Engine MCP

The engine MCP server (in checkout launch)

Sedulous.Tools.Mcp is the engine's headless MCP host. This skill covers what only makes sense INSIDE the engine checkout: building and wiring the host. The operating manual (workflows, validation loops, per tool gotchas) is a SHIPPING doc the host serves to any connected agent: read docs://McpGuide.md via resources/read right after connecting (on disk: Documentation/Shipping/McpGuide.md).

Build and wire

• Build: cd Code && BeefBuild -workspace=. -config=Debug -platform=Linux64 -project=Sedulous.Tools.Mcp (binary: Code/build/Debug_Linux64/Sedulous.Tools.Mcp/Sedulous.Tools.Mcp).
• Wire: claude mcp add engine -- <repo>/Code/build/Debug_Linux64/Sedulous.Tools.Mcp/Sedulous.Tools.Mcp (stdio; the server identifies as engine-mcp).
• Run it from inside the checkout, or with the cwd in it: the docs:// resources and known_issues resolve Documentation/Shipping/ by walking up from the executable, then the cwd.
• STDOUT is the wire; engine logs go to stderr.

The editor host (the same surface, the LIVE project)

The editor serves the same engine tools over HTTP for the project it has open (server name engine-editor-mcp; host_info.host.kind = editor), so an agent works on what the user is looking at: one content database, one writer. Enable it in Preferences (MCP: enabled, port, token), or for one run: Sedulous.Tools.Editor <project> --mcp [--mcp-port <n>]. The default port is 7405; the token is minted on first enable and written to <user-data>/mcp-token (~/.local/share/Sedulous/mcp-token on Linux).

• Wire: claude mcp add --transport http engine-editor http://127.0.0.1:7405/mcp --header "Authorization: Bearer $(cat ~/.local/share/Sedulous/mcp-token)".
• The host lives with the project: it starts when a project opens and stops when it closes. Calls are answered once per frame on the editor's main thread; a tool that waits on the editor (a cook) keeps the call open until it finishes.
• project_create and project_open are the stdio host's alone: the editor's project is the editor's.
• The action bridge (action_list, action_state, action_execute) is everything a user can do by menu, chord, toolbar or context menu, over the ACTIVE page: list them first (the enabled flag is the answer over the active page; page_open the page an action needs), then execute by id. action_execute runs unattended: a dialog the action would open is closed as cancelled and named under suppressedDialogs. The action then most likely did nothing, so use a dedicated tool for that step or ask the user; never retry it blind.
• The page tools (page_list, page_open, page_reload, page_close) are the editor host's alone, and so are the scene page's live tools (selection_get, selection_set, simulate_start, simulate_stop, entity_inspect, component_set, each addressed by the page's asset guid). entity_inspect is the inspector's view of one entity (hierarchy, transform, every component's fields, asset references as guids, enums by name), the primary selection by default. component_set is the write half: ONE field of one component through the editor's undo path, one step per call labelled mcp, the page dirty after (nothing saves until the page's Save or file.save); value takes the shape entity_inspect shows: numbers, booleans, strings, guids, vectors, colours, quaternions, an enum case by name or number, an asset guid (or null) for a reference, an entity guid (or null) for an entity reference. Refused while the page simulates, on a read-only field, on a list or structure, on a wrong shape: nothing changes then. Read, write, read again. viewport_camera_get / viewport_camera_set read and move the viewport's editor camera (position, yaw and pitch in degrees, or a lookAt point; editor state only, no undo step), and viewport_screenshot writes what the viewport renders to a PNG (default under <user-data>/screenshots) and returns the path and size. It brings the page to front (a hidden viewport never renders) and waits for the frame, so give it a few seconds. The image has the grid, the markers, the selection's gizmo and the tool's hint text (selection_set an empty list first for a cleaner shot), not the panels docked over the viewport. To look at something: viewport_camera_set with lookAt, then viewport_screenshot, then read the file. A scene_write or prefab_write over an asset the user has open reaches its page at once: a clean page reloads in place, a page with unsaved edits keeps them and warns the user. Never write over it again hoping to win; ask, or page_reload with force only when the user said to discard.