[codex] handle request_user_input in app-server test client (#29476)

## Why

`codex-app-server-test-client` previously treated
`item/tool/requestUserInput` as an unsupported server request and
terminated the connection. That made it impossible to use the client for
end-to-end testing of interactive turns: an operator could observe the
request, but could not answer it and confirm that the same turn resumed.

## What changed

- Handle `ToolRequestUserInput` server requests in the test client's
central request dispatcher.
- Render numbered terminal choices, accept exact option labels, support
free-form `Other` and text-only questions, and collect multiple answers.
- Send a protocol-native `ToolRequestUserInputResponse` and continue
streaming the active turn.
- Fail clearly when interactive input is requested without a terminal.
- Document the interactive behavior and add focused tests for option
selection, free-form answers, multiple questions, and invalid-selection
retries.

## Testing

- `just test -p codex-app-server-test-client`
- `just bazel-lock-check`
- Manually exercised the app-server flow, selected `TUI`, observed
`serverRequest/resolved`, and verified that the same turn completed with
the selected answer.

codex-rs/Cargo.lock

@@ -2136,6 +2136,7 @@ dependencies = [
  "codex-otel",
  "codex-protocol",
  "codex-utils-cli",
+ "pretty_assertions",
  "serde",
  "serde_json",
  "tokio",

codex-rs/app-server-test-client/Cargo.toml

@@ -26,3 +26,6 @@ uuid = { workspace = true, features = ["v4"] }
 
 [lib]
 doctest = false
+
+[dev-dependencies]
+pretty_assertions = { workspace = true }

codex-rs/app-server-test-client/README.md

@@ -18,6 +18,10 @@ cargo run -p codex-app-server-test-client -- \
 cargo run -p codex-app-server-test-client -- model-list
 ```
 
+`send-message` and `send-message-v2` handle `request_user_input` server requests interactively.
+When Codex asks a question, choose a numbered option (or `o` for a free-form answer when offered)
+and the client will send the response and continue streaming the same turn.
+
 ## Testing Plugin Analytics
 
 The `plugin-analytics-smoke` command exercises `plugin/installed`, plugin

codex-rs/app-server-test-client/src/lib.rs

@@ -91,6 +91,7 @@ mod loopback_responses_server;
 mod plugin_analytics_capture;
 mod plugin_analytics_mutation_smoke;
 mod plugin_analytics_smoke;
+mod request_user_input;
 
 const NOTIFICATIONS_TO_OPT_OUT: &[&str] = &[
     // v2 item deltas.
@@ -2040,6 +2041,10 @@ impl CodexClient {
             ServerRequest::FileChangeRequestApproval { request_id, params } => {
                 self.approve_file_change_request(request_id, params)?;
             }
+            ServerRequest::ToolRequestUserInput { request_id, params } => {
+                let response = request_user_input::prompt_for_answers(&params)?;
+                self.send_server_request_response(request_id, &response)?;
+            }
             other => {
                 bail!("received unsupported server request: {other:?}");
             }

codex-rs/app-server-test-client/src/request_user_input.rs

@@ -0,0 +1,148 @@
+use std::collections::HashMap;
+use std::io;
+use std::io::BufRead;
+use std::io::IsTerminal;
+use std::io::Write;
+
+use anyhow::Context;
+use anyhow::Result;
+use anyhow::bail;
+use codex_app_server_protocol::ToolRequestUserInputAnswer;
+use codex_app_server_protocol::ToolRequestUserInputParams;
+use codex_app_server_protocol::ToolRequestUserInputResponse;
+
+pub(super) fn prompt_for_answers(
+    params: &ToolRequestUserInputParams,
+) -> Result<ToolRequestUserInputResponse> {
+    let stdin = io::stdin();
+    if !stdin.is_terminal() {
+        bail!("request_user_input requires an interactive stdin terminal");
+    }
+
+    let stdout = io::stdout();
+    prompt_for_answers_with(&mut stdin.lock(), &mut stdout.lock(), params)
+}
+
+fn prompt_for_answers_with(
+    input: &mut impl BufRead,
+    output: &mut impl Write,
+    params: &ToolRequestUserInputParams,
+) -> Result<ToolRequestUserInputResponse> {
+    writeln!(
+        output,
+        "\n[request_user_input for thread {}, turn {}]",
+        params.thread_id, params.turn_id
+    )?;
+    if let Some(auto_resolution_ms) = params.auto_resolution_ms {
+        writeln!(
+            output,
+            "The app-server may auto-resolve this request after {auto_resolution_ms} ms."
+        )?;
+    }
+
+    let mut answers = HashMap::new();
+    for question in &params.questions {
+        writeln!(output, "\n{}: {}", question.header, question.question)?;
+        let options = question
+            .options
+            .as_deref()
+            .filter(|options| !options.is_empty());
+        let answer_values = if let Some(options) = options {
+            for (index, option) in options.iter().enumerate() {
+                writeln!(
+                    output,
+                    "  {}. {} - {}",
+                    index + 1,
+                    option.label,
+                    option.description
+                )?;
+            }
+            if question.is_other {
+                writeln!(output, "  o. Other (free-form)")?;
+            }
+
+            loop {
+                if question.is_other {
+                    write!(output, "Choose 1-{} or o: ", options.len())?;
+                } else {
+                    write!(output, "Choose 1-{}: ", options.len())?;
+                }
+                output.flush()?;
+
+                let mut line = String::new();
+                if input
+                    .read_line(&mut line)
+                    .context("failed to read request_user_input selection")?
+                    == 0
+                {
+                    bail!("stdin closed while waiting for request_user_input selection");
+                }
+                let selection = line.trim();
+
+                if let Ok(index) = selection.parse::<usize>()
+                    && let Some(option) = index.checked_sub(1).and_then(|index| options.get(index))
+                {
+                    break vec![option.label.clone()];
+                }
+
+                if let Some(option) = options
+                    .iter()
+                    .find(|option| option.label.eq_ignore_ascii_case(selection))
+                {
+                    break vec![option.label.clone()];
+                }
+
+                if question.is_other && selection.eq_ignore_ascii_case("o") {
+                    write!(output, "Other: ")?;
+                    output.flush()?;
+                    line.clear();
+                    if input
+                        .read_line(&mut line)
+                        .context("failed to read request_user_input free-form answer")?
+                        == 0
+                    {
+                        bail!("stdin closed while waiting for request_user_input free-form answer");
+                    }
+                    let answer = line.trim();
+                    if !answer.is_empty() {
+                        break vec![format!("user_note: {answer}")];
+                    }
+                }
+
+                writeln!(output, "Invalid selection; try again.")?;
+            }
+        } else {
+            loop {
+                write!(output, "Answer: ")?;
+                output.flush()?;
+
+                let mut line = String::new();
+                if input
+                    .read_line(&mut line)
+                    .context("failed to read request_user_input answer")?
+                    == 0
+                {
+                    bail!("stdin closed while waiting for request_user_input answer");
+                }
+                let answer = line.trim();
+                if !answer.is_empty() {
+                    break vec![format!("user_note: {answer}")];
+                }
+                writeln!(output, "Answer cannot be empty; try again.")?;
+            }
+        };
+
+        answers.insert(
+            question.id.clone(),
+            ToolRequestUserInputAnswer {
+                answers: answer_values,
+            },
+        );
+    }
+
+    Ok(ToolRequestUserInputResponse { answers })
+}
+
+#[cfg(test)]
+#[path = "request_user_input_tests.rs"]
+mod tests;

codex-rs/app-server-test-client/src/request_user_input_tests.rs

@@ -0,0 +1,125 @@
+use std::collections::HashMap;
+use std::io::Cursor;
+
+use codex_app_server_protocol::ToolRequestUserInputAnswer;
+use codex_app_server_protocol::ToolRequestUserInputOption;
+use codex_app_server_protocol::ToolRequestUserInputParams;
+use codex_app_server_protocol::ToolRequestUserInputQuestion;
+use codex_app_server_protocol::ToolRequestUserInputResponse;
+use pretty_assertions::assert_eq;
+
+use super::prompt_for_answers_with;
+
+#[test]
+fn collects_option_and_free_form_answers() {
+    let params = ToolRequestUserInputParams {
+        thread_id: "thread-1".to_string(),
+        turn_id: "turn-1".to_string(),
+        item_id: "item-1".to_string(),
+        questions: vec![
+            ToolRequestUserInputQuestion {
+                id: "target".to_string(),
+                header: "Target".to_string(),
+                question: "Which target?".to_string(),
+                is_other: true,
+                is_secret: false,
+                options: Some(vec![
+                    ToolRequestUserInputOption {
+                        label: "Core".to_string(),
+                        description: "Inspect core".to_string(),
+                    },
+                    ToolRequestUserInputOption {
+                        label: "TUI".to_string(),
+                        description: "Inspect TUI".to_string(),
+                    },
+                ]),
+            },
+            ToolRequestUserInputQuestion {
+                id: "details".to_string(),
+                header: "Details".to_string(),
+                question: "Anything else?".to_string(),
+                is_other: true,
+                is_secret: false,
+                options: None,
+            },
+        ],
+        auto_resolution_ms: Some(60_000),
+    };
+    let mut input = Cursor::new(b"2\ninclude snapshots\n");
+    let mut output = Vec::new();
+
+    let response = prompt_for_answers_with(&mut input, &mut output, &params).unwrap();
+
+    assert_eq!(
+        response,
+        ToolRequestUserInputResponse {
+            answers: HashMap::from([
+                (
+                    "target".to_string(),
+                    ToolRequestUserInputAnswer {
+                        answers: vec!["TUI".to_string()],
+                    },
+                ),
+                (
+                    "details".to_string(),
+                    ToolRequestUserInputAnswer {
+                        answers: vec!["user_note: include snapshots".to_string()],
+                    },
+                ),
+            ]),
+        }
+    );
+    assert_eq!(
+        String::from_utf8(output).unwrap(),
+        concat!(
+            "\n[request_user_input for thread thread-1, turn turn-1]\n",
+            "The app-server may auto-resolve this request after 60000 ms.\n",
+            "\nTarget: Which target?\n",
+            "  1. Core - Inspect core\n",
+            "  2. TUI - Inspect TUI\n",
+            "  o. Other (free-form)\n",
+            "Choose 1-2 or o: ",
+            "\nDetails: Anything else?\n",
+            "Answer: ",
+        )
+    );
+}
+
+#[test]
+fn retries_invalid_selection_and_collects_other_answer() {
+    let params = ToolRequestUserInputParams {
+        thread_id: "thread-1".to_string(),
+        turn_id: "turn-1".to_string(),
+        item_id: "item-1".to_string(),
+        questions: vec![ToolRequestUserInputQuestion {
+            id: "target".to_string(),
+            header: "Target".to_string(),
+            question: "Which target?".to_string(),
+            is_other: true,
+            is_secret: false,
+            options: Some(vec![ToolRequestUserInputOption {
+                label: "Core".to_string(),
+                description: "Inspect core".to_string(),
+            }]),
+        }],
+        auto_resolution_ms: None,
+    };
+    let mut input = Cursor::new(b"9\no\nSDK wrapper\n");
+    let mut output = Vec::new();
+
+    let response = prompt_for_answers_with(&mut input, &mut output, &params).unwrap();
+
+    assert_eq!(
+        response,
+        ToolRequestUserInputResponse {
+            answers: HashMap::from([(
+                "target".to_string(),
+                ToolRequestUserInputAnswer {
+                    answers: vec!["user_note: SDK wrapper".to_string()],
+                },
+            )]),
+        }
+    );
+    let output = String::from_utf8(output).unwrap();
+    assert!(output.contains("Invalid selection; try again."));
+}