flowable/flowable-engine · error · FlowableIllegalArgumentException

Invalid action: '${action}'.

Error message

Invalid action: '${action}'.

What it means

Thrown by updateCaseInstance (PUT on a case instance) when the 'action' field in the CaseInstanceUpdateRequest body is neither 'claim' nor 'unclaim'. Flowable only supports these two actions on this endpoint; anything else is rejected as an invalid argument via FlowableIllegalArgumentException.

Source

Thrown at modules/flowable-cmmn-rest/src/main/java/org/flowable/cmmn/rest/service/api/runtime/caze/CaseInstanceResource.java:111

        CaseInstance caseInstance = getCaseInstanceFromRequestWithoutAccessCheck(caseInstanceId);

        if (StringUtils.isNotEmpty(updateRequest.getAction())) {

            if (restApiInterceptor != null) {
                restApiInterceptor.doCaseInstanceAction(caseInstance, updateRequest);
            }

            if (RestActionRequest.EVALUATE_CRITERIA.equals(updateRequest.getAction())) {
                runtimeService.evaluateCriteria(caseInstance.getId());

            } else if (CaseInstanceUpdateRequest.ACTION_CLAIM.equals(updateRequest.getAction())) {
                runtimeService.claimCaseInstance(caseInstanceId, updateRequest.getAssignee());

            } else if (CaseInstanceUpdateRequest.ACTION_UNCLAIM.equals(updateRequest.getAction())) {
                runtimeService.unclaimCaseInstance(caseInstanceId);

            } else {
                throw new FlowableIllegalArgumentException("Invalid action: '" + updateRequest.getAction() + "'.");
            }

        } else { // regular update

            if (restApiInterceptor != null) {
                restApiInterceptor.updateCaseInstance(caseInstance, updateRequest);
            }

            boolean hasUpdates = false;
            CaseInstanceUpdateBuilder updateBuilder = runtimeService.createCaseInstanceUpdateBuilder(caseInstanceId);

            if (updateRequest.getName() != null) {
                updateBuilder.name(updateRequest.getName());
                hasUpdates = true;
            }
            if (updateRequest.getBusinessKey() != null) {
                updateBuilder.businessKey(updateRequest.getBusinessKey());
                hasUpdates = true;

View on GitHub (pinned to d6d39ce1c6)

Solutions

1. Set 'action' to exactly "claim" or "unclaim" in the request body.
2. To claim, include the "assignee" field alongside action=claim; for unclaim, no assignee is needed.
3. Remove the 'action' field entirely if you intend a regular update handled by restApiInterceptor instead of a claim/unclaim.
4. Check the Flowable REST API docs for your version to confirm the supported action values.

Example fix

// before
PUT /cmmn-runtime/case-instances/case1
{"action":"activate"}
// after
PUT /cmmn-runtime/case-instances/case1
{"action":"claim","assignee":"johnDoe"}

const VALID_ACTIONS = ['claim', 'unclaim'];
if (body.action && !VALID_ACTIONS.includes(body.action)) {
  throw new Error(`Invalid action '${body.action}'; use 'claim' or 'unclaim'`);
}
if (body.action === 'claim' && !body.assignee) {
  throw new Error('claim requires an assignee');
}

function isCaseAction(a) {
  return typeof a === 'string' && ['claim', 'unclaim'].includes(a);
}

try {
  await updateCaseInstance(caseId, body);
} catch (e) {
  if (e.status === 400) { /* invalid action: fix body before retry */ }
  else throw e;
}

When it happens

Trigger: PUT /cmmn-runtime/case-instances/{caseInstanceId} with a JSON body whose 'action' property is an unsupported string (e.g. 'suspend', 'activate', 'complete', or a typo like 'claime'), while no assignee-based regular update path applies.

Common situations: Copy-pasting request bodies from the process (BPMN) REST API which supports more actions; typos or wrong casing in the action string; clients sending action values not valid for CMMN case instances; API version drift where an action existed in a different product/endpoint.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• Invalid action, only 'execute' is supported.
• Invalid action, only 'execute' is supported.
• Variable operation is missing for variable:
• Variable value is missing for variable:
• Value-only query (without a variable-name) is not supported

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/decb9a892f4a2beb. Report an issue: GitHub.