BidiLens: mixed-language rendering cases for DevUI and custom agent clients

[Shayan (CodeinScrubs)]

Hello — sharing a narrowly scoped UI resource for people building multilingual clients on Agent Framework.

I maintain BidiLens (MIT). It helps applications choose paragraph direction and isolate opposite-direction fragments without rewriting their stored text. The interesting boundary here is DevUI or a custom client renderer, not the Python/.NET agent runtime.

For example, an English product name at the beginning of otherwise Persian prose can make first-strong direction differ from what its author wants. Dates, inline code and punctuation bring additional cases. A left-aligned UI should still be able to display an RTL paragraph correctly.

Since DevUI is a development/testing sample, I would start with a small rendering fixture set that custom-client authors can reuse. Acceptance checks should include ordinary LTR content, explicit author overrides, RTL content in an LTR layout, preservation of logical copy text, and the final result after streaming. Raw prompts, tool arguments and traces should remain unchanged.

This is not a report of a reproduced Agent Framework defect or a request to add a backend dependency. Native direction controls can be enough. Our .NET implementation is source-level, not a published NuGet package; editor, accessibility and real-device behavior require host-specific validation.

For a concrete contribution example, our dependency-free mixed-direction message example was merged into PersianLabs. That was native documentation work, not package adoption.

If this fits your community samples, I would welcome guidance on the most useful client-side boundary for a small follow-up.