Build 3D web apps: physics, audio, music, Blender import. Live edits, undo, versions, publishing.
Connect Remote server
claude mcp add --transport http r3 https://mcp.r3js.org/mcp --header "Authorization: Bearer <YOUR_API_KEY>"{
"mcpServers": {
"r3": {
"url": "https://mcp.r3js.org/mcp",
"headers": {
"Authorization": "Bearer <YOUR_API_KEY>"
}
}
}
}{
"servers": {
"r3": {
"type": "http",
"url": "https://mcp.r3js.org/mcp",
"headers": {
"Authorization": "Bearer <YOUR_API_KEY>"
}
}
}
}Settings > Connectors > Add custom connector
URL: https://mcp.r3js.org/mcpReplace the values in angle brackets with your own. Keys stay on your machine; we never see them.
Tools 80 found in our last check
r3_docs_listEvery R3 document this server can give you, IN READING ORDER, with what each one covers and how big it is. R3's documentation begins here: no model has R3 in its pretraining, and code written from tool descriptions alone saves cleanly and then silently does nothing. r3_docs_read…
r3_docs_readReturn one R3 document in full, or one API symbol. Paths come from r3_docs_list: r3_docs_read("CODE_PATTERNS.md") how a Code component is written (reading order 1) r3_docs_read("PHYSICS_USAGE.md") colliders, rigid bodies, joints r3_docs_read("HOWTO_PHYSICS.md") one task step by…
r3_whoamiReport the R3 account you act for, how you are connected (an agent key, or an app connection made with Sign in with R3), what you are allowed to do, the account's plan (its name and how many live projects it allows and uses: going live needs one), and whether the R3 platform is…
r3_project_createCreate a new R3 project and save it to the user's account. Produces a complete, openable project — scene, world, camera, renderer, lighting, audio listener, music transport and OrbitControls (anyone who opens it can turn and zoom the view) — ready for components to be added. Pas…
r3_project_listList the projects this R3 account can work on — its own and its teams' — last updated first, with the projectId every other project tool takes. It is how a project the user names ("my slot machine") rather than giving an id is found: search for it; its projectId is what r3_proje…
r3_project_loadList the components in an existing R3 project — what it contains and, for each one, its entityRef: the name code addresses it by (`this['mesh_cube_1']`). Read this before writing any code for a project, and after any tool call whose outcome was reported as unknown, to see what a…
r3_preview_createCreate a shareable preview link for a saved R3 project, so a person can open it in a browser and see it running. The link is valid for 7 days and does NOT make the project public; making a new one is free. It is how the user sees what you built. Takes the projectId returned by r…
r3_preview_removeRemove the preview link of an R3 project: every preview link to it stops working at once (teammates' too). Only when the user asked for it, or when the preview link is what blocks an r3_project_delete the user asked for: a preview link is temporary, so it may then be removed wit…
r3_publish_livePublish an R3 project live: makes a RELEASE (a frozen copy) of the project as it is now and makes it the one its public live URL shows, for anyone. Only when the user asked for it. Changing the project does NOT change the live site; r3_publish_live does: on a project that is alr…
r3_unpublish_liveTake a live R3 project offline: its public live URL stops working at once, and the live-project slot it used on the plan is free again. Only when the user asked for it. Other people open a live project, so one that blocks an r3_project_delete goes offline only once the user has…
r3_release_listList the releases of an R3 project, newest first: number, date, who made it, note, size, which one is LIVE (what the public URL shows), pinned, and releases in the trash (restorable for 7 days). Also says whether the project has saved changes that are not live yet: saving does N…
r3_release_rollbackMake an earlier release of a live R3 project the one its public URL shows again (rollback, or forward again). Only when the user asked for it. The project must be live; this never uses a plan slot. A release in the trash or one marked incomplete is refused. Nothing is deleted: t…
r3_publish_settings_readRead the publish settings of one of the user's own R3 projects in this environment — what the app's Deploy → Settings shows: Works on (keyboard / touch / both / not tested), the SEO title and description that search engines and link previews show, how the live page starts (Start…
r3_publish_settings_setChange publish settings of one of the user's own R3 projects in this environment — the app's Deploy → Settings. Only the settings named change (the rest stay as they are). Only when the user asked for it, or approved the text: these settings shape the PUBLIC live page — its titl…
r3_project_renameRename a project: the name shown in the user's project list, the editor's title and the live page. The same change as clicking the title in the R3 editor, kept at once in the project's live copy (every open R3 tab shows it). The public address does not change: a preview or live…
r3_project_remixRemix a project: copy the published release of a project into a NEW private project in this account. The source is a Community or live project whose author allowed remixes (for now R3's own starters and showcase projects), or one of the account's own. The files it uses are copie…
r3_project_deletePermanently delete an R3 project. With the project:delete:created right (on by default), only a project YOU created (this agent key or app connection) — use it to clean up your own abandoned attempts; the user's own projects and other agents' are refused. With project:delete:own…
r3_factory_listList the R3 factories available to r3_factory_run, with each one's options, types and defaults. A factory builds a complete, correctly-wired object — a cube is a mesh plus geometry plus material plus colour, already connected. Call this before r3_factory_run if you are unsure of…
r3_factory_runAdd an object to an existing R3 project — a cube, sphere, terrain, lighting, a physics body, and so on. Each factory builds a complete, correctly-wired object (mesh + geometry + material + colour, already connected), so you never assemble components by hand. Kept at once in the…
r3_code_writeAdd or replace a Code component: JavaScript a project runs. It runs on ONE event you choose (`event`): RENDER_BEFORE (default) every frame, for movement (held keys: this.keysPressed); KEY_DOWN / KEY_UP once per press / release; MOUSE_CLICK, SWIPE, MUSIC_BEAT, PHYSICS_COLLISION o…
r3_code_readRead back what a Code component actually contains — its full JavaScript source and the event it runs on. r3_code_write reports what it wrote; this reports what is there. Use it before replacing a script, so an edit builds on the real source instead of overwriting it blind, and a…
r3_help_writeSet the instructions that ship WITH a project — controls, what to press, what it does. R3 renders them in a modal behind a floating "?" button and the H key, in the editor and in the live portal alike, so whoever opens your preview link can read them. This is the built-in surfac…
r3_component_setSet one or more properties on a component that already exists in a project — a material's roughness, a mesh's position, which material a mesh uses. Kept at once in the project's live copy: every R3 tab with the project open shows it now, no editor needed and nothing to save (r3_…
r3_component_readRead back what components actually hold — a material's colour and roughness, a mesh's position, which material it uses. r3_project_load gives you the names; this gives you the values behind them. Pass SEVERAL entityRefs in one call — telling six similarly-named materials apart i…
r3_terrain_heightHow high the ground of a heightfield terrain is at the world (x, z) positions you ask, exactly as physics and the drawn terrain have it, plus the terrain's lowest and highest point, centre, size and footprint. Use it to place something ON a terrain: an object stands on the groun…
r3_component_boundsThe size and place of meshes and imported models, in R3 units (metres): the world-space box around each (min, max, size, centre), the mesh's scale, rotation and parents applied. Name a Mesh, or the root Empty of a Blender model (r3_blender_import makes one, named "<model>_root")…
r3_component_addAdd one component of ANY registered type — a collider, a rigid body, a joint, a light, a material, a geometry … — to a saved R3 project, with its values and references set before it is created. Kept at once in the project's live copy: every R3 tab with the project open shows it…
r3_editor_openOpen a project in the R3 editor the user has open in their browser (their most recently used R3 tab) and focus it, so they see it. A project already open there is just focused (never reloaded). It is how the user gets to see the project you are working on, and how a tab gets the…
r3_editor_inspectRead what components hold RIGHT NOW in an R3 tab that has the project open: runtime values included — a moving body's position while the project runs. Use it to debug live behaviour. It needs a tab with the project open (r3_editor_open opens one). r3_component_read reads the kep…
r3_editor_setThe same tool as r3_component_set (this is its older name): change properties of a component, kept at once in the project's live copy: every R3 tab with the project open shows it now, no editor needed and nothing to save. Name the component with componentId or entityRef. `values…
r3_editor_codeThe same tool as r3_code_write (this is its older name): replace a Code component's code, kept at once in the project's live copy: every R3 tab with the project open runs the new code now, no editor needed and nothing to save. Name it with componentId or entityRef and pass baseV…
r3_editor_createThe same tool as r3_factory_run (this is its older name): add an object — a cube, sphere, light, physics body … — kept at once in the project's live copy: every R3 tab with the project open shows it now, no editor needed and nothing to save. r3_factory_list lists the factories a…
r3_editor_add_componentThe same tool as r3_component_add (this is its older name): add one component of ANY registered type — a collider, a rigid body, a joint, a light, a material, a geometry … — with its values and references set before it is created, kept at once in the project's live copy: every R…
r3_editor_deleteDelete components from the project the user has OPEN in their R3 editor, exactly as the editor's delete dialog asks it — in TWO calls. First call WITHOUT `confirm`: it returns the plan and changes nothing — the selected components, what only they use (their geometry, material, c…
r3_editor_undoUndo the last change YOU (this agent key or app connection) made to a project: everything one of your tool calls changed is undone together, and the user sees it at once in any R3 tab that has the project open. Use it when your own change was wrong or the user asks you to take i…
r3_release_restorePut a project's working copy back the way one of its releases (saved versions) had it: components added since are removed, removed ones come back, values and scripts go back to that version (each script as a new version on top of the current one), and the name. The user sees it…
r3_editor_runPress the Run buttons of the user's open R3 editor: start physics, code, audio and music (all of them, or the ones named in `systems`), exactly as the user's own click does — a paused simulation resumes. Use it to TEST what you built: run it, then look with r3_editor_capture and…
r3_editor_stopPress the Stop buttons of the user's open R3 editor: stop physics, code, audio and music (all of them, or the ones named in `systems`), exactly as the user's own click does. Stopping physics puts every body back where it was placed. It stops every project open in that tab. Chang…
r3_editor_captureCapture the canvas of a project open in the user's R3 editor — the scene as it looks NOW, running physics included — and LOOK at it: the answer is an image. Call it after a visual change (r3_editor_set, r3_editor_create, r3_editor_code …) to check what you built, and after r3_ed…
r3_editor_set_preview_imageUse what the project's camera shows NOW, in the user's open R3 editor, as the project's share image: the picture its live page, link previews (social cards) and the showcase show, used when the project is next published (r3_publish_live, or Publish update in the editor). The edi…
r3_entity_listList this R3 account's entity templates: reusable bundles (a ship, a lamp post) saved from an Entity in a project, each with its current version and member count. community: true lists everyone's public templates instead. r3_entity_read shows one template's members and versions;…
r3_entity_readRead one entity template (this account's, or a public one): its current version, the members of the version read (type, name, entityRef; value components such as positions and colours are counted, they belong to their member), the shared code modules it imports, and its recent v…
r3_entity_save_templateSave an Entity of a project as an entity template version: its members (the components bound to it, with the positions, rotations and colours they hold), a description and a picture. `description` is required (20..1000 characters): write it from the Entity's components and its c…
r3_entity_importPut a copy of an entity template (this account's, or a public one) into a project: every member with fresh ids, its positions and colours as saved, bound to a new Entity that starts DORMANT (started: false: its code, sounds and physics wait until r3_component_set sets started: t…
r3_entity_updateBring the copies of an entity template in this account's projects up to its newest version. Without reportId it only reports, per project: what the template changed that the project did not (taken), what the project changed itself (kept, e.g. a moved ship keeps its position), sc…
r3_entity_assignPut many components of a project into one Entity in a single change, instead of r3_component_set {"entity": …} once per component. Name them in members (entityRefs or ids), or let match find them ({"prefix": "ship1_"} on the entityRef, {"type": "Mesh"}, or both). Each one's valu…
r3_component_renameRename a component: its entityRef, the name scripts address it by (this['name'] / this.name), and its display name when that is where the entityRef came from. Name it by entityRef or componentId. Without planId it only PLANS and changes nothing: it checks the new name (refused:…
r3_module_listList this R3 account's shared code modules: named pieces of script stored once (e.g. "ship-core") that any Code component in any project imports with `const core = this.import('ship-core')`. Each with its latest version. r3_module_read shows one's code; r3_module_write creates o…
r3_module_readRead one shared code module: its code, its version (the baseVersion r3_module_write needs), the latest version, its notes, and how many of this account's projects use it. Your own module by name; someone else's PUBLIC module by moduleId. version reads an older version. A long mo…
r3_module_writeCreate a shared code module (baseVersion 0) or write its next version (baseVersion = the version you read). The code is a FUNCTION BODY that returns the exports, e.g. `return { createShip(host, config) { … return {start, update, dispose, api}; } };`. It runs once per run with `t…
r3_module_usageWhich of this account's projects (and entity templates) import one of your code modules: per project the scripts that import it, the version it runs, and whether that version is pinned or follows the latest. Projects of other accounts that import a public module of yours are onl…
r3_module_pinChoose which version of a shared code module ONE project runs: version n pins it (the project keeps that version when the module changes), version null follows the latest again. moduleId names someone else's PUBLIC module (it is then the project's module of that name). The pin l…
r3_blender_listList the Blender models this R3 account has uploaded — one per .blend file name, the current version of each — with what it will produce: how many Blender objects land in the scene, how many meshes and materials, its screenshot, and any PENDING update (a re-upload that changes m…
r3_blender_importAdd a Blender model the account has uploaded (its current version) to an existing R3 project — the whole model, or only the meshes you name. Every Blender mesh object becomes an R3 Mesh keeping its own position, rotation, scale and origin, with its geometry, materials and textur…
r3_blender_updateA re-uploaded Blender model is always its latest version; the user's projects keep the meshes they have until asked. This tool asks and answers that one question: choice update_projects without reportId shows which projects and entity templates use an older version (or an earlie…
r3_blender_copiesDoes this project hold the same Blender model more than once (two whole imports side by side)? Answers "N copies of <model>: … Keep one?" with each copy (its Entity, entityRef, part count) and its delete plan. It changes nothing: which copy stays is the user's choice, and the ot…
r3_blender_uploadSave a .blend you made or changed (in Blender, through a Blender MCP) as the newest version of one of the user's Blender models: the model is named by the file name, so "monster-truck.blend" adds a version to the user's monster-truck model, or makes the model. A tool argument ca…
r3_blender_downloadGet a .blend of one of the user's OWN Blender models (from r3_blender_list) to open in Blender: the current version, or the version fileId names. Answers a one-time download ticket (5 minutes) and the download endpoint (URL, method, Authorization header); the response body is th…
r3_blender_draft_pushWhile you build a model in Blender for the user, push an APPLIED copy of your working .blend after each step (body done, wheels done, materials done): the user's Blender page shows it as a 3D preview they can orbit. A draft is not a saved version: one draft per user, the newest…
r3_image_listList the images this R3 account owns, with the URL to use for each one. That URL is exactly what R3ComponentTexture.url takes, so this is how you find the account's own artwork — a wood grain, a logo, a skybox — and then point a texture at it with r3_component_set. Search by nam…
r3_audio_listList the audio files this R3 account owns, with the URL to use for each one. That URL is exactly what R3ComponentAudio.url takes, so this is how you find a sound the account already has — a footstep, a drum hit, a music bed — and then point an Audio component at it with r3_compo…
r3_image_createStore a small image YOU generated in this R3 account's image library and get back the URL for it — the value R3ComponentTexture.url takes. This is how you make a checkerboard, a gradient, a test grid or a noise tile and then actually put it on something with r3_component_set. Pa…
r3_texture_createMake a matching, seamlessly tiling texture SET for a material: a colour map, a normal map and a packed ambient-occlusion / roughness / metalness map, rendered by R3 from a procedural recipe (seeded noise, stones, bricks …). Nothing is uploaded and it is free. The maps are stored…
r3_texture_readRead one texture set: its name, size, tile size, the three map urls, the numbers its render measured, the sets it was edited from, and the full RECIPE (the editable source). The account's own sets, or anyone's public one. To change a set, r3_texture_update makes a new version of…
r3_texture_updateChange a texture set the account owns: its look (controls: seed, scale, colours, contrast, bumpiness, roughness {min, max}, metalness, size, tileWorldSize, height, applied to the set's own recipe; `scale` multiplies its pattern, so 2 is twice as fine as now) or a whole new `reci…
r3_texture_applyWire a texture set to a material in a project: the colour map to `map`, the normal map to `normalMap`, the ambient-occlusion / roughness / metalness map to `aoMap` + `roughnessMap` + `metalnessMap` (for a set without metal its blue channel is 0, so a metal map left by an earlier…
r3_sound_createMake a sound (a 48 kHz WAV in the account's audio files) from a recipe that R3 renders: layers of synth / fm / noise / sample sources, each with an envelope and effects (filter, distortion, bitcrush, delay, reverb, compressor, tremolo), and a master stage that can make a seamles…
r3_sound_readRead the RECIPE a sound was made from (the editable source), with its name, url, duration, whether it loops and the sound it was edited from. The account's own sounds, or anyone's public one; an uploaded file has no recipe. To change a sound, r3_sound_update makes a new version…
r3_sound_updateChange a sound the account owns: overrides {seed, duration, channels} applied to its own recipe, or a whole new `recipe` (read the current one with r3_sound_read, change it, pass it here; r3_docs_read("SOUND_RECIPES.md") has the format). The sound itself never changes: the chang…
r3_song_readRead a project's Song: its tracks (each plays Patterns, DrumGrids, Beats or Audio files in clips placed in bars), automation lanes (keyframes on a track's or the master's gain, pan or effect settings), sections, master chain and length, with every source as its entityRef, plus a…
r3_song_updateChange a project's Song with small typed changes, or make a new Song (create). The changes are applied in order and kept as ONE change (one undo step, every open R3 tab shows it): ops: setSong, setSections, setMaster, addTrack, setTrack, removeTrack, setClips, addClip, moveClip,…
r3_assets_unusedThe account's images, models and audio files that nothing uses — no project, no entity template, no other user's project — with each one's size and date, biggest first, and the total. The same report as the R3 app's Settings → Storage, by the same rules the deletes use. A model…
r3_asset_deleteDelete one of the account's images, models, audio files, Blender models (kind blender: a whole uploaded .blend with every version; its meshes in use stay) or texture sets (kind textureSet: the set and its maps, r3_texture_create made it) — the same reference-guarded delete as th…
r3_asset_shareShow one of the user's OWN images, audio files or texture sets in the R3 Community, or hide it again: the same switch as 'Show in Community' in the R3 app. public: true makes it visible to every R3 member, who can then find it in the Community lists and use it in their own proje…
r3_bug_reportSend R3 a bug report about R3 ITSELF (the engine, the editor, these tools), in the user's name and naming you (your agent key or app connection). It becomes one of the user's support issues, which only the user and R3's team see. Use it when R3 does something its documentation s…
r3_bug_reports_mineThe user's own support issues — bug reports and questions they or their agents (agent keys and app connections) sent R3 — newest first, with status, date, the project and whether an agent filed it (and which), each with its link. It shows whether a fault is already reported, bef…
r3_roadmap_listThe public R3 roadmap: what is planned, in progress, proposed by the community and shipped, with each item's vote count and whether the user has voted for it — plus the user's OWN suggestions still awaiting R3's approval, marked pending, and the ones R3 declined, marked declined…
r3_roadmap_upvoteAdd the user's vote to a public roadmap item (its id from r3_roadmap_list), when the user wants it or it covers what you were about to suggest. One vote per user: an item the user already voted for stays voted, and this never removes a vote. Needs the roadmap:vote right.
r3_roadmap_suggestSuggest a feature for R3's public roadmap, in the user's name and naming you (your agent key or app connection). It is HELD until R3's team approves it: not public, not votable, until then. r3_roadmap_list shows whether an item already covers it (r3_roadmap_upvote votes for that…
r3_project_changesWhat OTHER people changed in a project — the user in any R3 tab, their other agents — oldest first, grouped per author and per thing: properties set, code and help updated (with versions), components added, deleted or restored, the project renamed. Your own changes are never lis…
Headers
| Name | Description |
|---|---|
AuthorizationOptional, secret | Optional. Leave empty to sign in with R3 (OAuth). Or Bearer r3agent_… from r3js.org → Settings → AI & apps |
Details
| Endpoint | https://mcp.r3js.org/mcp (Streamable HTTP) |
| First published | 13 Nov 2026 |
| Last updated | 13 Nov 2026 |
| Registry name | org.r3js/r3 |
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