Extend Pluto

Developers extend Pluto Core through four interfaces. Nothing else is a supported extension point.

Interface	Add	Admins then
ITool	A new tool type, such as a call to your order system. Optionally with IToolAuthoring, so admins fill in settings instead of writing an Input Schema.	Pick the new name in a tool’s Tool Type.
IModelProvider	A connection to another model provider.	Name the class in an Agent Model’s Model Adapter Class.
IContextProvider	Context that needs more than a Field Set.	Pick the class in a context provider’s Implementation Reference.
IToolAuthorizationPolicy	Rules that allow, deny, or require approval call by call.	Pick the class in the agent’s Tool Authorization Policy Class.

Core runs each one inside its own lifecycle. The extension returns a result. Core records it, retries it, or pauses the run. An extension never writes Core’s records itself.

Before you write one

1. Read the extension contract. It lists every rule Core relies on: access checks, size limits, error types, and how to report an outcome Core cannot see.
2. Choose the tool type’s Effects carefully. It decides whether Core may repeat a call. See Effects.
3. Return records as record sets, not as text. Core protects sensitive fields and filters records for the person only in record sets.
4. Use only Pluto’s global Apex and the contract’s rules. Then your extension can stay private under any license. See License.

Register a tool type

A tool class needs an Agent Tool Type custom metadata record, deployed with it:

Field	Value
Label and name	What admins type in Tool Type, such as LookupOrder
Tool Class	Your class
Implementation Type	Apex
Effects	Stays in This Org, Reads Outside Systems, or Changes Outside Systems
Description	One sentence for admins

Test it

Test against the exact Pluto Core version you will install. At least cover: sharing and field access under a standard user, timeouts, permanent and retryable errors, oversized responses, schema rejection, deduplication on the operation key, and the Unknown path for an outside effect Core cannot confirm.

Caution

Same-org Apex is trusted. Core does not sandbox it. Review extension classes, and the classes they call, before you deploy them.