Roblox Studio MCP Server

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Roblox Studio, controlled by your agent

BloxForge connects an MCP client to a lightweight Studio plugin over localhost:

Claude Code / Codex / Cursor / Gemini
                  ↕ MCP
          BloxForge Node server
                  ↕ localhost
          Roblox Studio plugin

No BloxForge cloud account is required. Your place data and bridge traffic stay on your machine.

Related MCP server: Roblox Studio Ultimate MCP Server

Quick start

Requires Node.js 20 or newer.

1. Allow Studio HTTP requests

In Roblox Studio, open Game Settings → Security and enable Allow HTTP Requests.

2. Install the Studio plugin

Run this once, and again whenever you update BloxForge:

npx -y @princeofscale/bloxforge@latest --install-plugin

Fully close and reopen Roblox Studio after installing or updating the plugin.

3. Connect your MCP client

claude mcp add bloxforge -- npx -y @princeofscale/bloxforge@latest

codex mcp add bloxforge -- npx -y @princeofscale/bloxforge@latest

gemini mcp add bloxforge npx --trust -- -y @princeofscale/bloxforge@latest

Add this to .cursor/mcp.json:

{
  "mcpServers": {
    "bloxforge": {
      "command": "npx",
      "args": ["-y", "@princeofscale/bloxforge@latest"]
    }
  }
}

Use @next instead of @latest to test release candidates.

MCP clients normally start BloxForge before Roblox Studio. The message Waiting for Studio plugin to connect... means the server is healthy and idle. Open a Studio project whenever you are ready.

4. Verify everything

Start your MCP client, open a place in Studio, and run:

npx -y @princeofscale/bloxforge@latest verify

File-backed projects: Rojo, Rokit, Wally

For file-backed projects, local files are the source of truth and Rojo owns the continuous Studio sync. BloxForge drives the real CLIs — it never reimplements their semantics:

Codex / Claude → BloxForge MCP tools → local Luau files → rojo serve → Studio
                                             ↘ validate / format / test

Getting a project running

project_reconcile_plan reads all of it at once — Rojo project, toolchain pins, Wally lock, package mounts, sourcemap, rojo serve — and returns the ordered steps that would make the project ready, each marked automatic or blocked. project_reconcile_apply runs them under a single-writer lease, re-reading the state after every step, and finishes with a strict verify.

It restores declared state and never invents new state: installing the exact version rokit.toml pins and the packages wally.lock already resolved is a repair; choosing a new version or resolving a new lock is a decision, and those steps come back blocked with the [automation] flag that would permit them. Defaults, overridable in bloxforge.toml:

[automation]
installPinnedTools    = true     # restore what the manifest already pins
installLockedPackages = true     # restore what the lock already resolved
generateSourcemap     = true
startRojo             = true
restartManagedRojo    = true

updateToolPins        = false    # each of these decides new state
updateWallyLock       = false
editRojoProject       = false
migrateAftmanToRokit  = false

Each run journals to .bloxforge/reconcile/<runId>.json, so passing the same runId resumes an interrupted run instead of repeating finished steps.

The individual steps stay available, and doing it by hand is the same order:

1. Pin your tools in rokit.toml, then rokit_status → rokit_install. A project pinned to a version whose shim is not installed fails with the install command; it never quietly runs a different global Rojo.

2. wally_validate_lock, then wally_install_apply, then wally_verify_rojo_mapping to confirm the installed package directories are actually mounted by the project.

3. rojo_detect_projects → select an explicit project if more than one is found → rojo_validate_project.

4. rojo_serve_start for loopback-only live sync.

5. Read and edit local sources with the rojo_*_source tools; run targeted StyLua, Selene, or Luau checks on the files you touched.

6. Use the Studio bridge for inspection, playtests, runtime debugging, UI, and Instances outside the Rojo-managed roots.

7. Bring Studio changes back only through rojo_syncback_plan → review → rojo_syncback_apply with the planHash the preview returned.

Set BLOXFORGE_PROJECT_ROOT when BloxForge is launched outside the project directory. Every file path resolves through that root.

What is preview/confirm

Anything that writes files, installs packages, or mutates Studio in bulk is a plan/apply pair. The plan is immutable: rojo_syncback_apply requires the planHash from its preview and refuses a stale one, so an edit that lands between review and apply is never silently carried through.

Wally installs default to --locked so a stale lockfile fails instead of being rewritten. --locked is absent from the released Wally 0.3.2, so support is probed and a locked install is refused rather than quietly downgraded.

This supports partially managed projects (only selected roots such as scripts or packages) and fully managed project trees. BloxForge never treats unmanaged Studio Instances as deletion candidates. Stable Rojo 7.7+ native syncback is feature-detected; older stable versions retain the bounded plugin-based subset. BloxForge reports installation guidance when a tool is absent and never installs it silently.

Try it

Start with a focused request:

Inspect this place, summarize its architecture, identify runtime risks, and propose a safe implementation plan before changing anything.

Or let the agent execute an end-to-end workflow:

Build a six-stage obby with checkpoints and a timer, playtest it, inspect the runtime logs, and fix any errors you find.

Choose the right tool profile

Profiles keep tool discovery focused and reduce context use:

Some pre-4.0 toolchain wrappers (install_wally_packages, generate_rojo_sourcemap, build_rojo_project) remain discoverable for compatibility. The unsafe sync_pull, sync_status, and sync_push wrappers have been removed from MCP discovery; use the hashed rojo_syncback_plan → rojo_syncback_apply flow. See Known limitations for the mapping.

Select one with --profile <name> or BLOXFORGE_TOOL_PROFILE. Profiles control authorization where stated; load_toolset only expands schema visibility and cannot grant a denied tool. Invalid names fail startup.

Reliability and safety

BloxForge treats Studio as a recoverable local execution target:

• request acknowledgements, delivery leases, deduplication, and status lookup;

• safe retry rules that distinguish reads from mutations;

• explicit outcome_unknown handling after interrupted operations;

• bounded atomic recovery journals and payload-free p50/p95/p99 diagnostics;

• authenticated proxy forwarding with queryable primary request IDs;

• per-DataModel concurrency limits and backpressure;

• plugin session credentials and capability-scoped MCP clients;

• localhost-only bridge binding by default, with authenticated non-loopback opt-in;

• mutation confirmation, dry-run, backup, and rollback-oriented tools.

Authorization is by declared effect, not by a tool's name. Every tool states its own studio.*, local.files.*, local.process.execute, network.external, assets.upload, and playtest.control effects; the field is required, so a new tool cannot inherit a wrong guess. The inspector profile permits only Studio and local-file reads, and the builder profile denies arbitrary Luau execution.

See Architecture and Security policy for the full model.

Optional Roblox Open Cloud access

Most features need no Roblox credentials. Creator Store access and asset uploads can use an optional Open Cloud API key with the required asset scopes:

export ROBLOX_OPEN_CLOUD_API_KEY="your-api-key"

Never commit the key or place it in shared MCP configuration.

Develop locally

npm ci
npm run build:all
npm test
npm run lint

Plugin builds only write repository artifacts. Set MCP_PLUGINS_DIR to an explicit temporary directory when testing installation; builds never infer or modify your normal Studio plugin directory.

Useful release checks:

npm run test:plugin:smoke        # compiled Luau output
npm run test:plugin:installer    # both CLIs install atomically
npm run docs:check               # tools reference matches the definitions
npm run metadata:check           # package metadata matches the README
npm run verify-package           # packed tarball contents
npm run release:check            # everything above, in order

Integration jobs drive the real binaries and run in CI:

npm run test:rojo:integration       # pinned Rojo 7.7.0
npm run test:toolchain:integration  # pinned Rokit, plus Wally's actual --locked support

docs:generate reads packages/core/dist, so build core before checking docs.

Documentation

• Tool reference

• Architecture

• Known limitations

• Agent guide (working on BloxForge)

• Troubleshooting

• Security policy

• Changelog

Community

• Releases and project news: official Telegram channel

• Bugs and feature requests: GitHub Issues

• Security reports: follow the private process in SECURITY.md

License

MIT © BloxForge contributors.