Todo 46.1 Mode Parity and Duplicate Call Safety Plan

Status: in_progress

Goal

Remove three review-confirmed sources of unsafe or unfair comparison behavior between dual_agent and chat_agent_tools.

Detect provider tool-call IDs already declared in active direct-mode history before creating a new assistant transcript or executing handlers.
Prevent duplicate IDs within a batch and across rounds from causing repeated side effects.
Execute direct-mode batches concurrently while preserving provider call order in returned tool messages.
Apply max_event_loops acceptance to dual text events as well as direct provider calls.

A duplicate provider call ID should fail the current runtime before the duplicate handler runs; do not invent a second invalid assistant/tool transcript.
Use ordinary asyncio.gather parity for this todo; bounded concurrency, conflict classes, terminal barriers, and timeout policy remain Todo 48.
Preserve visible reply streaming that occurred before a duplicate is detected.

Add RED one-shot and session tests for duplicate provider IDs across rounds; handler call count must remain one.
Add a timing/overlap RED test proving two direct async handlers start before either finishes and replies retain input order.
Add RED dual-mode tests proving events after budget exhaustion are ignored and the loop terminates.
Implement pre-execution ID validation, concurrent direct execution, and symmetric budget acceptance.
Run focused/full verification and renewed reviews.

Close Todo 46 only when both modes differ only in orchestration protocol, not duplicate safety, event budget, or handler scheduling semantics.