MCP API glossary
What MCP tool annotations tell clients about a tool. Select an annotation or full API badge to open its definition here.
The signature and entry documentation describe the API’s behavior, including its calling conventions, storage and runtime checks.
MCP tool annotations#
These are server-supplied hints, not enforced guarantees. Clients must not base tool-use decisions on annotations from untrusted servers.
readOnlyHint#
True indicates that the tool leaves its environment unchanged.
Defaults to false when omitted.
References: MCP ToolAnnotations .
destructiveHint#
True indicates potentially destructive changes; false indicates additive changes only.
Defaults to true. Meaningful only when readOnlyHint is false.
References: MCP ToolAnnotations .
idempotentHint#
True indicates that repeating a call with identical arguments adds no further effects.
Defaults to false. Meaningful only when readOnlyHint is false. It does not promise identical responses.
References: MCP ToolAnnotations .
openWorldHint#
True indicates possible interaction with external entities; false indicates a closed interaction domain.
Defaults to true. This describes the interaction domain, not whether the tool writes data.
References: MCP ToolAnnotations .
title#
A display title for the tool.
The tool’s top-level title takes precedence, followed by annotations.title, then name.
References: MCP ToolAnnotations .
Symbol kinds#
Kinds identify declarations in the Ruby API reference.
module#
A Ruby namespace that can also supply instance methods as a mixin.
References: Ruby modules .
class#
A Ruby object type defining instance behavior and inheriting from a superclass.
References: Ruby classes .
method#
A Ruby operation called on a receiver, usually declared with def.
Instance methods act on instances; singleton methods act on a particular object, including a class object.
References: Ruby methods .
typealias#
An RBS type alias used to describe Ruby values for tooling. It does not define a runtime class.
References: RBS type aliases .
Modifiers#
Modifiers add information about calling, implementing, or accessing a declaration. Their precise effect follows the language and the signature.
static#
A Ruby class-level or module-level singleton method, called on that object.
References: Ruby singleton methods .
Package context#
Package labels identify where an API is supplied.
package#
The Ruby gem supplying this API. Gem names identify distributions; require loads Ruby files.
References: Ruby gems .