fix(adk): validate ask_user questions

[erauner12]

Summary

Validate built-in ask_user inputs in both Go and Python ADK runtimes on release/v0.10.x before confirmation handling.

Fixes #2468.

Problem

Both implementations accepted an empty questions list and entries whose question text was empty or whitespace-only. Those invalid calls could pause a task without presenting a usable question.

An invalid model tool call should return an error the model can correct; it should not create an unanswerable input-required interaction.

Change

Both runtimes now:

• require at least one question;
• require nonblank question text for every entry;
• reject invalid input before requesting confirmation;
• tell the model to provide at least one question; and
• preserve existing pending and confirmed behavior for valid questions.

Runtime validation remains authoritative and does not depend on a provider enforcing a generated schema.

Tests

Go:

• go test ./adk/pkg/tools
• go test -race ./adk/pkg/tools

Python:

• uv run pytest packages/kagent-adk/tests/unittests/test_ask_user_tool.py packages/kagent-adk/tests/unittests/test_hitl.py -q
• Ruff checks on the touched Python files

Coverage verifies empty-list rejection, blank-text rejection, no confirmation call for invalid input, and unchanged valid pending/confirmed behavior in both runtimes.

Validation

An independent A2A client against a compatible v0.10 deployment completed a valid structured-question round trip: one nonblank question was returned, a later process answered the retained interaction, and the same task reached terminal completion without resending the original request.

This PR changes only built-in ask_user validation; it does not change identity propagation, persistence, or A2A transport formats.

[Copilot]

Pull request overview

This PR tightens validation for the built-in ask_user tool in both the Go and Python ADK runtimes to prevent creating unusable HITL interactions (e.g., empty questions or whitespace-only question text), aligning behavior with the intent of returning correctable tool-call errors instead of pausing execution without a usable prompt.

Changes:

• Add runtime validation to require at least one question and require each question’s text to be non-blank (Go + Python).
• Ensure invalid inputs fail fast (before calling the confirmation mechanism), while preserving pending/confirmed behavior for valid inputs.
• Add focused unit tests in both languages covering empty/blank rejection and confirmation-call behavior.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
python/packages/kagent-adk/src/kagent/adk/tools/ask_user_tool.py	Adds validation for empty/blank questions and ensures confirmation is only requested for valid inputs.
python/packages/kagent-adk/tests/unittests/test_ask_user_tool.py	Adds async tests ensuring invalid inputs error without confirmation and valid flows remain unchanged.
go/adk/pkg/tools/ask_user.go	Adds input validation prior to confirmation request for empty/blank questions.
go/adk/pkg/tools/ask_user_test.go	Adds Go unit tests asserting invalid inputs don’t request confirmation and valid flows behave as expected.

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[erauner12]

Forward-port note

This validation fix is independent of #2483–#2485. A main-oriented implementation is available in erauner12#14; its production behavior is equivalent to this PR. A forward-port should retain the provider-independent runtime guards and valid pending/confirmed behavior while adapting tests to current main APIs if they have moved.

[erauner12]

Thanks for the review!

[erauner12]

CI update

The only remaining required check is Playwright E2E, failing on the unrelated missing-session UI assertion in chat-errors.spec.ts. This PR changes only the Go and Python ask_user implementations; all Go, Python, UI unit, build, upgrade, and other E2E checks passed.

The current release/v0.10.x run passed this same Playwright test, while another PR based on the same release tip failed a different Playwright CRUD case. That points to a test-environment/harness flake rather than an ask_user regression.

Next step is to rerun the failed Playwright job once. GitHub does not permit the PR author to rerun this upstream workflow, so a maintainer will need to select Re-run failed jobs. If the same failure reproduces, I’ll inspect the uploaded trace/screenshot before proposing any change; no code change is warranted from this result alone.

@supreme-gg-gg could you take a look?