No way to add `temp:variable` during `Runner.runAsync`

[wbyoung]

Is your feature request related to a problem? Please describe.

There's no way to inject a temporary variable into the session state at the start of an invocation. The temp: prefixed variables are filtered out.

The workarounds I've thought through (like leveraging plugins) seem over the top.

Describe the solution you'd like

Add a way for the caller access the invocation context or the session during/after the call to Runner.runAsync.

For instance:

runner.runAsync({
  // existing params
  beforeRunCallback: ({ invocationContext }) => {
    invocationContext.session.state.set('temp:var', 'value')
  },
})

Describe alternatives you've considered

This is roughly how plugins work, but plugins don't have a way to access the local scope in which runner.runAsync was called (unless a new runner is created which doesn't seem to be recommended for long running processes like API servers).

[Varun-S10]

Hi @wbyoung, Thank you for sharing this with us, we really appreciate it and will escalate it to the team. Thank you for your patience and understanding.

Hi @kalenkevich, I would like to escalate this user request to add temp:variable during Runner.runAsync.

[ScottMansfield]

This type of change normally needs more coordination internally between the different ADK languages. What would it look like with a plugin? You can override only a single plugin method if needed.

[wbyoung]

This type of change normally needs more coordination internally between the different ADK languages. What would it look like with a plugin? You can override only a single plugin method if needed.

It would probably look a bit like the example in #269. But that seems like a lot of work for something that the docs suggest (to some extent) should be possible & just work.