User prompt transformed hook

Use it when you need to inspect or replace the exact model-facing prompt. The prompt input contains the user prompt after any userPromptSubmitted hooks have run, while transformedPrompt also contains runtime-generated context such as <current_datetime>.

Input and output

Input field	Type	Description
`sessionId`	string	Runtime session ID
`timestamp`	date/time	Time the hook was invoked
`cwd` / `workingDirectory`	string	Current working directory
`prompt`	string	Prompt after `userPromptSubmitted` hooks
`transformedPrompt`	string	Model-facing prompt after runtime transformations

Return no value to leave the transformed prompt unchanged. Return modifiedTransformedPrompt to replace the content that is stored in session history and sent to the model.

Examples

Code languages navigation

TypeScript

const session = await client.createSession({
  hooks: {
    onUserPromptTransformed: async (input) => ({
      modifiedTransformedPrompt: redact(input.transformedPrompt),
    }),
  },
});

Python

session = await client.create_session(
    hooks={
        "on_user_prompt_transformed": lambda input_data, invocation: {
            "modifiedTransformedPrompt": redact(input_data["transformedPrompt"])
        }
    }
)

session, err := client.CreateSession(ctx, &copilot.SessionConfig{
	Hooks: &copilot.SessionHooks{
		OnUserPromptTransformed: func(input copilot.UserPromptTransformedHookInput, invocation copilot.HookInvocation) (*copilot.UserPromptTransformedHookOutput, error) {
			return &copilot.UserPromptTransformedHookOutput{
				ModifiedTransformedPrompt: copilot.String(redact(input.TransformedPrompt)),
			}, nil
		},
	},
})

.NET

var session = await client.CreateSessionAsync(new SessionConfig
{
    Hooks = new SessionHooks
    {
        OnUserPromptTransformed = (input, invocation) =>
            Task.FromResult<UserPromptTransformedHookOutput?>(new()
            {
                ModifiedTransformedPrompt = Redact(input.TransformedPrompt),
            }),
    },
});

Java

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

var session = client.createSession(new SessionConfig().setHooks(hooks)).get();

Rust

#[async_trait]
impl SessionHooks for MyHooks {
    async fn on_user_prompt_transformed(
        &self,
        input: UserPromptTransformedInput,
        _ctx: HookContext,
    ) -> Option<UserPromptTransformedOutput> {
        Some(UserPromptTransformedOutput {
            modified_transformed_prompt: Some(redact(&input.transformed_prompt)),
        })
    }
}

let session = client
    .create_session(SessionConfig::default().with_hooks(Arc::new(MyHooks)))
    .await?;

The replacement is persisted as the user message content, so resumed sessions replay the modified content unchanged.

In this article

Input and output

Examples

Code languages navigation