Fix C# canvas action RPC compatibility

[stephentoub]

The copilot-agent-runtime CI leg runs the latest C# SDK tests against the live runtime, and the canvas action test was failing because that runtime still dispatches the legacy canvas.action.invoke client-session method.

This keeps the canonical canvas.invokeAction registration and also registers canvas.action.invoke to the same C# canvas handler path. The C# code generator now emits that compatibility alias so regenerated RPC sources preserve the fix.

Tests:

• dotnet build dotnet\src\GitHub.Copilot.SDK.csproj --no-restore
• dotnet test dotnet\test\GitHub.Copilot.SDK.Test.csproj --filter "FullyQualifiedName~GitHub.Copilot.Test.Unit.CanvasTests" --no-restore

[Copilot]

Pull request overview

This PR restores compatibility between the .NET/C# SDK and older runtimes that still dispatch canvas action callbacks using the legacy client-session JSON-RPC method name canvas.action.invoke, by registering it as an alias of the canonical canvas.invokeAction handler path (and baking that into the C# code generator so regeneration preserves it).

Changes:

• Update the C# code generator to emit a compatibility alias registration for canvas.invokeAction → canvas.action.invoke.
• Regenerate the .NET RPC registration code to register both method names to the same canvas handler.
• Update .NET XML docs to mention the legacy method name.

Show a summary per file

File	Description
scripts/codegen/csharp.ts	Adds a helper to emit additional client-session RPC registrations for specific methods (canvas invokeAction legacy alias).
dotnet/src/Types.cs	Updates CanvasHandler XML docs to mention legacy canvas.action.invoke.
dotnet/src/Generated/Rpc.cs	Registers canvas.action.invoke to the same handler as canvas.invokeAction.
dotnet/src/Canvas.cs	Updates ICanvasHandler XML docs to mention legacy canvas.action.invoke (needs a small grammar fix).

Copilot's findings

• Files reviewed: 3/4 changed files
• Comments generated: 2

[github-actions]

Cross-SDK Consistency Review

This PR fixes a C# compatibility issue where older runtimes dispatch canvas actions via the legacy canvas.action.invoke method name instead of the canonical canvas.invokeAction. The fix registers both method names to the same handler.

Potential consistency gap: The other SDK implementations (Node.js, Python, Go, Java) only register canvas.invokeAction and do not have the equivalent canvas.action.invoke legacy alias:

• Node.js (nodejs/src/generated/rpc.ts line ~11458): connection.onRequest("canvas.invokeAction", ...) — no legacy alias
• Python (python/copilot/generated/rpc.py line ~18183): client.set_request_handler("canvas.invokeAction", ...) — no legacy alias
• Go (go/rpc/zrpc.go line ~12114): client.SetRequestHandler("canvas.invokeAction", ...) — no legacy alias
• Java: Similar pattern, no legacy alias

If the older runtime affecting C# CI is also used in CI legs for the other languages, those SDKs may have the same latent bug. It's worth checking whether the other language CI legs run against the same runtime version, and if so, applying the same compatibility alias to their codegens (scripts/codegen/typescript.ts, scripts/codegen/python.ts, scripts/codegen/go.ts, and the Java codegen).

That said, if only the C# CI leg uses the older runtime, this PR is appropriately scoped and the other SDKs are fine as-is.

Generated by SDK Consistency Review Agent for issue #1436 · ● 3.5M · ◷