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MCP registry

Buril ships 9 MCP entries out of the box. Each is either an in-process MCP endpoint (the bridge itself, on HTTP :8766/rpc and TCP :8765) or an external Python MCP server that Buril spawns when needed.

The MCP standard (Model Context Protocol) lets any MCP-compatible client (Claude Desktop, VS Code, custom clients) call Buril's tools, and lets Buril call out to other MCP servers. The same registry surfaces both directions.

The 9 default entries​

#NameTypeWhat it exposes
1bridgeIn-process, HTTP :8766/rpc + TCP :8765All 3,691 Buril ITools
2zbrushExternal Python (buril-zbrush-mcp)ZBrush 2026+ Python API — 75 zbrush_* tools
3daz3dExternal Python (buril-daz-mcp)Daz Studio 4.x bridge — 70 daz3d_* tools
4cc5External Python (buril-cc5-mcp)Character Creator 5 / iClone — character export pipeline
5vroidIn-process (TCP :9876)VRoid Studio bridge — 95 vroid_* tools
6cascadeurIn-process (TCP :9876)Cascadeur AI keyframes bridge — 85 cascadeur_* tools
7marvelousIn-process (TCP :9877)Marvelous Designer bridge — 80 marvelous_* tools
8pixel-mcpExternal PythonAseprite integration — pixel art editing
9pixellab-mcpExternal PythonPixelLab cloud (BYOK) — AI sprite generation

Entries 1, 5, 6, 7 are part of the bridge package (the in-process endpoints). Entries 2, 3, 4, 8, 9 are external Python packages — see installation below.

Wiring an external MCP server​

Tools → Buril → MCP Hub → Register External

The Hub prompts for:

  • Type (one of zbrush / daz3d / cc5 / pixel-mcp / pixellab-mcp, or custom).
  • Python executable (defaults to the first Python ≥ 3.11 on $PATH).
  • Server arguments (optional, server-specific).

The Hub:

  1. Spawns the Python process.
  2. Pipes its stdio through the MCP dispatcher.
  3. Calls tools/list to enumerate the server's tools.
  4. Registers each tool under the prefix family (zbrush_*, daz3d_*, etc.).
  5. Persists the registration to ~/.config/buril/mcp_registry.json so it survives Editor restarts.

Installing the Python packages​

PackageInstall
buril-zbrush-mcppip install git+https://github.com/Buril-ai/buril-zbrush-mcp.git
buril-daz-mcppip install git+https://github.com/Buril-ai/buril-daz-mcp.git
buril-cc5-mcppip install git+https://github.com/Buril-ai/buril-cc5-mcp.git
pixel-mcppip install pixel-mcp (community OSS, absorbed + extended)
pixellab-mcppip install pixellab-mcp (BYOK to PixelLab)

All five target Python 3.11+. Use a dedicated virtualenv to avoid conflicts with your system Python.

The bridge as a server (other clients calling Buril)​

The bridge's own MCP server is the most powerful entry point. External clients (Claude Desktop, custom MCP-compatible tools) can connect and call any of Buril's 3,691 ITools:

  • HTTP: http://127.0.0.1:8766/rpc (JSON-RPC 2.0).
  • TCP: tcp://127.0.0.1:8765 (line-delimited JSON).
  • stdio: Tools → Buril → MCP Hub → Expose via stdio (spawns a proxy that pipes stdio to the HTTP endpoint — useful for Claude Desktop which prefers stdio).

To wire Claude Desktop to Buril:

  1. Open Claude Desktop's MCP settings file (~/Library/Application Support/Claude/claude_desktop_config.json on macOS).

  2. Add:

    {
      "mcpServers": {
        "buril": {
          "command": "buril",
          "args": ["--mcp-stdio"]
        }
      }
    }

  3. Restart Claude Desktop. The 3,691 Buril tools are now available in Claude Desktop's tool menu.

The bridge as a client (Buril calling other MCP servers)​

Beyond the 9 default entries, you can register any MCP server via the Hub. Common third-party MCP servers that pair well with Buril:

  • Filesystem MCP — file operations outside the Unity project.
  • Browser-use MCP — give an agent a headless browser for asset references.
  • GitHub MCP — issue / PR creation, repo search.
  • Slack MCP — post build notifications.

Register via the Hub with Type: custom and the spawn command for the third-party server.

Headless / CI MCP​

In CI, the bridge can be invoked over MCP without the Editor UI:

buril --mcp-serve --port 8766 &
# now any MCP client can connect to http://127.0.0.1:8766/rpc

For Claude Code / Claude Desktop in CI:

buril --mcp-stdio | claude --tools-from-stdio

Security​

  • All MCP endpoints listen on loopback only by default. Remote connections require explicit --bind 0.0.0.0 and are gated behind OAuth 2.1 DCR (Dynamic Client Registration) — see /security.
  • External MCP servers (Python processes Buril spawns) run with the same OS-user privileges as the Editor. Restrict via OS sandboxing if you need stricter isolation.
  • The bridge logs every MCP call to Library/BurilCache/mcp_log/ for audit. Logs rotate daily.

Common issues​

SymptomFix
"Failed to spawn server"Python not on $PATH, or the package isn't installed in the active env. Check Hub error message.
"tools/list returned 0 tools"Server crashed during init. Inspect ~/.config/buril/mcp_log/<server>.log.
Bridge endpoint port conflictAnother service on :8766. Set BURIL_BRIDGE_PORT or Tools → Buril → Settings → Network → Bridge port.
Claude Desktop can't see Buril toolsRestart Claude Desktop after editing claude_desktop_config.json. The stdio handshake happens at startup only.