Python: [Bug]: Workflow timings in DevUI are incorrect

[cecheta]

Description

The workflow timings shown when running a workflow in DevUI are incorrect.

Code Sample

1. Run the sample python/samples/02-agents/devui/in_memory_mode.py
2. Run the "Text Transformer" workflow

Although the workflow finishes almost instantly, the workflow timings suggest that the second step starts 3 seconds after the first.

Error Messages / Stack Traces

Package Versions

agent-framework-core: 1.2.1, agent-framework-devui: 1.0.0b260428

Python Version

3.13.11

Additional Context

No response

[github-actions]

🤖 Automated triage reproduction notes (agent-authored — trust but verify)

Agent analysis

Repro: CustomResponseOutputItemAddedEvent and CustomResponseOutputItemDoneEvent in packages/devui/agent_framework_devui/models/_openai_custom.py (lines 56-79) lack a created_at field, and the frontend workflow-view.tsx (lines 994-1009) assigns _uiTimestamp using Math.max(baseTimestamp, lastTimestamp + 1) with second precision, forcing minimum 1-second gaps between events. Minimal repro: run mapper.convert_event() for executor_invoked/executor_completed events and assert the results have no created_at attribute. Fix requires either adding created_at to custom event models and populating in the mapper, or changing the frontend uniqueTimestamp logic to use millisecond precision without forced +1s gaps.

• Failing test: python/packages/devui/tests/devui/test_workflow_timings_bug.py
• Files examined: python/packages/devui/agent_framework_devui/_mapper.py, python/packages/devui/agent_framework_devui/models/_openai_custom.py, python/packages/devui/frontend/src/components/features/workflow/workflow-view.tsx, python/packages/devui/frontend/src/stores/devuiStore.ts, python/packages/devui/frontend/src/components/features/workflow/execution-timeline.tsx, python/packages/devui/tests/devui/conftest.py
• Tests run: tests/devui/test_workflow_timings_bug.py::test_workflow_executor_events_lack_created_at (FAIL), tests/devui/test_workflow_timings_bug.py::test_rapid_workflow_events_have_no_top_level_timestamps (PASS)
• Reported version: agent-framework-devui 1.0.0b260428
• Current version: 1.0.0b260429