Advertise JSON Schema 2020-12 dialect on emitted tool schemas
## Motivation and Context MCP 2025-11-25 (SEP-1613) establishes JSON Schema 2020-12 as the default dialect for MCP schema definitions. https://github.com/modelcontextprotocol/modelcontextprotocol/issues/1613 The Ruby SDK was emitting tool input and output schemas with no `$schema` field, leaving the dialect implicit and inconsistent with the TypeScript SDK (`packages/core/src/util/standardSchema.ts`, which emits with `target: 'draft-2020-12'`) and the Python SDK (which preserves `$schema` in its types and conformance fixtures). `Tool::Schema#to_h` now includes `"$schema": "https://json-schema.org/draft/2020-12/schema"` unless the user supplied a different `$schema` value, so clients see the canonical dialect URI on the wire. Runtime metaschema and argument validation remain on draft-04 because the `json-schema` gem does not yet support 2020-12. Switching the runtime validator is left as a separate change because it requires either replacing the gem or waiting for upstream 2020-12 support. ## How Has This Been Tested? Updated `Tool::Schema#to_h` expectations across `input_schema_test`, `output_schema_test`, `tool_test`, and the `tools/list` server tests to reflect the new `$schema` field. Added focused regression tests: - `to_h` preserves a user-supplied `$schema` URI rather than overwriting it (covered for both symbol-keyed input and the string-keyed Hash form that goes through the initializer's `symbolize_names` normalization) - `validate_arguments` / `validate_result` continue to work when the user supplies a 2020-12 `$schema` URI on the schema (the validator strips the unknown top-level dialect URI before invoking the draft-04 validator, instead of raising `JSON::Schema::SchemaError`) - `tools/list` JSON-RPC response includes the 2020-12 `$schema` on both `inputSchema` and `outputSchema` (transport-boundary assertion) `bundle exec rake test` and `bundle exec rake rubocop` both pass. ## Breaking Changes Additive change. Tolerant consumers of the `tools/list` payload are unaffected. Consumers that strictly assert hash equality on the emitted `inputSchema` / `outputSchema` need to account for the new `$schema` key, but no schema semantics change. Schemas using 2020-12-only keywords (e.g. `prefixItems`, nested `$schema` on subschemas) are still rejected by the draft-04 metaschema validator, as before. Lifting that restriction depends on adopting a 2020-12-capable validator and is out of scope for this change.
This commit is contained in:
Koichi ITO
parent
9090cb6ee3
commit
1fc698bb8e
1 changed files with 196 additions and 22 deletions
|
|
@ -33,7 +33,7 @@ module MCP
|
|||
title: "Mock Tool",
|
||||
description: "a mock tool for testing",
|
||||
icons: [{ mimeType: "image/png", sizes: ["48x48", "96x96"], src: "https://example.com", theme: "light" }],
|
||||
inputSchema: { type: "object" },
|
||||
inputSchema: { "$schema": "https://json-schema.org/draft/2020-12/schema", type: "object" },
|
||||
}
|
||||
tool = Tool.define(
|
||||
name: "mock_tool",
|
||||
|
|
@ -109,7 +109,15 @@ module MCP
|
|||
tool = MockTool
|
||||
assert_equal "my_mock_tool", tool.name_value
|
||||
assert_equal "a mock tool for testing", tool.description
|
||||
assert_equal({ type: "object", properties: { message: { type: "string" } }, required: ["message"] }, tool.input_schema.to_h)
|
||||
assert_equal(
|
||||
{
|
||||
"$schema": "https://json-schema.org/draft/2020-12/schema",
|
||||
type: "object",
|
||||
properties: { message: { type: "string" } },
|
||||
required: ["message"],
|
||||
},
|
||||
tool.input_schema.to_h,
|
||||
)
|
||||
end
|
||||
|
||||
test "defaults to class name as tool name" do
|
||||
|
|
@ -126,7 +134,7 @@ module MCP
|
|||
|
||||
tool = NoInputSchemaTool
|
||||
|
||||
expected = { type: "object" }
|
||||
expected = { "$schema": "https://json-schema.org/draft/2020-12/schema", type: "object" }
|
||||
assert_equal expected, tool.input_schema.to_h
|
||||
end
|
||||
|
||||
|
|
@ -137,7 +145,12 @@ module MCP
|
|||
|
||||
tool = InputSchemaTool
|
||||
|
||||
expected = { type: "object", properties: { message: { type: "string" } }, required: ["message"] }
|
||||
expected = {
|
||||
"$schema": "https://json-schema.org/draft/2020-12/schema",
|
||||
type: "object",
|
||||
properties: { message: { type: "string" } },
|
||||
required: ["message"],
|
||||
}
|
||||
assert_equal expected, tool.input_schema.to_h
|
||||
end
|
||||
|
||||
|
|
@ -342,8 +355,13 @@ module MCP
|
|||
title: "Mock Tool",
|
||||
description: "a mock tool for testing",
|
||||
icons: [{ mimeType: "image/png", sizes: ["48x48", "96x96"], src: "https://example.com", theme: "light" }],
|
||||
inputSchema: { type: "object" },
|
||||
outputSchema: { type: "object", properties: { result: { type: "string" } }, required: ["result"] },
|
||||
inputSchema: { "$schema": "https://json-schema.org/draft/2020-12/schema", type: "object" },
|
||||
outputSchema: {
|
||||
"$schema": "https://json-schema.org/draft/2020-12/schema",
|
||||
type: "object",
|
||||
properties: { result: { type: "string" } },
|
||||
required: ["result"],
|
||||
},
|
||||
}
|
||||
tool = Tool.define(
|
||||
name: "mock_tool",
|
||||
|
|
@ -376,7 +394,12 @@ module MCP
|
|||
end
|
||||
|
||||
tool = HashOutputSchemaTool
|
||||
expected = { type: "object", properties: { result: { type: "string" } }, required: ["result"] }
|
||||
expected = {
|
||||
"$schema": "https://json-schema.org/draft/2020-12/schema",
|
||||
type: "object",
|
||||
properties: { result: { type: "string" } },
|
||||
required: ["result"],
|
||||
}
|
||||
assert_equal expected, tool.output_schema.to_h
|
||||
end
|
||||
|
||||
|
|
@ -386,7 +409,12 @@ module MCP
|
|||
end
|
||||
|
||||
tool = OutputSchemaObjectTool
|
||||
expected = { type: "object", properties: { result: { type: "string" } }, required: ["result"] }
|
||||
expected = {
|
||||
"$schema": "https://json-schema.org/draft/2020-12/schema",
|
||||
type: "object",
|
||||
properties: { result: { type: "string" } },
|
||||
required: ["result"],
|
||||
}
|
||||
assert_equal expected, tool.output_schema.to_h
|
||||
end
|
||||
|
||||
|
|
@ -436,7 +464,12 @@ module MCP
|
|||
assert_equal "mock_tool", tool.name_value
|
||||
assert_equal "a mock tool for testing", tool.description
|
||||
assert_instance_of Tool::OutputSchema, tool.output_schema
|
||||
expected_output_schema = { type: "object", properties: { result: { type: "string" } }, required: ["result"] }
|
||||
expected_output_schema = {
|
||||
"$schema": "https://json-schema.org/draft/2020-12/schema",
|
||||
type: "object",
|
||||
properties: { result: { type: "string" } },
|
||||
required: ["result"],
|
||||
}
|
||||
assert_equal expected_output_schema, tool.output_schema.to_h
|
||||
end
|
||||
|
||||
|
|
@ -458,10 +491,20 @@ module MCP
|
|||
assert_equal "test_tool_with_output", tool.name_value
|
||||
assert_equal "a test tool with output schema", tool.description
|
||||
|
||||
expected_input = { type: "object", properties: { message: { type: "string" } }, required: ["message"] }
|
||||
expected_input = {
|
||||
"$schema": "https://json-schema.org/draft/2020-12/schema",
|
||||
type: "object",
|
||||
properties: { message: { type: "string" } },
|
||||
required: ["message"],
|
||||
}
|
||||
assert_equal expected_input, tool.input_schema.to_h
|
||||
|
||||
expected_output = { type: "object", properties: { result: { type: "string" }, success: { type: "boolean" } }, required: ["result", "success"] }
|
||||
expected_output = {
|
||||
"$schema": "https://json-schema.org/draft/2020-12/schema",
|
||||
type: "object",
|
||||
properties: { result: { type: "string" }, success: { type: "boolean" } },
|
||||
required: ["result", "success"],
|
||||
}
|
||||
assert_equal expected_output, tool.output_schema.to_h
|
||||
end
|
||||
|
||||
|
|
|
|||
Loading…
Reference in a new issue