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MCP tools

When an AI tool connects to your world, it discovers the available MCP tools automatically — names, descriptions, and parameters all arrive over the connection itself, and clients are notified when the set changes. You don’t invoke tools by name: describe what you want in plain language and the agent picks the right calls.

Which tools an agent sees depends on its access:

  • Read-only connections see only the reading and search tools.
  • Read-write connections (an editor or owner, or a read-write API key) also see the authoring tools.
  • The world-switching tools appear only on the connector, not on a single-world connection.
  • update_world_instructions appears for the world owner — and for editors when the owner has allowed editors to edit the world instructions.

The exact set evolves with Orbismo — the list your agent discovers on connection is always authoritative — but it covers:

Tools
Switching worlds (connector only) list_my_worlds, set_active_world.
Session get_world_context (the world’s schema), get_world_instructions (the world instructions) — agents call these first.
World instructions (owner; editors when allowed) update_world_instructions — lets the agent write or revise the world instructions for you.
Reading and search search_entities, get_entities, get_entity_lore, query_relationships, get_timeline, search_lore (semantic), audit_world (consistency checks).
Authoring (read-write) create_entities, update_entity, delete_entity.
Lore (read-write) create_entity_lore, update_entity_lore, delete_entity_lorelore lives on an entity as titled chunks, each authored and edited on its own.
Relationships (read-write) create_relationships, update_relationship, delete_relationship.

A few durable conventions: entities are referenced by slug (person/john_smith); the create tools accept up to 100 items in a single call; paginated reads return a cursor that must be re-sent with the same filters that produced it; and update_entity_lore replaces a chunk’s content wholesale rather than patching it — agents read the chunk first, then send the full revised text.

When an agent’s search returns less than you expect, it’s usually one of these:

  • Property filters compare as text by default. Date and number fields need an explicit cast, and values that can’t be cast ("end of summer" as a date) are skipped silently rather than erroring. Store dates as ISO and numbers as bare digits — and put those rules in your world instructions so every agent applies them.
  • One property filter per search, no OR. For a date window, get_timeline has native bounds; for questions that span connections, traverse with query_relationships and narrow from there. A missing property never matches a comparison.
  • search_lore matches by meaning, scoped by entity type or a single entity — not by tags.

For ready-made worlds that put these tools to work — starter templates, installable mini apps, and creative ways to use Orbismo — see the Orbismo Playbook.


If an agent says a tool isn’t available, its connection probably doesn’t have the right permission, or — on the connector — no world is active yet. See Troubleshooting.