mcpHeader

UDA marking a @tool parameter as mirrored into an HTTP request header.

Per the MCP draft (server/tools #x-mcp-header), a server MAY designate tool parameters to be mirrored into headers via an x-mcp-header extension property in the parameter's inputSchema. Apply this UDA directly to the parameter; the reflection layer emits the corresponding x-mcp-header property (carrying name) into the generated input schema, so that the streamable-HTTP transport can validate the Mcp-Param-<name> header against the argument value.

@safe

struct mcpHeader {

string name;

}

Members

Variables

name string name;: the header suffix, e.g. "Region" -> Mcp-Param-Region

Examples

@tool("query", "Query a region")
string query(@mcpHeader("Region") string region) { ... }