Class: MCP::Tool::Schema

Inherits:
Object
  • Object
show all
Defined in:
lib/mcp/tool/schema.rb

Direct Known Subclasses

InputSchema, OutputSchema

Defined Under Namespace

Classes: ValidationCache

Constant Summary collapse

VALIDATION_CACHE = 
ValidationCache.new
JSON_SCHEMA_2020_12_URI =

JSON Schema 2020-12 is the default dialect for MCP schema definitions per MCP 2025-11-25 (SEP-1613), and SEP-2106 requires tool schemas to conform to the full 2020-12 vocabulary. Both emission and runtime validation use this dialect. Because MCP mandates 2020-12, the SDK validates against it regardless of any $schema a document embeds; for compliant schemas this is the same dialect the Python SDK's jsonschema.validate resolves to.

"https://json-schema.org/draft/2020-12/schema"
MAX_SCHEMA_DEPTH =

Resource bounds for schema compilation, mirroring the TypeScript SDK's schema bounds (SEP-2106): schemas may use the full JSON Schema 2020-12 vocabulary including composition keywords and $ref, so adversarial documents must be rejected before they can cause excessive validation cost. Only same-document references (starting with #) are accepted, so schema handling can never trigger network or file access.

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MAX_SUBSCHEMA_COUNT = 
10_000
REFERENCE_KEYWORDS =

Reference keywords whose targets the SDK refuses to dereference. Both $ref and $dynamicRef may carry an absolute URI under JSON Schema 2020-12, so a non-same-document value is an external reference.

[:"$ref", :"$dynamicRef"].freeze

Instance Method Summary collapse

Constructor Details

#initialize(schema = {}) ⇒ Schema

Returns a new instance of Schema.



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# File 'lib/mcp/tool/schema.rb', line 58

def initialize(schema = {})
  @schema = JSON.parse(JSON.dump(schema), symbolize_names: true)
  apply_default_root_type!
  validate_schema_bounds!
  validate_schema!
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/mcp/tool/schema.rb', line 65

def ==(other)
  other.is_a?(self.class) && @schema == other.instance_variable_get(:@schema)
end

#to_h ⇒ Object 



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# File 'lib/mcp/tool/schema.rb', line 69

def to_h
  return @schema if @schema.key?(:"$schema")

  { "$schema": JSON_SCHEMA_2020_12_URI }.merge(@schema)
end