Files
gitea-mcp/pkg/tool/definition.go
T
silverwind 0dc9868e2e fix: accept null tool arguments and bound HTTP resource use
Review follow-ups on the SDK migration.

An "arguments": null is what clients send for parameterless tools like get_me,
and what mcp-go accepted by returning a nil map. The new adapter rejected it
with InvalidParams, which broke those calls outright.

The /mcp endpoint took unlimited request bodies and never expired idle
sessions, so a peer that goes away without DELETE kept its session for the
process lifetime. Both are reachable before any token check, so neither can
stay unbounded; the body cap sits above the SDK default to leave room for the
base64 content create_or_update_file accepts.

Required() smuggled a bool through the property schema map and deleted it
again, colliding with the JSON Schema keyword of the same name. It now sets a
field on Property, so an object property can carry its own required list.

The tool contract fixture cost a manual regeneration step and four
hand-maintained counts on every tool change, and a snapshot freezes defects
rather than reporting them. Property assertions cover the same surface and
reject a duplicate tool name, a readOnlyHint that disagrees with the register
call, and a default that contradicts its own type or enum.

Co-Authored-By: Claude (Opus 5) <noreply@anthropic.com>
2026-08-02 19:34:40 +02:00

107 lines
2.8 KiB
Go

package tool
import "github.com/modelcontextprotocol/go-sdk/mcp"
// Property describes one property in a tool's input schema.
type Property struct {
name string
schema map[string]any
required bool
}
// PropertyOption configures one property in a tool's input schema.
type PropertyOption func(*Property)
// NewDefinition builds a tool definition without enabling SDK-side validation.
func NewDefinition(name, description string, annotations *mcp.ToolAnnotations, properties ...Property) *mcp.Tool {
inputProperties := make(map[string]any, len(properties))
required := make([]string, 0, len(properties))
for _, property := range properties {
inputProperties[property.name] = property.schema
if property.required {
required = append(required, property.name)
}
}
inputSchema := map[string]any{
"type": "object",
"properties": inputProperties,
}
if len(required) > 0 {
inputSchema["required"] = required
}
return &mcp.Tool{
Name: name,
Description: description,
Annotations: annotations,
InputSchema: inputSchema,
}
}
func String(name string, options ...PropertyOption) Property {
return newProperty(name, map[string]any{"type": "string"}, options...)
}
func Number(name string, options ...PropertyOption) Property {
return newProperty(name, map[string]any{"type": "number"}, options...)
}
func Boolean(name string, options ...PropertyOption) Property {
return newProperty(name, map[string]any{"type": "boolean"}, options...)
}
func Array(name string, options ...PropertyOption) Property {
return newProperty(name, map[string]any{"type": "array"}, options...)
}
func Object(name string, options ...PropertyOption) Property {
return newProperty(name, map[string]any{"type": "object", "properties": map[string]any{}}, options...)
}
func newProperty(name string, schema map[string]any, options ...PropertyOption) Property {
property := Property{name: name, schema: schema}
for _, option := range options {
option(&property)
}
return property
}
// Required marks the property as required on the parent schema. It is not a
// property-level keyword, so it never touches the emitted property schema.
func Required() PropertyOption {
return func(property *Property) {
property.required = true
}
}
func Description(description string) PropertyOption {
return func(property *Property) {
property.schema["description"] = description
}
}
func Enum(values ...string) PropertyOption {
return func(property *Property) {
property.schema["enum"] = values
}
}
func Default(value any) PropertyOption {
return func(property *Property) {
property.schema["default"] = value
}
}
func Minimum(value float64) PropertyOption {
return func(property *Property) {
property.schema["minimum"] = value
}
}
func Items(schema any) PropertyOption {
return func(property *Property) {
property.schema["items"] = schema
}
}