diff --git a/actionagent/app/controllers/action_agent/api/mcp_controller.rb b/actionagent/app/controllers/action_agent/api/mcp_controller.rb
index bf6fe447..f5a56b9c 100644
--- a/actionagent/app/controllers/action_agent/api/mcp_controller.rb
+++ b/actionagent/app/controllers/action_agent/api/mcp_controller.rb
@@ -19,7 +19,7 @@ module Api
     # Connect from an MCP client with:
     #   { "type": "http", "url": "https://activeagents.ai/mcp",
     #     "headers": { "Authorization": "Bearer aa_..." } }
-    class McpController < BaseController
+    class MCPController < BaseController
       # Authenticated by API key rather than by the host app's sessions.
       allow_unauthenticated_access
       before_action :authenticate_api_key!
@@ -51,7 +51,7 @@ def create
       rescue McpError => e
         render_error(request_id, e.code, e.message)
       rescue StandardError => e
-        Rails.logger.error("[Api::McpController] #{e.class}: #{e.message}")
+        Rails.logger.error("[Api::MCPController] #{e.class}: #{e.message}")
         render_error(request_id, JSONRPC_SERVER_ERROR, "Internal error")
       end
 
diff --git a/actionagent/app/controllers/action_agent/api/mcp_servers_controller.rb b/actionagent/app/controllers/action_agent/api/mcp_servers_controller.rb
index a2d64a46..d47cda91 100644
--- a/actionagent/app/controllers/action_agent/api/mcp_servers_controller.rb
+++ b/actionagent/app/controllers/action_agent/api/mcp_servers_controller.rb
@@ -7,9 +7,9 @@ module Api
     #
     # The list is the union of three things: servers detected from telemetry
     # and solid_agent records (ToolDiscovery), servers an agent declares in
-    # its configuration, and the default catalog (McpCatalog). An install
+    # its configuration, and the default catalog (MCPCatalog). An install
     # therefore sees both what it is already using and what it could turn on.
-    class McpServersController < BaseController
+    class MCPServersController < BaseController
       before_action :require_owner!
       # Launching provisions a sandbox and runs a server in it, so it answers
       # to the same two gates as any other execution: the read-only kill
@@ -33,7 +33,7 @@ def index
 
         render json: {
           servers: servers,
-          catalog: McpCatalog.all,
+          catalog: MCPCatalog.all,
           summary: summary_for(servers),
           sandboxes: active_sandboxes,
           window_hours: finder.window_hours,
@@ -111,7 +111,7 @@ def assign_owner(sandbox, association, record)
       end
 
       def set_catalog_entry
-        @catalog_entry = McpCatalog.find(params[:id])
+        @catalog_entry = MCPCatalog.find(params[:id])
         render json: { error: "Unknown MCP server: #{params[:id]}" }, status: :not_found if @catalog_entry.nil?
       end
 
diff --git a/actionagent/app/models/action_agent/sandbox_session.rb b/actionagent/app/models/action_agent/sandbox_session.rb
index 3f706439..59f8e3e7 100644
--- a/actionagent/app/models/action_agent/sandbox_session.rb
+++ b/actionagent/app/models/action_agent/sandbox_session.rb
@@ -48,7 +48,7 @@ class SandboxSession < ApplicationRecord
     # Unknown keys are dropped rather than raising — a session outlives a
     # catalog edit.
     def mcp_catalog_entries
-      Array(mcp_servers).filter_map { |key| McpCatalog.find(key) }
+      Array(mcp_servers).filter_map { |key| MCPCatalog.find(key) }
     end
 
     # Check if session is still valid
diff --git a/actionagent/app/services/action_agent/agent_toolbox.rb b/actionagent/app/services/action_agent/agent_toolbox.rb
index 38e073e3..aa0fdb4d 100644
--- a/actionagent/app/services/action_agent/agent_toolbox.rb
+++ b/actionagent/app/services/action_agent/agent_toolbox.rb
@@ -46,7 +46,7 @@ class AgentToolbox
           }
         }
       ],
-      # A real browser via a Playwright MCP server (PlaywrightMcpClient).
+      # A real browser via a Playwright MCP server (PlaywrightMCPClient).
       # Stateful: navigate changes what snapshot/click see, so these bypass
       # the toolbox result cache.
       "playwright_mcp" => [
@@ -288,17 +288,17 @@ def browser_click(ref:, element: nil)
       SNAPSHOT_LINK = /\[Snapshot\]\(([^)]+)\)/
 
       def playwright_mcp(tool, arguments, retried: false)
-        result = PlaywrightMcpClient.instance.call_tool(tool, arguments)
+        result = PlaywrightMCPClient.instance.call_tool(tool, arguments)
         text = inline_snapshot(result[:text].to_s)
         if text.length > PLAYWRIGHT_RESULT_LIMIT
           text = "#{text[0, PLAYWRIGHT_RESULT_LIMIT]}\n…(truncated, #{text.length} chars total)"
         end
         result[:is_error] ? { error: text.presence || "browser tool failed" } : { text: text }
-      rescue PlaywrightMcpClient::Error => e
+      rescue PlaywrightMCPClient::Error => e
         # One fresh-session retry: the first call after a server (re)start can
         # race the browser launch.
         unless retried
-          PlaywrightMcpClient.reset!
+          PlaywrightMCPClient.reset!
           return playwright_mcp(tool, arguments, retried: true)
         end
         { error: e.message }
diff --git a/actionagent/app/services/action_agent/mcp_catalog.rb b/actionagent/app/services/action_agent/mcp_catalog.rb
index 0f1a8c7e..0efbc1e0 100644
--- a/actionagent/app/services/action_agent/mcp_catalog.rb
+++ b/actionagent/app/services/action_agent/mcp_catalog.rb
@@ -19,7 +19,7 @@ module ActionAgent
   # shows up in the MCP Services view (as +known: false+) the moment a
   # namespaced tool call from it is ingested. The catalog only adds names,
   # descriptions, and the ability to launch.
-  class McpCatalog
+  class MCPCatalog
     # Whether a server can be started inside a sandbox session. Servers that
     # need workspace-specific credentials (github, slack, postgres) are
     # listable and attributable but not launchable from the dashboard — there
diff --git a/actionagent/app/services/action_agent/mcp_recording_middleware.rb b/actionagent/app/services/action_agent/mcp_recording_middleware.rb
index 553a4b0f..536dfba6 100644
--- a/actionagent/app/services/action_agent/mcp_recording_middleware.rb
+++ b/actionagent/app/services/action_agent/mcp_recording_middleware.rb
@@ -7,7 +7,7 @@ module ActionAgent
   # to a SessionRecording for playback and debugging.
   #
   # Usage:
-  #   middleware = McpRecordingMiddleware.new(session_recording: recording)
+  #   middleware = MCPRecordingMiddleware.new(session_recording: recording)
   #
   #   # Process a tool call
   #   result = middleware.intercept(tool_call) do
@@ -15,7 +15,7 @@ module ActionAgent
   #     mcp_client.call_tool(tool_call)
   #   end
   #
-  class McpRecordingMiddleware
+  class MCPRecordingMiddleware
     # Map of Playwright MCP tool names to our action types
     PLAYWRIGHT_TOOLS = {
       "browser_navigate" => "navigate",
diff --git a/actionagent/app/services/action_agent/playwright_mcp_client.rb b/actionagent/app/services/action_agent/playwright_mcp_client.rb
index d35af643..d33fc530 100644
--- a/actionagent/app/services/action_agent/playwright_mcp_client.rb
+++ b/actionagent/app/services/action_agent/playwright_mcp_client.rb
@@ -9,7 +9,7 @@ module ActionAgent
   # app in development, or a sandbox-provisioned browser container in
   # production. Speaks just enough JSON-RPC for tools/call: initialize once
   # per process, then call tools under the session id the server hands back.
-  class PlaywrightMcpClient
+  class PlaywrightMCPClient
     DEFAULT_URL = ENV.fetch("PLAYWRIGHT_MCP_URL", "http://host.orb.internal:8931/mcp")
     OPEN_TIMEOUT_SECONDS = 5
     READ_TIMEOUT_SECONDS = 60
@@ -31,7 +31,7 @@ def initialize(url: DEFAULT_URL)
 
     # Returns { text:, is_error: } — the tool result's text content.
     def call_tool(name, arguments = {})
-      Rails.logger.debug("[PlaywrightMcpClient] call #{name} args=#{arguments.inspect[0, 200]}")
+      Rails.logger.debug("[PlaywrightMCPClient] call #{name} args=#{arguments.inspect[0, 200]}")
       ensure_session!
       response = post(
         { jsonrpc: "2.0", id: next_id, method: "tools/call",
@@ -40,7 +40,7 @@ def call_tool(name, arguments = {})
       )
       result = response["result"]
       unless result
-        Rails.logger.warn("[PlaywrightMcpClient] #{name} unexpected response: #{response.inspect[0, 500]}")
+        Rails.logger.warn("[PlaywrightMCPClient] #{name} unexpected response: #{response.inspect[0, 500]}")
         raise Error, (response.dig("error", "message") || "empty MCP response")
       end
 
@@ -100,17 +100,17 @@ def blocking_post_raw(payload, session: nil)
 
       response = http.request(request)
       Rails.logger.debug(
-        "[PlaywrightMcpClient] #{payload[:method]} -> #{response.code} " \
+        "[PlaywrightMCPClient] #{payload[:method]} -> #{response.code} " \
         "ct=#{response['Content-Type']} bytes=#{response.body.to_s.bytesize} session=#{session ? 'yes' : 'no'}"
       )
       unless response.code.to_i.between?(200, 299)
-        Rails.logger.warn("[PlaywrightMcpClient] HTTP #{response.code}: #{response.body.to_s[0, 300]}")
+        Rails.logger.warn("[PlaywrightMCPClient] HTTP #{response.code}: #{response.body.to_s[0, 300]}")
         raise Error, "MCP server returned HTTP #{response.code}"
       end
 
       parsed = parse_body(response)
       if parsed.empty? && payload[:id]
-        Rails.logger.warn("[PlaywrightMcpClient] unparsed body (#{response['Content-Type']}): #{response.body.to_s[0, 500]}")
+        Rails.logger.warn("[PlaywrightMCPClient] unparsed body (#{response['Content-Type']}): #{response.body.to_s[0, 500]}")
       end
       [ parsed, response ]
     end
diff --git a/actionagent/app/services/action_agent/tool_discovery.rb b/actionagent/app/services/action_agent/tool_discovery.rb
index 924bd634..e62e8fc3 100644
--- a/actionagent/app/services/action_agent/tool_discovery.rb
+++ b/actionagent/app/services/action_agent/tool_discovery.rb
@@ -30,7 +30,7 @@ module ActionAgent
   #
   # MCP attribution comes from ActiveAgent::Telemetry::ToolOrigin (the
   # +mcp__server__tool+ convention, tagged onto spans at instrumentation
-  # time), then McpCatalog's hints for bare tool names, then the tool is
+  # time), then MCPCatalog's hints for bare tool names, then the tool is
   # treated as a method the agent class defines.
   #
   # Scopes are passed in rather than derived, so the caller's ownership
@@ -404,7 +404,7 @@ def classify(name)
       classification = ActiveAgent::Telemetry::ToolOrigin.classify(name)
       return { origin: ORIGIN_MCP, server: classification[:server] } if classification[:server].present?
 
-      if (hinted = McpCatalog.server_for_tool(name))
+      if (hinted = MCPCatalog.server_for_tool(name))
         # A catalog hint is weaker evidence than a namespaced name: the tool
         # is *probably* this server's, but a builtin of the same name is the
         # dashboard's own implementation, so builtins win the tie.
@@ -474,7 +474,7 @@ def base_name(name)
 
     def source_label(origin, server)
       case origin
-      when ORIGIN_MCP then server.present? ? "MCP · #{McpCatalog.display_name(server)}" : "MCP"
+      when ORIGIN_MCP then server.present? ? "MCP · #{MCPCatalog.display_name(server)}" : "MCP"
       when ORIGIN_BUILTIN then "Dashboard toolbox"
       else "Agent-defined"
       end
@@ -500,7 +500,7 @@ def servers_for(tools)
         end
       end
 
-      keys = (McpCatalog::BY_KEY.keys + detected.keys + configured_servers.keys).uniq
+      keys = (MCPCatalog::BY_KEY.keys + detected.keys + configured_servers.keys).uniq
 
       # detected has a default block that would materialize a bucket on
       # lookup, so unseen servers are passed through as an explicit nil.
@@ -509,7 +509,7 @@ def servers_for(tools)
     end
 
     def server_row(key, bucket)
-      catalog = McpCatalog.find(key)
+      catalog = MCPCatalog.find(key)
       configured = configured_servers[key].to_a.sort
       calls = bucket ? bucket[:calls] : 0
 
diff --git a/actionagent/config/routes.rb b/actionagent/config/routes.rb
index bb720bc2..4c42e059 100644
--- a/actionagent/config/routes.rb
+++ b/actionagent/config/routes.rb
@@ -70,7 +70,7 @@
     resources :tools, only: [ :index ]
 
     # MCP services — detected servers unioned with the default catalog
-    # (McpCatalog), plus on-demand sandbox provisioning. Keys are catalog
+    # (MCPCatalog), plus on-demand sandbox provisioning. Keys are catalog
     # slugs like "sequential-thinking", so the id segment allows dashes.
     resources :mcp_servers, only: [ :index, :show ], id: /[^\/]+/ do
       member do
diff --git a/actionagent/lib/action_agent/engine.rb b/actionagent/lib/action_agent/engine.rb
index 2857c068..47f0c4b2 100644
--- a/actionagent/lib/action_agent/engine.rb
+++ b/actionagent/lib/action_agent/engine.rb
@@ -14,11 +14,25 @@ class Engine < ::Rails::Engine
     engine_name "action_agent"
 
     # Basenames this engine spells differently from Zeitwerk's default
-    # camelization, consulted by the inflections initializer below. Empty
-    # today: every file here is named for the constant default camelization
-    # produces. An engine file that wants a genuine acronym in its constant
-    # adds its basename here rather than relying on the host to register one.
-    INFLECTION_OVERRIDES = {}.freeze
+    # camelization, consulted by the inflections initializer below. An engine
+    # file that wants a genuine acronym in its constant adds its basename here
+    # rather than relying on the host to register one.
+    INFLECTION_OVERRIDES = {
+      "mcp_catalog" => "MCPCatalog",
+      "mcp_controller" => "MCPController",
+      "mcp_recording_middleware" => "MCPRecordingMiddleware",
+      "mcp_servers_controller" => "MCPServersController",
+      "playwright_mcp_client" => "PlaywrightMCPClient"
+    }.freeze
+
+    # The spelling default camelization produces for each overridden file,
+    # mapped to the constant the file actually defines. The const_missing shim
+    # below uses it to answer lookups that camelized with default inflections
+    # (a plain host's router, or caller code written against the pre-acronym
+    # names) with the acronym constant.
+    DEFAULT_SPELLINGS = INFLECTION_OVERRIDES.to_h { |basename, constant|
+      [ Zeitwerk::Inflector.new.camelize(basename, nil), constant ]
+    }.freeze
 
     config.action_agent = ActiveSupport::OrderedOptions.new
 
@@ -34,14 +48,13 @@ class Engine < ::Rails::Engine
     end
 
     # This engine's constants are spelled the way Zeitwerk's own inflector
-    # spells them — Api, McpCatalog, ApiKey — but an engine's files are
+    # spells them — Api, ApiKey — but an engine's files are
     # autoloaded by the host's `rails.main` loader, under the *host's*
     # inflections. A host that declares `inflect.acronym "API"` or "MCP" (both
     # common, and documented by Rails) makes Zeitwerk expect
-    # ActionAgent::API::TracesController or ActionAgent::MCPCatalog from files
-    # that define ActionAgent::Api::TracesController and
-    # ActionAgent::McpCatalog. The constant never resolves and the request
-    # raises Zeitwerk::NameError.
+    # ActionAgent::API::TracesController from a file
+    # that defines ActionAgent::Api::TracesController. The constant never
+    # resolves and the request raises Zeitwerk::NameError.
     #
     # Every path under this engine therefore camelizes with Zeitwerk's default
     # rules, ignoring whatever acronyms the host has registered. Applied by
@@ -51,7 +64,8 @@ class Engine < ::Rails::Engine
     # engine's files from the host's.
     #
     # Basenames whose spelling this engine cannot express through default
-    # camelization (a genuine acronym it wants uppercased) go in OVERRIDES.
+    # camelization (a genuine acronym it wants uppercased) go in
+    # INFLECTION_OVERRIDES.
     initializer "action_agent.inflections", before: :set_autoload_paths do
       engine_root = File.join(root.to_s, "")
       default = Zeitwerk::Inflector.new
@@ -74,15 +88,22 @@ class Engine < ::Rails::Engine
     # So the namespace answers to both. `const_missing` rather than an eager
     # alias because the controllers are autoloaded on demand, and naming them at
     # boot would load the whole dashboard.
-    # The router does not consult the autoloader's inflector, so an acronym
-    # host asks for ActionAgent::API::MCPServersController while the constants
-    # are Api::McpServersController. Rather than enumerate the pairs, an
-    # all-caps run in a missing constant is retried in the spelling default
-    # camelization produces: API -> Api, MCPServersController -> McpServers-
-    # Controller. Only the engine's own namespaces are touched, and only for a
-    # constant that is already missing.
+    # The router does not consult the autoloader's inflector, so its lookups
+    # miss in both directions. An acronym host asks for
+    # ActionAgent::API::TracesController while the constant is
+    # Api::TracesController: an all-caps run in a missing constant is retried
+    # in the spelling default camelization produces (API -> Api). A plain host
+    # asks for Api::McpServersController while the constant is
+    # MCPServersController (the file is in INFLECTION_OVERRIDES): a missing
+    # constant matching an override's default spelling is retried as the
+    # acronym constant, via DEFAULT_SPELLINGS — which also keeps caller code
+    # written against the pre-acronym names resolving. Only the engine's own
+    # namespaces are touched, and only for a constant that is already missing.
     inflection_shim = Module.new do
       def const_missing(name)
+        acronym = ActionAgent::Engine::DEFAULT_SPELLINGS[name.to_s]
+        return const_get(acronym, false) if acronym && const_defined?(acronym, false)
+
         relaxed = name.to_s.gsub(/([A-Z])([A-Z]+)(?=[A-Z][a-z]|\d|\z)/) { "#{$1}#{$2.downcase}" }
 
         return super if relaxed == name.to_s || !const_defined?(relaxed, false)
diff --git a/actionagent/test/engine_integration_test.rb b/actionagent/test/engine_integration_test.rb
index 2dc54821..054053ce 100644
--- a/actionagent/test/engine_integration_test.rb
+++ b/actionagent/test/engine_integration_test.rb
@@ -30,6 +30,16 @@ def setup
     assert ActionAgent::Api::TracesController < ActionController::API
   end
 
+  test "acronym constants answer to their default spellings" do
+    # A plain-inflection host's router camelizes the engine's mcp_* files to
+    # Mcp* names; the files define MCP* constants (INFLECTION_OVERRIDES), and
+    # the const_missing shim bridges the lookup.
+    assert_equal ActionAgent::MCPCatalog, ActionAgent::McpCatalog
+    assert_equal ActionAgent::PlaywrightMCPClient, ActionAgent::PlaywrightMcpClient
+    assert_equal ActionAgent::Api::MCPServersController, ActionAgent::Api::McpServersController
+    assert_equal ActionAgent::Api::MCPController, ActionAgent::Api::McpController
+  end
+
   test "every engine route maps to a shipped controller action" do
     ActionAgent::Engine.routes.routes.each do |route|
       controller = route.defaults[:controller]
diff --git a/actionagent/test/tool_discovery_test.rb b/actionagent/test/tool_discovery_test.rb
index 147690fb..3ee41771 100644
--- a/actionagent/test/tool_discovery_test.rb
+++ b/actionagent/test/tool_discovery_test.rb
@@ -250,7 +250,7 @@ def tool_named(name, body = tools_response)
 
 # The MCP Services API: detected servers unioned with the default catalog,
 # and starting a catalog server inside a sandbox.
-class McpServersApiTest < ActionDispatch::IntegrationTest
+class MCPServersApiTest < ActionDispatch::IntegrationTest
   def setup
     ActionAgent::Agent.delete_all
     ActionAgent::TelemetryTrace.delete_all
@@ -415,11 +415,11 @@ def server_named(key, body = servers_response)
   end
 
   test "a catalog server resolves to its entry and its launchability" do
-    assert ActionAgent::McpCatalog.launchable?("playwright")
-    assert_not ActionAgent::McpCatalog.launchable?("github")
-    assert_nil ActionAgent::McpCatalog.find("nope")
-    assert_equal "Playwright", ActionAgent::McpCatalog.display_name("playwright")
+    assert ActionAgent::MCPCatalog.launchable?("playwright")
+    assert_not ActionAgent::MCPCatalog.launchable?("github")
+    assert_nil ActionAgent::MCPCatalog.find("nope")
+    assert_equal "Playwright", ActionAgent::MCPCatalog.display_name("playwright")
     # An unknown key displays as itself rather than blank.
-    assert_equal "acme", ActionAgent::McpCatalog.display_name("acme")
+    assert_equal "acme", ActionAgent::MCPCatalog.display_name("acme")
   end
 end
diff --git a/docs/framework/v2-extraction-roadmap.md b/docs/framework/v2-extraction-roadmap.md
index 15d0cc54..e21c7f6e 100644
--- a/docs/framework/v2-extraction-roadmap.md
+++ b/docs/framework/v2-extraction-roadmap.md
@@ -82,7 +82,7 @@ JSON-RPC, served by `actionagent`.
 On the client side MCP is still pass-through only: `mcps:` options are
 normalized into each vendor's *remote* MCP format (the LLM vendor's servers
 do the connecting), and the only client in either gem
-(`ActionAgent::PlaywrightMcpClient`, also in `actionagent`) speaks just
+(`ActionAgent::PlaywrightMCPClient`, also in `actionagent`) speaks just
 enough JSON-RPC for one server. Remaining for v2: a general MCP client in
 `activeagent` (stdio/HTTP, `tools/list` discovery → routable actions) that
 turns any MCP server's tools into agent actions.