What causes "not enough arguments passed %s.%s idx:%d (type %T)" in wavetermdev/waveterm?

Supply all required positional arguments in webCall.Args in the method's declared order (excluding ctx/UIContext)

not enough arguments passed %s.%s idx:%d (type %T)

Error message

not enough arguments passed %s.%s idx:%d (type %T)

What it means

CallService maps the method's declared parameters (skipping context.Context and UIContext) onto the JSON args array in webCall.Args one by one. This error is returned when the method requires more positional arguments than the request supplied, i.e. argIdx ran past len(webCall.Args) while parameter idx still needed a value.

Source

Thrown at pkg/service/service.go:342

		return webErrorRtn(fmt.Errorf("invalid method: %s.%s", webCall.Service, webCall.Method))
	}
	var valueArgs []reflect.Value
	argIdx := 0
	for idx := 0; idx < method.Type().NumIn(); idx++ {
		argType := method.Type().In(idx)
		if idx == 0 && argType == contextRType {
			valueArgs = append(valueArgs, reflect.ValueOf(ctx))
			continue
		}
		if argType == uiContextRType {
			if webCall.UIContext == nil {
				return webErrorRtn(fmt.Errorf("missing UIContext for %s.%s", webCall.Service, webCall.Method))
			}
			valueArgs = append(valueArgs, reflect.ValueOf(*webCall.UIContext))
			continue
		}
		if argIdx >= len(webCall.Args) {
			return webErrorRtn(fmt.Errorf("not enough arguments passed %s.%s idx:%d (type %T)", webCall.Service, webCall.Method, idx, argType))
		}
		nativeArg, err := convertArgument(argType, webCall.Args[argIdx])
		if err != nil {
			return webErrorRtn(fmt.Errorf("cannot convert argument %s.%s type:%T idx:%d error:%v", webCall.Service, webCall.Method, argType, idx, err))
		}
		valueArgs = append(valueArgs, reflect.ValueOf(nativeArg))
		argIdx++
	}
	retValArr := method.Call(valueArgs)
	return convertReturnValues(retValArr)
}

// ValidateServiceArg validates the argument type for a service method
// does not allow interfaces (and the obvious invalid types)
// arguments + return values have special handling for wave objects
func baseValidateServiceArg(argType reflect.Type) error {
	if argType == waveObjUpdateRType {
		// has special MarshalJSON method, so it is safe

View on GitHub (pinned to a4447c1563)

Solutions

Supply all required positional arguments in webCall.Args in the method's declared order (excluding ctx/UIContext)
Regenerate/refresh the TypeScript client (tsgen) so arg counts match the backend signatures
If a parameter is genuinely optional, extend the method or pass an explicit zero value (e.g. false for bool, "" for string)
Read the idx and type in the message to see exactly which parameter (position, counting ctx) was missing

Example fix

// before
CallService(ctx, WebCallType{Service: "workspace", Method: "CreateWorkspace", Args: ["my-ws"]})
// after
CallService(ctx, WebCallType{Service: "workspace", Method: "CreateWorkspace", Args: ["my-ws", "terminal", "blue", true]})

Defensive patterns

Strategy: validation

Validate before calling

const minArgs = { CreateWorkspace: 4, UpdateWorkspace: 5, CreateWindow: 2 };
function hasEnoughArgs(service, method, args) {
  const n = minArgs[method];
  return n == null || Array.isArray(args) && args.length >= n;
}

Type guard

function argsMatchArity<N extends number>(args: unknown[], n: N): args is { length: N } & unknown[] {
  return args.length >= n;
}

Try / catch

const rtn = CallService(ctx, call);
if (rtn.Error.startsWith("not enough arguments")) {
  console.error(`arity error for ${call.Service}.${call.Method}:`, rtn.Error);
  // regenerate client / fix arg list
}

Prevention

Use the generated typed client so arity is checked at compile time
Regenerate tsgen output whenever a service method signature changes
Count args as method params minus leading ctx (and UIContext) when hand-building calls

When it happens

Trigger: Sending fewer JSON args than the service method's non-context, non-UIContext parameter count — e.g. CreateWorkspace(ctx, name, icon, color, applyDefaults) called with only 2 args, or a call using an outdated arg count after the method gained a parameter.

Common situations: Frontend/backend version skew after a service method gained a new parameter; hand-built RPC payloads in tests or scripts omitting trailing args; variadic-vs-fixed arg confusion; boolean/optional trailing parameters assumed skippable.

Related errors

AI-assisted analysis of wavetermdev/waveterm@a4447c1563 (2026-09-01). Data as JSON: /api/errors/4c21504a0b745dfb. Report an issue: GitHub.