karatelabs/karate · error · RuntimeException

karate.call() is not available in this context

Error message

karate.call() is not available in this context

What it means

karate.call() must run against a ScenarioRuntime: it delegates to rt.executeJsCall(path, arg) to invoke another feature/script. The bridge's getRuntime() returned null, meaning this karate object was created without a runtime binding, so calling another feature is impossible. The argument check comes after this check, so a context-less runtime is reported first.

Solutions

  1. Ensure karate.call() is only used inside a Scenario (or Background) where a ScenarioRuntime is active.
  2. In mock contexts, implement the behavior directly in JS or use mock-specific request/response handling instead of calling features.
  3. If the bridge should have a runtime, verify how the karate object was obtained — it must come from within scenario execution, not a detached engine.

Example fix

// before (in mock handler JS)
var result = karate.call('helpers.feature');
// after: run the call inside a scenario, or inline the logic
var result = { /* computed directly in JS */ };
Defensive patterns

Strategy: type-guard

Validate before calling

// only call features from scenario-executing JS; do not call from mock handler JS
if (typeof karate.call !== 'function') throw new Error('karate.call unavailable');

Type guard

function canCallFeatures() {
  try { karate.call; return true; } catch (e) { return false; }
}
// and structurally: only invoke karate.call inside Scenario/Background JS, never in mock server scripts

Try / catch

var result;
try {
  result = karate.call('classpath:x.feature');
} catch (e) {
  if (String(e.message).includes('not available in this context')) {
    throw new Error('karate.call must run inside a Scenario, not a mock/standalone JS context');
  }
  throw e;
}

Prevention

When it happens

Trigger: Invoking karate.call('other.feature') (with any arguments, even none) from a JS context where the karate bridge has no ScenarioRuntime — e.g. inside a mock server handler or a standalone JS engine.

Common situations: Mock contexts responding to requests by trying to call another feature; utility JS evaluated outside scenario execution; hooks that run before/after a runtime exists.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of karatelabs/karate@a22eb90246 (2026-09-12). Data as JSON: /api/errors/e825c2b57f3fbe0e. Report an issue: GitHub.

Appendix: source

Thrown at karate-core/src/main/java/io/karatelabs/core/KarateJs.java:690

                ScenarioRuntime rt = ScenarioRuntime.currentOrNull();
                if (rt == null) {
                    rt = getRuntime();
                }
                if (rt == null) {
                    throw new RuntimeException("karate.match(String) is not available in this context");
                }
                String expression = args[0].toString();
                Result result = rt.getExecutor().evalMatchString(expression, null);
                return result.toMap();
            }
        };
    }

    private JavaInvokable call() {
        return args -> {
            ScenarioRuntime rt = getRuntime();
            if (rt == null) {
                throw new RuntimeException("karate.call() is not available in this context");
            }
            if (args.length == 0) {
                throw new RuntimeException("karate.call() requires at least one argument (feature path)");
            }
            // V1 compatible signatures:
            // call(path) - isolated scope
            // call(path, arg) - isolated scope with arg
            // call(sharedScope, path) - explicit scope
            // call(sharedScope, path, arg) - explicit scope with arg
            boolean sharedScope = false;
            String path;
            Object arg;
            if (args[0] instanceof Boolean) {
                sharedScope = (Boolean) args[0];
                if (args.length < 2) {
                    throw new RuntimeException("karate.call() with sharedScope requires a feature path");
                }
                path = args[1].toString();

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