Strip Ms suffix for duration properties

[stephentoub]

Duration-formatted schema fields already map to timespan-like SDK types in Python and C#, but generated member names still exposed millisecond-oriented wire suffixes like durationMs. This keeps the wire contract unchanged while making the generated SDK surface more idiomatic for duration values.

Summary

• Strip eligible trailing Ms from duration property names in the Python and C# generators.
• Preserve original JSON field names through generated serialization metadata and dict keys.
• Regenerate Python and .NET generated outputs and update serialization coverage.

Validation

• npm --prefix .\nodejs test -- python-codegen.test.ts

[Copilot]

Pull request overview

This PR updates the Python and C# code generators to produce more idiomatic SDK member names for duration-valued schema properties by removing trailing Ms from the generated member name (while preserving the original JSON/wire property names via serialization metadata). This aligns the public SDK surface with the fact that these fields already map to timedelta/TimeSpan-like types, without changing the wire contract.

Changes:

• Python codegen: detect duration-valued properties and strip a trailing Ms from the generated Python field name (snake_case), while keeping JSON keys unchanged.
• C# codegen: apply the same Ms-stripping rule for duration-valued properties, including nullable wrappers, while keeping [JsonPropertyName("...Ms")] intact.
• Regenerate Python/.NET generated outputs and extend Node-based codegen tests to validate name stripping + JSON-name preservation.

Show a summary per file

File	Description
scripts/codegen/python.ts	Adds duration-property detection and Ms suffix stripping when computing Python field names.
scripts/codegen/csharp.ts	Adds duration-aware Ms suffix stripping for generated C# property names and improves nullable duration detection.
python/copilot/generated/session_events.py	Regenerated output reflecting renamed duration members (e.g., ttft_ms → ttft) while preserving JSON keys.
nodejs/test/python-codegen.test.ts	Adds a test covering Ms stripping behavior and JSON-name preservation (Python + C#).
dotnet/test/Unit/SessionEventSerializationTests.cs	Updates unit test to use the renamed .NET duration property.
dotnet/src/Generated/SessionEvents.cs	Regenerated session event types with Ms-less duration property names and unchanged [JsonPropertyName].
dotnet/src/Generated/Rpc.cs	Regenerated RPC types with Ms-less duration property names and unchanged [JsonPropertyName].

Copilot's findings

• Files reviewed: 4/7 changed files
• Comments generated: 1

[github-actions]

Cross-SDK Consistency Review ✅

This PR makes a well-scoped, intentional distinction across the SDK implementations:

SDK	Duration type	Ms suffix treatment	Rationale
Python	timedelta	Stripped (this PR)	Native type makes suffix redundant
.NET	TimeSpan	Stripped (this PR)	Native type makes suffix redundant
Go	float64 / int64	Retained	Raw numeric — suffix communicates the unit
Rust	f64 / i64	Retained	Raw numeric — suffix communicates the unit
Node.js	number	Retained	Raw numeric — suffix communicates the unit

The approach is consistent: only SDKs that map duration fields to a dedicated native duration type get the suffix stripped, because in those cases the type already conveys "this is a duration" and the Ms suffix becomes noise. For languages using raw numbers, durationMs vs duration is the difference between self-documenting and ambiguous.

Additional consistency checks:

• ✅ Wire format is unchanged in all SDKs — [JsonPropertyName("durationMs")] / obj.get("durationMs") preserve the original JSON names
• ✅ Edge case handled correctly: URLMs is not stripped (the char before Ms is uppercase L), consistent in both Python and C# codegen
• ✅ Test file renamed python-codegen.test.ts → session-event-codegen.test.ts to accurately reflect its coverage of both Python and C# codegen

No cross-SDK consistency issues found.

Generated by SDK Consistency Review Agent for issue #1339 · ● 618.4K · ◷