[KevinAndrewDong]

Link to Issue or Description of Change

Problem: In opt-in Vertex progressive streaming, indexed argument paths are accumulated as numeric-key objects and can fail a real FunctionTool array parameter.

Solution: Distinguish unquoted array indexes from quoted numeric member names before JSONPath parsing, accumulate ordinary objects, and project only contiguous indexed containers when finalizing arguments.

Testing Plan

Unit Tests:

• I have added or updated unit tests for my change.
• All unit tests pass locally.

Frozen cloud evidence at f882b34ad57d24e911324dcda124499cfb726381: baseline 136 passed / 10 failed / 0 skipped; fixed 146 passed / 0 failed / 0 skipped. The 18 new cases are included in 146; independent reruns repeat those cases and are not additional coverage. Counts from other fixes are not added.

Fresh Mac validation (Node 22.23.2, one worker, same scoped files): unmodified production source 136 passed / 10 failed / 0 skipped; this fix 146 passed / 0 failed / 0 skipped. The expected failures occur only in the supplied new regression files; no test-name filter was used.

Scoped Mac command:

CI=1 ./node_modules/.bin/vitest run --project unit:core core/test/models/progressive_array_arguments_test.ts core/test/utils/streaming_utils_test.ts core/test/models/google_llm_test.ts core/test/features/feature_registry_test.ts core/test/tools/function_tool_test.ts --maxWorkers=1

Mac core build, workspace declaration preparation, root/sample type checks, changed-file ESLint/Prettier, diff/title checks and normal Husky/lint-staged commit checks passed. An independent read-only review covered these exact frozen source/test bytes. Cloud and Mac executions are separate evidence, not additive coverage.

Manual End-to-End (E2E) Tests:

Not performed in this Mac preparation. Full workspace build/suite, coverage, live provider/API, browser/manual E2E and full platform matrices are not established.

Checklist

• I have read the CONTRIBUTING.md document.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• I have manually tested my changes end-to-end.
• Any dependent changes have been merged and published in downstream modules.

Additional context

Experimental Vertex progressive mode remains default-off; this is not default Gemini API, full RFC9535 or provider integration coverage. Conflicting path forms and complete RFC9535 semantics are outside this change.

Prepared with Codex.

[Varun-S10]

Hi @KevinAndrewDong, thank you for raising the PR to fix the issue. We have reviewed the code changes and it does resolve the issue. I will escalate the PR to the team to review, thank you for your patience and understanding.
Hi @kalenkevich, could you please take a look?