Studio import returns 500 on its own export when an input value is numeric

Symptom

Re-importing Studio's own export returns HTTP 500 when any action input holds a numeric value — for example max_tokens: 1024.

Reported against 26.9.0.

Root cause — confirmed in the code

studio/ryax/studio/infrastructure/packaging/packaging_import.py:234:

if workflow_action_input_value_yaml is not None:
    if workflow_action_input_value_yaml.startswith("="):

The value comes straight from the parsed YAML, so it is whatever type YAML produced. 1024 is an int, which has no .startswith, and the AttributeError surfaces as a 500. Only values that happen to be strings work.

The "=" prefix is the reference-vs-literal marker, so the check has to run on every input — it just needs to be type-safe first.

Reproduction

  1. Build a workflow with an integer static input (max_tokens: 1024).
  2. Export it from Studio.
  3. Import the file Studio just produced → HTTP 500.

Export/import is not round-trip safe, which makes this reproducible from the product's own output rather than from hand-written YAML.

Workaround in place

The demo builds workflows through the UI APIs instead of importing them.

Suggested fix

Coerce to str before the prefix test, or test isinstance(value, str) and value.startswith("=") and treat non-strings as literals. A regression test should cover int, float and bool inputs, since YAML will produce all three.

Found while migrating the CAPE demo to Ryax 26.9.0: ryax-tech/public/cape-tools/cape-agentic-infra#2 (comment 3905714558)