Method handleGetSchema

backend/api/mcp/tool_schema.go:233–275

(ctx context.Context, req *mcp.CallToolRequest, input SchemaInput)

}

func (s *Server) handleGetSchema(ctx context.Context, req *mcp.CallToolRequest, input SchemaInput) (*mcp.CallToolResult, any, error) {
	if input.Database == "" {
		return nil, nil, errors.New("database is required")
	}

	include, err := resolveIncludeLevel(input)
	if err != nil {
		return nil, nil, err
	}

	resolved, resolveResult := s.resolveSchemaTarget(ctx, req, input)
	if resolveResult != nil {
		return resolveResult, nil, nil
	}

	// On engines that don't expose named schemas (MySQL, TiDB, ClickHouse, etc.),
	// drop the schema filter and note the drop. The backend applies `schema == "..."`
	// as an exact match, so passing a non-empty hint like "public" on MySQL would
	// filter out every table. Results are still returned; the note tells the caller
	// why the parameter was ignored.
	var warnings []string
	schemaHint := input.Schema
	if schemaHint != "" && !engineSupportsSchemas(resolved.engine) {
		warnings = append(warnings, fmt.Sprintf("schema parameter ignored — %s does not use named schemas", resolved.engine))
		schemaHint = ""
	}

	// Fetch metadata with server-side filter + limit.
	fetchCtx, fetchCancel := context.WithTimeout(ctx, schemaFetchTimeout)
	defer fetchCancel()

	metadata, err := s.fetchMetadata(fetchCtx, resolved.resourceName, buildMetadataFilter(schemaHint, input.Table), limitForInclude(include, input.Table))
	if err != nil {
		return formatToolError(err), nil, nil
	}

	if input.Table != "" {
		result, output := s.renderTableResult(fetchCtx, resolved, input, schemaHint, metadata, include, warnings)
		return result, output, nil
	}
	result, output := renderSchemasResult(resolved, metadata, include, warnings)
	return result, output, nil
}

// resolveIncludeLevel normalizes and validates the `include` parameter.
// When empty, it defaults to "details" if a table was requested and "summary" otherwise.