static_resources,
    resource_templates: Resources::ExtensionInfo.resource_templates
  )

  if defined?(Observer)
    ::MCP.configure do |c|
      c.instrumentation_callback = ->(idata) { Server.wire_observer(idata) }
    end
  end

  install_deferred_tools_list_handler(server)

  PatternStore.hydrate_from_l2 if defined?(PatternStore)
  ColdStart.load_community_patterns if defined?(ColdStart)
  populate_embedding_index

  Resources::RunnerCatalog.register(server)
  Resources::ExtensionInfo.register_read_handler(server)

  hydrate_override_confidence

  LoggingSupport.info(
    'server.build.complete',
    identity:       LoggingSupport.summarize_identity(identity),
    tool_count:     tools.size,
    registry_size:  tool_registry.size,
    resource_count: server.resources.size
  )
  server
end

.build_filtered_tool_list(keywords: []) ⇒ Object 



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# File 'lib/legion/mcp/server.rb', line 201

def build_filtered_tool_list(keywords: [])
  tool_names = tool_registry.map { |tc| tc.respond_to?(:tool_name) ? tc.tool_name : tc.name }
  ranked     = UsageFilter.ranked_tools(tool_names, keywords: keywords)
  ranked.filter_map do |name|
    tool_registry.find do |tc|
      (tc.respond_to?(:tool_name) ? tc.tool_name : tc.name) == name
    end
  end
end

.populate_embedding_index(embedder: EmbeddingIndex.default_embedder) ⇒ Object 



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# File 'lib/legion/mcp/server.rb', line 148

def populate_embedding_index(embedder: EmbeddingIndex.default_embedder)
  return unless embedder

  tool_data = ContextCompiler.tool_index.values
  EmbeddingIndex.build_from_tool_data(tool_data, embedder: embedder)
  LoggingSupport.info(
    'server.embedding_index.populated',
    tool_count: tool_data.size
  )
end

.rebuild_tool_registry ⇒ Object 



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# File 'lib/legion/mcp/server.rb', line 47

def rebuild_tool_registry
  @tool_registry_lock.synchronize do
    @tool_registry = Concurrent::Array.new(MCP_SPECIFIC_TOOLS)

    if defined?(Legion::Tools::Registry) && Legion::Tools::Registry.respond_to?(:all_tools)
      Legion::Tools::Registry.all_tools.each do |legion_tool_class|
        next if @tool_registry.any? { |tc| tc.tool_name == legion_tool_class.tool_name }

        adapted = ToolAdapter.from_legion_tool(legion_tool_class)
        @tool_registry << adapted
      end
    end

    DeferredRegistry.reset_cache! if defined?(DeferredRegistry) && DeferredRegistry.respond_to?(:reset_cache!)
    reset_caches!
  end
end

.register_tool(tool_class) ⇒ Object 



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# File 'lib/legion/mcp/server.rb', line 65

def register_tool(tool_class)
  @tool_registry_lock.synchronize do
    return if tool_registry.any? { |tc| tc.tool_name == tool_class.tool_name }

    tool_registry << tool_class
    reset_caches!
    LoggingSupport.info(
      'server.tool.registered',
      tool_name:     tool_class.tool_name,
      registry_size: tool_registry.size
    )
  end
end

.reset_caches! ⇒ Object 



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# File 'lib/legion/mcp/server.rb', line 91

def reset_caches!
  ContextCompiler.reset! if defined?(ContextCompiler)
  EmbeddingIndex.reset! if defined?(EmbeddingIndex) && EmbeddingIndex.respond_to?(:reset!)
end

.unregister_tool(tool_name) ⇒ Object 



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# File 'lib/legion/mcp/server.rb', line 79

def unregister_tool(tool_name)
  @tool_registry_lock.synchronize do
    tool_registry.reject! { |tc| tc.tool_name == tool_name }
    reset_caches!
    LoggingSupport.info(
      'server.tool.unregistered',
      tool_name:     tool_name,
      registry_size: tool_registry.size
    )
  end
end

.wire_observer(data) ⇒ Object 



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# File 'lib/legion/mcp/server.rb', line 159

def wire_observer(data)
  return unless data[:method] == 'tools/call' && data[:tool_name]

  duration_ms = (data[:duration].to_f * 1000).to_i
  params_keys = data[:tool_arguments].respond_to?(:keys) ? data[:tool_arguments].keys : []
  success     = data[:error].nil?
  request_id  = LoggingSupport.request_id_from(data[:tool_arguments])

  LoggingSupport.info(
    'server.tool_call.complete',
    request_id:  request_id,
    tool_name:   data[:tool_name],
    success:     success,
    duration_ms: duration_ms,
    params_keys: params_keys,
    error:       data[:error]
  )

  Observer.record(
    tool_name:   data[:tool_name],
    duration_ms: duration_ms,
    success:     success,
    params_keys: params_keys,
    error:       data[:error]
  )

  # Pattern promotion for legion.do is handled inside DoAction itself
  # (which knows the actual resolved tool name). For other tools called
  # directly, we record the intent+result here if an intent is present.
  return if data[:tool_name] == 'legion.do'
  return unless data[:tool_arguments]&.dig(:intent)

  observer_args = {
    intent:    data[:tool_arguments][:intent],
    tool_name: data[:tool_name],
    success:   success
  }
  observer_args[:request_id] = request_id if request_id

  Observer.record_intent_with_result(**observer_args)
end