siyuan-note/siyuan · error

missing method field

Error message

missing method field

What it means

Returned when the request has a valid jsonrpc field but the method field is absent (util.Optional.HasValue() is false). A JSON-RPC request without a method is invalid; notifications still require method (they just omit id).

Source

Thrown at kernel/plugin/rpc.go:119

		Params  util.Optional[any]    `json:"params"`
		ID      util.Optional[any]    `json:"id"`
	}
	request := JsonRpcRequestObject{}
	if err := decoder.Decode(&request); err != nil {
		return err
	}

	// Validate jsonrpc field
	if !request.JsonRpc.Exists {
		return fmt.Errorf("missing jsonrpc field")
	}
	if request.JsonRpc.Value != JsonRpcVersion {
		return fmt.Errorf("invalid jsonrpc version: %s", request.JsonRpc.Value)
	}

	// Validate method field
	if !request.Method.HasValue() {
		return fmt.Errorf("missing method field")
	}

	// Validate id field
	if !request.ID.Exists {
	} else if request.ID.IsNull {
	} else if _, ok := request.ID.Value.(string); ok {
	} else if _, ok := request.ID.Value.(float64); ok {
	} else {
		return fmt.Errorf("invalid id field: must be string, number, null or omitted")
	}

	r.JsonRpc = request.JsonRpc.Value
	r.Method = request.Method.Value
	r.Params = request.Params
	r.ID = request.ID
	return nil
}

View on GitHub (pinned to 251596fc0d)

Solutions

1. Always include a non-empty "method" string in the request.
2. Use a typed RPC client that forces method as a required parameter.
3. Check the field name spelling against the JSON-RPC 2.0 spec.

Example fix

// before
{ jsonrpc: '2.0', id: 1, action: 'doStuff', params: [] }

// after
{ jsonrpc: '2.0', id: 1, method: 'doStuff', params: [] }

if (typeof req.method !== 'string' || req.method.length === 0) throw new Error('method required');

function hasMethod(o: unknown): o is { method: string } { return !!o && typeof o === 'object' && typeof (o as any).method === 'string' && (o as any).method.length > 0; }

When it happens

Trigger: Client sends {"jsonrpc":"2.0","id":1,"params":[]} with no method, or a payload where method is null/omitted.

Common situations: Typo in the field name (e.g. 'action' instead of 'method'), or a generic envelope reused for results/errors that lacks method.

Related errors

• missing jsonrpc field
• invalid jsonrpc version: %s
• invalid id field: must be string, number, null or omitted
• Agent capability name and description are required
• plugin [%s] not found

AI-assisted analysis of siyuan-note/siyuan@251596fc0d (2026-08-12). Data as JSON: /api/errors/ce8ed29c464b3603. Report an issue: GitHub.