Add userPromptTransformed hook to all SDKs

[SteveSandersonMS]

Summary

• add typed userPromptTransformed hook APIs and dispatch across Node.js, Python, Go, .NET, Java, and Rust
• expose the runtime-transformed prompt and support replacing the model-facing content before persistence
• add shared replay E2E coverage for all six SDKs, focused serialization/unit coverage, and cross-language documentation

Implements SDK support for github/copilot-agent-runtime#12791. Supersedes the older Node-only approach in #1774 with the shipped hook contract.

[Copilot]

Pull request overview

Adds the userPromptTransformed hook across all six SDKs, enabling inspection and replacement of model-facing prompts before persistence.

Changes:

• Adds typed hook APIs and dispatch.
• Adds shared E2E and serialization coverage.
• Adds cross-language hook documentation.

Show a summary per file

File	Description
test/snapshots/hooks_extended/should_invoke_userprompttransformed_hook_and_modify_transformed_prompt.yaml	Adds shared replay fixture.
rust/tests/e2e/hooks_extended.rs	Adds Rust E2E coverage.
rust/src/hooks.rs	Implements the Rust hook API and dispatch.
python/e2e/test_hooks_extended_e2e.py	Adds Python E2E coverage.
python/copilot/session.py	Adds Python types and dispatch.
python/copilot/__init__.py	Exports Python hook types.
nodejs/test/e2e/hooks_extended.e2e.test.ts	Adds Node.js E2E coverage.
nodejs/src/types.ts	Defines Node.js hook types.
nodejs/src/session.ts	Dispatches the Node.js hook.
nodejs/src/index.ts	Exports Node.js hook types.
java/src/test/java/com/github/copilot/SessionHandlerTest.java	Tests Java dispatch.
java/src/test/java/com/github/copilot/HooksTest.java	Adds Java E2E coverage.
java/src/main/java/com/github/copilot/rpc/UserPromptTransformedHookOutput.java	Defines Java hook output.
java/src/main/java/com/github/copilot/rpc/UserPromptTransformedHookInput.java	Defines Java hook input.
java/src/main/java/com/github/copilot/rpc/UserPromptTransformedHandler.java	Defines Java handler API.
java/src/main/java/com/github/copilot/rpc/SessionHooks.java	Registers the Java handler.
java/src/main/java/com/github/copilot/CopilotSession.java	Dispatches the Java hook.
go/types.go	Defines Go hook types.
go/types_test.go	Tests empty replacement serialization.
go/session.go	Dispatches the Go hook.
go/internal/e2e/hooks_extended_e2e_test.go	Adds Go E2E coverage.
go/client.go	Registers Go hooks for create and resume.
dotnet/test/E2E/HookLifecycleAndOutputE2ETests.cs	Adds .NET E2E coverage.
dotnet/src/Types.cs	Defines .NET hook APIs.
dotnet/src/Session.cs	Dispatches and serializes the .NET hook.
dotnet/src/Client.cs	Registers .NET hooks for create and resume.
docs/README.md	Links the new hook guide.
docs/hooks/user-prompt-transformed.md	Documents the hook across languages.
docs/hooks/README.md	Adds the hook to the documentation index.
docs/hooks/hooks-overview.md	Adds the hook to the API overview.
docs/features/hooks.md	Updates lifecycle and reference documentation.

Review details

Suppressed comments (4)

docs/hooks/user-prompt-transformed.md:39

• The docs validator extracts this Python block and type-checks it as a standalone file, where client and redact are undefined. Mark the conceptual snippet as skipped (or provide hidden validation scaffolding).

```python

docs/hooks/user-prompt-transformed.md:54

• This block is compiled standalone by docs validation, but it has no imports or declarations for client, ctx, and redact, so validation fails. Mark the conceptual snippet as skipped (or provide hidden compilable scaffolding).

```go

docs/hooks/user-prompt-transformed.md:71

• Docs validation compiles this C# block independently; client and Redact are not declared, so the new article fails validation. Mark the conceptual snippet as skipped (or add hidden compilable scaffolding).

```csharp

docs/hooks/user-prompt-transformed.md:90

• The Java docs validator wraps and compiles this block, but no redact method is defined. Mark the conceptual snippet as skipped (or add hidden compilable scaffolding) to keep docs validation passing.

```java

• Files reviewed: 31/31 changed files
• Comments generated: 7
• Review effort level: Balanced

[Copilot]

Review details

Suppressed comments (2)

docs/hooks/user-prompt-transformed.md:108

• This tab defines MyHooks but never installs it on a session, so the documented callback will not run. Add session creation with with_hooks(...) to cover the same registration flow shown by the other language tabs.

#[async_trait]
impl SessionHooks for MyHooks {

docs/hooks/user-prompt-transformed.md:98

• Unlike the other language tabs, this snippet only constructs a SessionHooks value and never attaches it to a session, so copying it does not register the hook. Create the session with that hooks value so this tab demonstrates the same operation as the other examples.

This issue also appears on line 107 of the same file.

var hooks = new SessionHooks().setOnUserPromptTransformed((input, invocation) ->
    CompletableFuture.completedFuture(
        new UserPromptTransformedHookOutput(redact(input.transformedPrompt()))));

• Files reviewed: 32/32 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[Copilot]

Review details

Suppressed comments (1)

go/internal/e2e/hooks_extended_e2e_test.go:84

• The hook callback is executed on a separate goroutine (go/internal/jsonrpc2/jsonrpc2.go:450-472), but this new test appends to and later reads inputs without synchronization. This can trigger a data race under go test -race; protect both the callback write and the assertions with the mutex pattern used by the surrounding hook tests, or pass the input through a channel.

		var inputs []copilot.UserPromptTransformedHookInput
		session, err := client.CreateSession(t.Context(), &copilot.SessionConfig{
			OnPermissionRequest: copilot.PermissionHandler.ApproveAll,
			Hooks: &copilot.SessionHooks{
				OnUserPromptTransformed: func(input copilot.UserPromptTransformedHookInput, invocation copilot.HookInvocation) (*copilot.UserPromptTransformedHookOutput, error) {
					inputs = append(inputs, input)

• Files reviewed: 32/32 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[github-actions]

Cross-SDK Consistency Review ✅

This PR adds the onUserPromptTransformed / on_user_prompt_transformed / OnUserPromptTransformed hook to all six SDK implementations:

SDK	Files Modified	Status
Node.js/TypeScript	nodejs/src/types.ts, session.ts, index.ts	✅
Python	python/copilot/session.py, __init__.py	✅
Go	go/types.go, session.go, client.go	✅
.NET	dotnet/src/Types.cs, Session.cs, Client.cs	✅
Java	CopilotSession.java, SessionHooks.java + 3 new files	✅
Rust	rust/src/hooks.rs	✅

The API surface is consistent across all languages:

• Input fields: sessionId, timestamp, cwd/workingDirectory, prompt, transformedPrompt — all present in every SDK
• Output: modifiedTransformedPrompt optional field in all SDKs
• Naming: follows each language's conventions (camelCase for TS/Java, snake_case for Python/Rust, PascalCase for .NET/Go exports)
• E2E tests: added in Node.js, Python, Go, .NET, and Java

No cross-SDK consistency issues found. 🎉

Generated by SDK Consistency Review Agent for #2254 · sonnet46 20.7 AIC · ⌖ 5.42 AIC · ⊞ 6.6K · ◷

[Copilot]

Review details

• Files reviewed: 32/32 changed files
• Comments generated: 0 new
• Review effort level: Balanced