feat: add doctor command for diagnosing installs and cleaning stale daemon state (#1254)

* feat: add `doctor` command for install diagnostics and cleanup

Adds `agent-browser doctor`, a one-shot diagnostic that checks
environment, Chrome install, daemon state, config, encryption key,
providers, network reachability, and a live headless launch test.
Auto-cleans stale `.sock` / `.pid` / `.version` / `.stream` sidecar
files on every run. Destructive repairs (reinstall Chrome, purge old
state, close version-mismatched daemons, generate missing encryption
key) are gated behind `--fix`. Supports `--offline`, `--quick`, and
`--json`.

* fixes

cli/src/connection.rs

@@ -12,6 +12,11 @@ use std::time::Duration;
 #[cfg(unix)]
 use std::os::unix::net::UnixStream;
 
+#[cfg(windows)]
+use windows_sys::Win32::Foundation::CloseHandle;
+#[cfg(windows)]
+use windows_sys::Win32::System::Threading::{OpenProcess, PROCESS_QUERY_LIMITED_INFORMATION};
+
 #[derive(Serialize)]
 #[allow(dead_code)]
 pub struct Request {
@@ -144,6 +149,186 @@ pub fn cleanup_stale_files(session: &str) {
     }
 }
 
+/// Returns whether a process with the given PID is currently alive.
+///
+/// On unix, EPERM (process exists but we can't signal it) counts as alive
+/// so we don't mis-clean a live daemon owned by a different uid. Only ESRCH
+/// ("no such process") is treated as dead.
+pub fn is_pid_alive(pid: u32) -> bool {
+    #[cfg(unix)]
+    unsafe {
+        if libc::kill(pid as i32, 0) == 0 {
+            return true;
+        }
+        std::io::Error::last_os_error().raw_os_error() != Some(libc::ESRCH)
+    }
+    #[cfg(windows)]
+    unsafe {
+        let handle = OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, 0, pid);
+        if handle != 0 {
+            CloseHandle(handle);
+            true
+        } else {
+            false
+        }
+    }
+}
+
+/// A currently-running daemon session discovered by [`walk_daemons`].
+#[derive(Debug, Clone)]
+pub struct ActiveSession {
+    pub name: String,
+    pub pid: u32,
+    /// Contents of the session's `.version` file if present and non-empty.
+    pub version: Option<String>,
+}
+
+/// Why a session's sidecar files were cleaned up during a walk.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum CleanReason {
+    /// The `.pid` file referenced a process that no longer exists.
+    ProcessGone,
+    /// The `.pid` file could not be parsed as a PID.
+    UnreadablePidFile,
+    /// A `.sock` file had no corresponding `.pid` file (unix only).
+    OrphanedSocket,
+    /// The `dashboard.pid` referenced a process that no longer exists.
+    DashboardGone,
+}
+
+/// A session whose sidecar files were removed as a side effect of a walk.
+#[derive(Debug, Clone)]
+pub struct CleanedSession {
+    pub name: String,
+    pub reason: CleanReason,
+}
+
+/// Information about the standalone dashboard process, if any.
+#[derive(Debug, Clone, Copy)]
+pub struct DashboardInfo {
+    pub pid: u32,
+    pub alive: bool,
+}
+
+/// Snapshot of daemon state under [`get_socket_dir()`] after a walk. Stale
+/// sidecar files are cleaned up as a side effect and recorded in `cleaned`.
+#[derive(Debug, Default)]
+pub struct DaemonInventory {
+    pub sessions: Vec<ActiveSession>,
+    pub cleaned: Vec<CleanedSession>,
+    pub dashboard: Option<DashboardInfo>,
+}
+
+/// Read the session's `.version` sidecar if present and non-empty.
+pub fn read_session_version(session: &str) -> Option<String> {
+    let path = get_socket_dir().join(format!("{}.version", session));
+    fs::read_to_string(&path)
+        .ok()
+        .map(|s| s.trim().to_string())
+        .filter(|s| !s.is_empty())
+}
+
+/// Walk the socket directory and classify each `.pid` / `.sock` entry.
+///
+/// - Live daemons go into `sessions` with their `.version` file contents.
+/// - Stale entries (process gone, unreadable pid, orphaned `.sock`) are
+///   cleaned via [`cleanup_stale_files`] and recorded in `cleaned`.
+/// - `dashboard.pid` lands in `dashboard` with liveness info; if the
+///   process is gone, the pid file is removed and a `DashboardGone` entry
+///   is added to `cleaned`.
+///
+/// If the socket directory doesn't exist, returns an empty inventory with
+/// no side effects.
+pub fn walk_daemons() -> DaemonInventory {
+    let socket_dir = get_socket_dir();
+    let mut inventory = DaemonInventory::default();
+
+    let entries = match fs::read_dir(&socket_dir) {
+        Ok(e) => e,
+        Err(_) => return inventory,
+    };
+
+    for entry in entries.flatten() {
+        let name = entry.file_name().to_string_lossy().to_string();
+
+        if name == "dashboard.pid" {
+            if let Ok(s) = fs::read_to_string(entry.path()) {
+                if let Ok(pid) = s.trim().parse::<u32>() {
+                    let alive = is_pid_alive(pid);
+                    inventory.dashboard = Some(DashboardInfo { pid, alive });
+                    if !alive {
+                        let _ = fs::remove_file(entry.path());
+                        inventory.cleaned.push(CleanedSession {
+                            name: "dashboard".to_string(),
+                            reason: CleanReason::DashboardGone,
+                        });
+                    }
+                }
+            }
+            continue;
+        }
+
+        let session_name = match name.strip_suffix(".pid") {
+            Some(s) if !s.is_empty() => s.to_string(),
+            _ => continue,
+        };
+
+        let pid = match fs::read_to_string(entry.path())
+            .ok()
+            .and_then(|s| s.trim().parse::<u32>().ok())
+        {
+            Some(p) => p,
+            None => {
+                cleanup_stale_files(&session_name);
+                inventory.cleaned.push(CleanedSession {
+                    name: session_name,
+                    reason: CleanReason::UnreadablePidFile,
+                });
+                continue;
+            }
+        };
+
+        if !is_pid_alive(pid) {
+            cleanup_stale_files(&session_name);
+            inventory.cleaned.push(CleanedSession {
+                name: session_name,
+                reason: CleanReason::ProcessGone,
+            });
+            continue;
+        }
+
+        let version = read_session_version(&session_name);
+        inventory.sessions.push(ActiveSession {
+            name: session_name,
+            pid,
+            version,
+        });
+    }
+
+    // Orphaned .sock files without a corresponding .pid (unix only).
+    #[cfg(unix)]
+    if let Ok(entries) = fs::read_dir(&socket_dir) {
+        for entry in entries.flatten() {
+            let name = entry.file_name().to_string_lossy().to_string();
+            if let Some(session_name) = name.strip_suffix(".sock") {
+                if session_name.is_empty() {
+                    continue;
+                }
+                let pid_path = socket_dir.join(format!("{}.pid", session_name));
+                if !pid_path.exists() {
+                    cleanup_stale_files(session_name);
+                    inventory.cleaned.push(CleanedSession {
+                        name: session_name.to_string(),
+                        reason: CleanReason::OrphanedSocket,
+                    });
+                }
+            }
+        }
+    }
+
+    inventory
+}
+
 #[cfg(windows)]
 fn get_port_path(session: &str) -> PathBuf {
     get_socket_dir().join(format!("{}.port", session))

cli/src/doctor/chrome.rs

@@ -0,0 +1,156 @@
+//! Check the Chrome install: binary path, version, cache dirs, user-data
+//! dir, and the optional lightpanda engine.
+
+use std::env;
+use std::path::{Path, PathBuf};
+
+use super::helpers::which_exists;
+use super::{Check, Status};
+
+pub(super) fn check(checks: &mut Vec<Check>) {
+    let category = "Chrome";
+
+    let chrome = crate::native::cdp::chrome::find_chrome();
+    match chrome {
+        Some(path) => {
+            let label = path.display().to_string();
+            match query_chrome_version(&path) {
+                Some(version) => checks.push(Check::new(
+                    "chrome.installed",
+                    category,
+                    Status::Pass,
+                    format!("{} at {}", version, label),
+                )),
+                None => checks.push(Check::new(
+                    "chrome.installed",
+                    category,
+                    Status::Pass,
+                    format!("Chrome at {} (version unknown)", label),
+                )),
+            }
+        }
+        None => checks.push(
+            Check::new(
+                "chrome.installed",
+                category,
+                Status::Fail,
+                "No Chrome binary found",
+            )
+            .with_fix("agent-browser install"),
+        ),
+    }
+
+    let cache_dir = crate::install::get_browsers_dir();
+    if cache_dir.exists() {
+        checks.push(Check::new(
+            "chrome.cache_dir",
+            category,
+            Status::Info,
+            format!("Cache dir {}", cache_dir.display()),
+        ));
+    }
+
+    if let Some(puppeteer_dir) = puppeteer_cache_dir() {
+        if puppeteer_dir.exists() {
+            checks.push(Check::new(
+                "chrome.puppeteer_cache",
+                category,
+                Status::Info,
+                format!(
+                    "Puppeteer cache also present: {} (will be used as a fallback)",
+                    puppeteer_dir.display()
+                ),
+            ));
+        }
+    }
+
+    if let Some(user_data_dir) = crate::native::cdp::chrome::find_chrome_user_data_dir() {
+        let profiles = crate::native::cdp::chrome::list_chrome_profiles(&user_data_dir);
+        let count = profiles.len();
+        let dir_label = user_data_dir.display().to_string();
+        if count == 0 {
+            checks.push(Check::new(
+                "chrome.user_data_dir",
+                category,
+                Status::Info,
+                format!(
+                    "Chrome user data dir found ({}), no profiles parsed",
+                    dir_label
+                ),
+            ));
+        } else {
+            checks.push(Check::new(
+                "chrome.user_data_dir",
+                category,
+                Status::Info,
+                format!("{} Chrome profile(s) at {}", count, dir_label),
+            ));
+        }
+    }
+
+    if let Ok(engine) = env::var("AGENT_BROWSER_ENGINE") {
+        if engine == "lightpanda" {
+            // Best-effort PATH lookup; absence is FAIL only when the user
+            // explicitly opted into the lightpanda engine.
+            if which_exists("lightpanda") {
+                checks.push(Check::new(
+                    "chrome.engine_lightpanda",
+                    category,
+                    Status::Pass,
+                    "Lightpanda binary on PATH",
+                ));
+            } else {
+                checks.push(
+                    Check::new(
+                        "chrome.engine_lightpanda",
+                        category,
+                        Status::Fail,
+                        "AGENT_BROWSER_ENGINE=lightpanda but no lightpanda binary on PATH",
+                    )
+                    .with_fix("install lightpanda or unset AGENT_BROWSER_ENGINE"),
+                );
+            }
+        }
+    }
+}
+
+fn query_chrome_version(path: &Path) -> Option<String> {
+    let output = std::process::Command::new(path)
+        .arg("--version")
+        .output()
+        .ok()?;
+    if !output.status.success() {
+        return None;
+    }
+    let s = String::from_utf8_lossy(&output.stdout).trim().to_string();
+    if s.is_empty() {
+        None
+    } else {
+        Some(s)
+    }
+}
+
+pub(super) fn puppeteer_cache_dir() -> Option<PathBuf> {
+    if let Ok(p) = env::var("PUPPETEER_CACHE_DIR") {
+        return Some(PathBuf::from(p));
+    }
+    dirs::home_dir().map(|h| h.join(".cache").join("puppeteer"))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_puppeteer_cache_dir_returns_sensible_default() {
+        // When PUPPETEER_CACHE_DIR is unset, we fall back to
+        // ~/.cache/puppeteer. Mutating env vars here would race with other
+        // tests, so just verify the fallback path is shaped correctly.
+        if env::var("PUPPETEER_CACHE_DIR").is_err() {
+            let dir = puppeteer_cache_dir().expect("home dir should resolve in tests");
+            let s = dir.to_string_lossy();
+            assert!(s.contains(".cache"));
+            assert!(s.ends_with("puppeteer"));
+        }
+    }
+}

cli/src/doctor/config.rs

@@ -0,0 +1,90 @@
+//! Check user config files: `~/.agent-browser/config.json`,
+//! `./agent-browser.json`, and any file referenced by
+//! `AGENT_BROWSER_CONFIG`.
+
+use std::env;
+use std::path::PathBuf;
+
+use super::helpers::parse_json_file;
+use super::{Check, Status};
+
+pub(super) fn check(checks: &mut Vec<Check>) {
+    let category = "Config";
+
+    let user_path = dirs::home_dir().map(|d| d.join(".agent-browser").join("config.json"));
+    if let Some(p) = user_path {
+        if p.exists() {
+            match parse_json_file(&p) {
+                Ok(_) => checks.push(Check::new(
+                    "config.user",
+                    category,
+                    Status::Pass,
+                    format!("{} (valid JSON)", p.display()),
+                )),
+                Err(e) => checks.push(
+                    Check::new(
+                        "config.user",
+                        category,
+                        Status::Fail,
+                        format!("{}: {}", p.display(), e),
+                    )
+                    .with_fix(format!("edit {}", p.display())),
+                ),
+            }
+        }
+    }
+
+    let project_path = PathBuf::from("agent-browser.json");
+    if project_path.exists() {
+        match parse_json_file(&project_path) {
+            Ok(_) => checks.push(Check::new(
+                "config.project",
+                category,
+                Status::Pass,
+                format!("{} (valid JSON)", project_path.display()),
+            )),
+            Err(e) => checks.push(
+                Check::new(
+                    "config.project",
+                    category,
+                    Status::Fail,
+                    format!("{}: {}", project_path.display(), e),
+                )
+                .with_fix(format!("edit {}", project_path.display())),
+            ),
+        }
+    }
+
+    if let Ok(custom) = env::var("AGENT_BROWSER_CONFIG") {
+        let p = PathBuf::from(&custom);
+        if !p.exists() {
+            checks.push(
+                Check::new(
+                    "config.custom",
+                    category,
+                    Status::Fail,
+                    format!("AGENT_BROWSER_CONFIG points to missing file: {}", custom),
+                )
+                .with_fix("update or unset AGENT_BROWSER_CONFIG"),
+            );
+        } else {
+            match parse_json_file(&p) {
+                Ok(_) => checks.push(Check::new(
+                    "config.custom",
+                    category,
+                    Status::Pass,
+                    format!("AGENT_BROWSER_CONFIG: {} (valid JSON)", custom),
+                )),
+                Err(e) => checks.push(
+                    Check::new(
+                        "config.custom",
+                        category,
+                        Status::Fail,
+                        format!("AGENT_BROWSER_CONFIG: {}: {}", custom, e),
+                    )
+                    .with_fix(format!("edit {}", custom)),
+                ),
+            }
+        }
+    }
+}

cli/src/doctor/daemon.rs

@@ -0,0 +1,70 @@
+//! Check running daemons: inventory of sessions, version match with the
+//! CLI, and stale sidecar files cleaned up as a side effect of the walk.
+
+use super::{Check, Status};
+use crate::connection::{walk_daemons, CleanReason};
+
+pub(super) fn check(checks: &mut Vec<Check>) {
+    let category = "Daemons";
+    let cli_version = env!("CARGO_PKG_VERSION");
+
+    let inventory = walk_daemons();
+
+    for cleaned in &inventory.cleaned {
+        let reason = match cleaned.reason {
+            CleanReason::ProcessGone | CleanReason::DashboardGone => "process gone",
+            CleanReason::UnreadablePidFile => "unreadable pid file",
+            CleanReason::OrphanedSocket => "orphaned socket",
+        };
+        checks.push(Check::new(
+            format!("daemon.cleaned.{}", cleaned.name),
+            category,
+            Status::Warn,
+            format!("Cleaned stale files: {} ({})", cleaned.name, reason),
+        ));
+    }
+
+    if inventory.sessions.is_empty() {
+        checks.push(Check::new(
+            "daemon.active",
+            category,
+            Status::Pass,
+            "No active daemons",
+        ));
+    } else {
+        for session in &inventory.sessions {
+            let version_match = session.version.as_deref() == Some(cli_version);
+            let status = if version_match {
+                Status::Pass
+            } else {
+                Status::Warn
+            };
+            let suffix = if version_match {
+                String::new()
+            } else {
+                format!(" (version mismatch with CLI {})", cli_version)
+            };
+            let mut check = Check::new(
+                format!("daemon.session.{}", session.name),
+                category,
+                status,
+                format!("Session {} (pid {}){}", session.name, session.pid, suffix),
+            );
+            if !version_match {
+                check = check.with_fix(format!("agent-browser --session {} close", session.name));
+            }
+            checks.push(check);
+        }
+    }
+
+    if let Some(dashboard) = inventory.dashboard {
+        if dashboard.alive {
+            checks.push(Check::new(
+                "daemon.dashboard",
+                category,
+                Status::Pass,
+                format!("Dashboard server running (pid {})", dashboard.pid),
+            ));
+        }
+    }
+}

cli/src/doctor/environment.rs

@@ -0,0 +1,140 @@
+//! Check the local environment: CLI version, platform, state/socket dirs,
+//! and free disk space.
+
+use std::path::Path;
+
+use super::helpers::{disk_free_bytes, human_size, is_writable_dir};
+use super::{Check, Status};
+use crate::connection::get_socket_dir;
+use crate::native::state::get_state_dir;
+
+pub(super) fn check(checks: &mut Vec<Check>) {
+    let category = "Environment";
+
+    let version = env!("CARGO_PKG_VERSION");
+    let platform = format!("{} {}", std::env::consts::OS, std::env::consts::ARCH);
+    checks.push(Check::new(
+        "env.version",
+        category,
+        Status::Pass,
+        format!("CLI version {} ({})", version, platform),
+    ));
+
+    match dirs::home_dir() {
+        Some(home) => checks.push(Check::new(
+            "env.home",
+            category,
+            Status::Pass,
+            format!("Home directory {}", home.display()),
+        )),
+        None => checks.push(Check::new(
+            "env.home",
+            category,
+            Status::Fail,
+            "Could not determine home directory",
+        )),
+    }
+
+    let state_dir = get_state_dir();
+    let socket_dir = get_socket_dir();
+
+    // Under the default setup, state and socket dirs are the same
+    // (~/.agent-browser). Collapse to a single line when they match;
+    // split when XDG_RUNTIME_DIR or AGENT_BROWSER_SOCKET_DIR diverts
+    // sockets elsewhere.
+    if state_dir == socket_dir {
+        push_dir_check(
+            checks,
+            "env.state_dir",
+            category,
+            "State and socket directory",
+            &state_dir,
+        );
+    } else {
+        push_dir_check(
+            checks,
+            "env.state_dir",
+            category,
+            "State directory",
+            &state_dir,
+        );
+        push_dir_check(
+            checks,
+            "env.socket_dir",
+            category,
+            "Socket directory",
+            &socket_dir,
+        );
+    }
+
+    match disk_free_bytes(&state_dir) {
+        Some(bytes) => {
+            let mb = bytes / (1024 * 1024);
+            let human = human_size(bytes);
+            if mb < 500 {
+                checks.push(
+                    Check::new(
+                        "env.disk_free",
+                        category,
+                        Status::Warn,
+                        format!("Low disk space at state dir: {} free", human),
+                    )
+                    .with_fix("free up disk space; Chrome installs require ~500 MB"),
+                );
+            } else {
+                checks.push(Check::new(
+                    "env.disk_free",
+                    category,
+                    Status::Pass,
+                    format!("{} free at state dir", human),
+                ));
+            }
+        }
+        None => checks.push(Check::new(
+            "env.disk_free",
+            category,
+            Status::Info,
+            "Disk free check unavailable on this platform",
+        )),
+    }
+}
+
+fn push_dir_check(
+    checks: &mut Vec<Check>,
+    id: &'static str,
+    category: &'static str,
+    label: &str,
+    dir: &Path,
+) {
+    if dir.exists() {
+        if is_writable_dir(dir) {
+            checks.push(Check::new(
+                id,
+                category,
+                Status::Pass,
+                format!("{} {}", label, dir.display()),
+            ));
+        } else {
+            checks.push(
+                Check::new(
+                    id,
+                    category,
+                    Status::Fail,
+                    format!("{} not writable: {}", label, dir.display()),
+                )
+                .with_fix(format!("chmod u+rwx {}", dir.display())),
+            );
+        }
+    } else {
+        checks.push(Check::new(
+            id,
+            category,
+            Status::Info,
+            format!(
+                "{} does not exist yet (will be created on first use): {}",
+                label,
+                dir.display()
+            ),
+        ));
+    }
+}

cli/src/doctor/fix.rs

@@ -0,0 +1,247 @@
+//! Destructive repair actions behind `--fix`: reinstall Chrome, close
+//! version-mismatched daemons, purge expired state files, and generate a
+//! missing encryption key.
+
+use std::env;
+use std::fs;
+use std::path::Path;
+use std::time::{Duration, SystemTime};
+
+#[cfg(unix)]
+use std::os::unix::fs::PermissionsExt;
+
+use serde_json::json;
+
+use super::helpers::new_id;
+use super::{Check, Status};
+use crate::connection::{cleanup_stale_files, send_command, walk_daemons};
+use crate::native::state::{get_sessions_dir, get_state_dir};
+
+pub(super) fn run(checks: &mut [Check], fixed: &mut Vec<String>) {
+    // `close_all_sessions` is expensive and closes every session at once, so
+    // only fire it on the first daemon.session.* Warn we encounter. Subsequent
+    // daemon.session.* Warn checks piggy-back on the same result.
+    let mut daemons_closed: Option<usize> = None;
+
+    for c in checks.iter_mut() {
+        match c.id.as_str() {
+            "chrome.installed" if c.status == Status::Fail => {
+                let installed = attempt_chrome_install();
+                if installed {
+                    fixed.push("Reinstalled Chrome".to_string());
+                    c.status = Status::Pass;
+                    c.message = format!("{} (fixed by --fix)", c.message);
+                    c.fix = None;
+                }
+            }
+            id if id.starts_with("daemon.session.") && c.status == Status::Warn => {
+                let killed = *daemons_closed.get_or_insert_with(|| {
+                    let n = close_all_sessions();
+                    if n > 0 {
+                        fixed.push(format!("Closed {} version-mismatched daemon(s)", n));
+                    }
+                    n
+                });
+                if killed > 0 {
+                    c.status = Status::Pass;
+                    c.message = format!("{} (fixed by --fix)", c.message);
+                    c.fix = None;
+                }
+            }
+            "security.state_count" if c.status == Status::Warn => {
+                let removed = purge_old_state();
+                if removed > 0 {
+                    fixed.push(format!("Deleted {} expired state file(s)", removed));
+                    c.status = Status::Pass;
+                    c.message = format!("{} (fixed by --fix)", c.message);
+                    c.fix = None;
+                }
+            }
+            "security.encryption_key" if c.status == Status::Info => {
+                let generated = create_encryption_key();
+                if generated {
+                    fixed.push("Generated encryption key".to_string());
+                    c.status = Status::Pass;
+                    c.message = format!("{} (fixed by --fix)", c.message);
+                    c.fix = None;
+                }
+            }
+            _ => {}
+        }
+    }
+}
+
+fn attempt_chrome_install() -> bool {
+    // run_install() uses process::exit on failure, so we shell out to ourselves
+    // to avoid taking down the doctor process if the install fails.
+    let exe = match std::env::current_exe() {
+        Ok(p) => p,
+        Err(_) => return false,
+    };
+    std::process::Command::new(exe)
+        .arg("install")
+        .status()
+        .map(|s| s.success())
+        .unwrap_or(false)
+}
+
+fn close_all_sessions() -> usize {
+    let mut killed = 0;
+    for session in &walk_daemons().sessions {
+        let cmd = json!({ "id": new_id(), "action": "close" });
+        if send_command(cmd, &session.name).is_ok() {
+            killed += 1;
+        }
+        cleanup_stale_files(&session.name);
+    }
+    killed
+}
+
+fn purge_old_state() -> usize {
+    let dir = get_sessions_dir();
+    let expire_days = env::var("AGENT_BROWSER_STATE_EXPIRE_DAYS")
+        .ok()
+        .and_then(|s| s.parse::<u64>().ok())
+        .unwrap_or(30);
+    let cutoff = SystemTime::now()
+        .checked_sub(Duration::from_secs(expire_days * 86_400))
+        .unwrap_or(SystemTime::UNIX_EPOCH);
+    let mut removed = 0;
+    if let Ok(entries) = fs::read_dir(&dir) {
+        for entry in entries.flatten() {
+            if entry.file_type().map(|t| t.is_file()).unwrap_or(false) {
+                if let Ok(meta) = entry.metadata() {
+                    if let Ok(modified) = meta.modified() {
+                        if modified < cutoff && fs::remove_file(entry.path()).is_ok() {
+                            removed += 1;
+                        }
+                    }
+                }
+            }
+        }
+    }
+    removed
+}
+
+fn create_encryption_key() -> bool {
+    create_encryption_key_at(&get_state_dir())
+}
+
+fn create_encryption_key_at(dir: &Path) -> bool {
+    if fs::create_dir_all(dir).is_err() {
+        return false;
+    }
+    #[cfg(unix)]
+    {
+        let _ = fs::set_permissions(dir, fs::Permissions::from_mode(0o700));
+    }
+    let path = dir.join(".encryption-key");
+    if path.exists() {
+        return false;
+    }
+    let mut buf = [0u8; 32];
+    if getrandom::getrandom(&mut buf).is_err() {
+        return false;
+    }
+    let hex: String = buf.iter().map(|b| format!("{:02x}", b)).collect();
+    if fs::write(&path, format!("{}\n", hex)).is_err() {
+        return false;
+    }
+    #[cfg(unix)]
+    {
+        let _ = fs::set_permissions(&path, fs::Permissions::from_mode(0o600));
+    }
+    true
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tempfile::TempDir;
+
+    #[test]
+    fn test_create_encryption_key_at_writes_64_char_hex_key() {
+        let tmp = TempDir::new().unwrap();
+        let dir = tmp.path().join("state");
+
+        assert!(create_encryption_key_at(&dir));
+
+        let key = dir.join(".encryption-key");
+        assert!(key.exists(), "key file should be created");
+
+        let contents = fs::read_to_string(&key).unwrap();
+        let trimmed = contents.trim();
+        assert_eq!(trimmed.len(), 64, "key should be 64 hex chars");
+        assert!(
+            trimmed.chars().all(|c| c.is_ascii_hexdigit()),
+            "key should be all hex digits"
+        );
+    }
+
+    #[test]
+    fn test_create_encryption_key_at_is_idempotent() {
+        let tmp = TempDir::new().unwrap();
+        let dir = tmp.path().join("state");
+        assert!(create_encryption_key_at(&dir));
+
+        let original = fs::read_to_string(dir.join(".encryption-key")).unwrap();
+
+        // Second call returns false and must not overwrite the existing key.
+        assert!(!create_encryption_key_at(&dir));
+        let after = fs::read_to_string(dir.join(".encryption-key")).unwrap();
+        assert_eq!(original, after);
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn test_create_encryption_key_at_sets_0600_perms() {
+        let tmp = TempDir::new().unwrap();
+        let dir = tmp.path().join("state");
+
+        assert!(create_encryption_key_at(&dir));
+
+        let key = dir.join(".encryption-key");
+        let mode = fs::metadata(&key).unwrap().permissions().mode() & 0o777;
+        assert_eq!(mode, 0o600, "key file should be 0600, got {:o}", mode);
+    }
+
+    #[cfg(unix)]
+    #[test]
+    fn test_run_fixes_generates_missing_encryption_key() {
+        // Reaches the Info-status arm in run_fixes that was previously
+        // unreachable due to an early-continue guard. Overrides HOME so
+        // get_state_dir() resolves under a temp dir.
+        let guard = crate::test_utils::EnvGuard::new(&["HOME"]);
+        let tmp = TempDir::new().unwrap();
+        guard.set("HOME", tmp.path().to_str().unwrap());
+
+        let mut checks = vec![Check::new(
+            "security.encryption_key",
+            "Security",
+            Status::Info,
+            "No encryption key set",
+        )
+        .with_fix("export AGENT_BROWSER_ENCRYPTION_KEY=...")];
+        let mut fixed = Vec::new();
+
+        run(&mut checks, &mut fixed);
+
+        assert_eq!(
+            checks[0].status,
+            Status::Pass,
+            "Info check should transition to Pass after --fix"
+        );
+        assert!(
+            checks[0].fix.is_none(),
+            "fix hint should be cleared after repair"
+        );
+        assert!(
+            fixed.iter().any(|s| s.contains("encryption key")),
+            "fixed summary should mention the key generation"
+        );
+        assert!(
+            tmp.path().join(".agent-browser/.encryption-key").exists(),
+            "key file should exist at ~/.agent-browser/.encryption-key"
+        );
+    }
+}

cli/src/doctor/helpers.rs

@@ -0,0 +1,180 @@
+//! Stateless helpers shared across doctor submodules.
+
+use std::fs;
+use std::path::Path;
+use std::time::SystemTime;
+
+use serde_json::Value;
+
+pub(super) fn is_writable_dir(path: &Path) -> bool {
+    fs::metadata(path)
+        .map(|m| !m.permissions().readonly())
+        .unwrap_or(false)
+}
+
+pub(super) fn human_size(bytes: u64) -> String {
+    const UNITS: &[&str] = &["B", "KB", "MB", "GB", "TB"];
+    let mut value = bytes as f64;
+    let mut unit = 0;
+    while value >= 1024.0 && unit < UNITS.len() - 1 {
+        value /= 1024.0;
+        unit += 1;
+    }
+    if unit == 0 {
+        format!("{} {}", bytes, UNITS[0])
+    } else {
+        format!("{:.1} {}", value, UNITS[unit])
+    }
+}
+
+#[cfg(unix)]
+pub(super) fn disk_free_bytes(path: &Path) -> Option<u64> {
+    use std::ffi::CString;
+    use std::os::unix::ffi::OsStrExt;
+    use std::path::PathBuf;
+
+    // Walk up to the first existing ancestor (for fresh installs where the
+    // state dir hasn't been created yet).
+    let mut probe: PathBuf = path.to_path_buf();
+    while !probe.exists() {
+        match probe.parent() {
+            Some(p) => probe = p.to_path_buf(),
+            None => return None,
+        }
+    }
+    let c_path = CString::new(probe.as_os_str().as_bytes()).ok()?;
+    let mut stat: libc::statvfs = unsafe { std::mem::zeroed() };
+    if unsafe { libc::statvfs(c_path.as_ptr(), &mut stat) } != 0 {
+        return None;
+    }
+    Some(stat.f_bavail as u64 * stat.f_frsize)
+}
+
+#[cfg(windows)]
+pub(super) fn disk_free_bytes(_path: &Path) -> Option<u64> {
+    None
+}
+
+#[cfg(not(any(unix, windows)))]
+pub(super) fn disk_free_bytes(_path: &Path) -> Option<u64> {
+    None
+}
+
+pub(super) fn which_exists(name: &str) -> bool {
+    let probe = if cfg!(target_os = "windows") {
+        "where"
+    } else {
+        "which"
+    };
+    std::process::Command::new(probe)
+        .arg(name)
+        .stdout(std::process::Stdio::null())
+        .stderr(std::process::Stdio::null())
+        .status()
+        .map(|s| s.success())
+        .unwrap_or(false)
+}
+
+pub(super) fn parse_json_file(path: &Path) -> Result<(), String> {
+    let content = fs::read_to_string(path).map_err(|e| format!("read failed: {}", e))?;
+    serde_json::from_str::<Value>(&content).map_err(|e| format!("invalid JSON: {}", e))?;
+    Ok(())
+}
+
+/// Generate a unique `doctor-<pid>-<micros>` id for JSON command envelopes.
+pub(super) fn new_id() -> String {
+    format!(
+        "doctor-{}-{}",
+        std::process::id(),
+        SystemTime::now()
+            .duration_since(SystemTime::UNIX_EPOCH)
+            .map(|d| d.as_micros())
+            .unwrap_or(0)
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use tempfile::TempDir;
+
+    #[test]
+    fn test_human_size_units() {
+        assert_eq!(human_size(0), "0 B");
+        assert_eq!(human_size(512), "512 B");
+        assert_eq!(human_size(1024), "1.0 KB");
+        assert_eq!(human_size(1024 * 1024), "1.0 MB");
+        assert_eq!(human_size(1024 * 1024 * 1024), "1.0 GB");
+        assert_eq!(human_size(1_500_000), "1.4 MB");
+    }
+
+    #[test]
+    fn test_disk_free_walks_up_to_existing_ancestor() {
+        let dir = TempDir::new().unwrap();
+        let nested = dir.path().join("a/b/c/d");
+        let bytes = disk_free_bytes(&nested);
+        if cfg!(unix) {
+            assert!(bytes.is_some());
+            assert!(bytes.unwrap() > 0);
+        }
+    }
+
+    #[test]
+    fn test_is_writable_dir_matches_metadata() {
+        let dir = TempDir::new().unwrap();
+        assert!(is_writable_dir(dir.path()));
+
+        let missing = dir.path().join("does-not-exist");
+        assert!(!is_writable_dir(&missing));
+    }
+
+    #[test]
+    fn test_which_exists_matches_common_binaries() {
+        // `sh` exists on every unix; `cmd` exists on windows.
+        let probe = if cfg!(target_os = "windows") {
+            "cmd"
+        } else {
+            "sh"
+        };
+        assert!(which_exists(probe));
+        assert!(!which_exists(
+            "agent-browser-this-does-not-exist-please-dont-install-it"
+        ));
+    }
+
+    #[test]
+    fn test_parse_json_file_valid_and_invalid() {
+        let dir = TempDir::new().unwrap();
+        let valid = dir.path().join("ok.json");
+        fs::write(&valid, r#"{"k": 1}"#).unwrap();
+        assert!(parse_json_file(&valid).is_ok());
+
+        let invalid = dir.path().join("bad.json");
+        fs::write(&invalid, "{not json}").unwrap();
+        let err = parse_json_file(&invalid).unwrap_err();
+        assert!(err.contains("invalid JSON"));
+
+        let missing = dir.path().join("nope.json");
+        let err = parse_json_file(&missing).unwrap_err();
+        assert!(err.contains("read failed"));
+    }
+
+    #[test]
+    fn test_parse_json_file_accepts_arrays() {
+        // The config parser rejects arrays at the Config type level, but
+        // doctor only checks syntactic JSON validity so it should accept
+        // both arrays and objects.
+        let dir = TempDir::new().unwrap();
+        let path = dir.path().join("arr.json");
+        fs::write(&path, r#"[1, 2, 3]"#).unwrap();
+        assert!(parse_json_file(&path).is_ok());
+    }
+
+    #[test]
+    fn test_new_id_is_unique_per_call() {
+        let a = new_id();
+        let b = new_id();
+        assert_ne!(a, b);
+        assert!(a.starts_with("doctor-"));
+    }
+}

cli/src/doctor/launch.rs

@@ -0,0 +1,184 @@
+//! Live launch test: spawn a scratch daemon session, launch headless
+//! Chrome, navigate to `about:blank`, then close. Skipped under `--quick`.
+//!
+//! A `LaunchGuard` Drop impl ensures the scratch session is closed and its
+//! sidecar files cleaned even on panic or early return.
+
+use std::env;
+use std::time::{Duration, Instant, SystemTime};
+
+use serde_json::{json, Value};
+
+use super::helpers::new_id;
+use super::{Check, Status};
+use crate::connection::{cleanup_stale_files, ensure_daemon, send_command, DaemonOptions};
+
+pub(super) fn check(checks: &mut Vec<Check>) {
+    let category = "Launch test";
+
+    if env::var("AGENT_BROWSER_PROVIDER").is_ok() {
+        checks.push(Check::new(
+            "launch.skipped.provider",
+            category,
+            Status::Info,
+            "Skipped (AGENT_BROWSER_PROVIDER is set; would consume cloud quota)",
+        ));
+        return;
+    }
+    if env::var("AGENT_BROWSER_CDP").is_ok() {
+        checks.push(Check::new(
+            "launch.skipped.cdp",
+            category,
+            Status::Info,
+            "Skipped (AGENT_BROWSER_CDP is set; would attach to a real browser)",
+        ));
+        return;
+    }
+
+    let session = format!(
+        "doctor-{}-{}",
+        std::process::id(),
+        SystemTime::now()
+            .duration_since(SystemTime::UNIX_EPOCH)
+            .map(|d| d.as_millis())
+            .unwrap_or(0)
+    );
+
+    // Armed after `ensure_daemon` succeeds so we don't send a stray `close`
+    // or delete sidecar files for a daemon that never started. On every early
+    // return past the `Some(...)` assignment below, Drop runs one close and
+    // one `cleanup_stale_files`.
+    let mut _guard: Option<LaunchGuard> = None;
+
+    let opts = DaemonOptions {
+        headed: false,
+        debug: false,
+        executable_path: None,
+        extensions: &[],
+        args: None,
+        user_agent: None,
+        proxy: None,
+        proxy_bypass: None,
+        proxy_username: None,
+        proxy_password: None,
+        ignore_https_errors: false,
+        allow_file_access: false,
+        profile: None,
+        state: None,
+        provider: None,
+        device: None,
+        session_name: None,
+        download_path: None,
+        allowed_domains: None,
+        action_policy: None,
+        confirm_actions: None,
+        engine: None,
+        auto_connect: false,
+        idle_timeout: None,
+        default_timeout: None,
+        cdp: None,
+        no_auto_dialog: false,
+    };
+
+    let started = Instant::now();
+    if let Err(e) = ensure_daemon(&session, &opts) {
+        checks.push(
+            Check::new(
+                "launch.daemon",
+                category,
+                Status::Fail,
+                format!("Could not start daemon: {}", e),
+            )
+            .with_fix("check Chrome install and re-run with --debug"),
+        );
+        return;
+    }
+    _guard = Some(LaunchGuard {
+        session: session.clone(),
+    });
+
+    let launch_cmd = json!({
+        "id": new_id(),
+        "action": "launch",
+        "headless": true,
+    });
+    if let Err(e) = send_json(launch_cmd, &session) {
+        checks.push(
+            Check::new(
+                "launch.launch",
+                category,
+                Status::Fail,
+                format!("Browser launch failed: {}", e),
+            )
+            .with_fix("agent-browser install   # or check --debug output"),
+        );
+        return;
+    }
+
+    let open_cmd = json!({
+        "id": new_id(),
+        "action": "navigate",
+        "url": "about:blank",
+    });
+    if let Err(e) = send_json(open_cmd, &session) {
+        checks.push(
+            Check::new(
+                "launch.navigate",
+                category,
+                Status::Fail,
+                format!("Navigation to about:blank failed: {}", e),
+            )
+            .with_fix("re-run with --debug for full launch logs"),
+        );
+        return;
+    }
+
+    // Close + stale-file cleanup happen exactly once via LaunchGuard::drop at
+    // end of scope; no explicit close here.
+    let elapsed = started.elapsed();
+    let secs = elapsed.as_secs_f64();
+    if elapsed > Duration::from_secs(5) {
+        checks.push(Check::new(
+            "launch.elapsed",
+            category,
+            Status::Warn,
+            format!(
+                "Headless launch + about:blank in {:.2}s (slow; expected < 5s)",
+                secs
+            ),
+        ));
+    } else {
+        checks.push(Check::new(
+            "launch.elapsed",
+            category,
+            Status::Pass,
+            format!("Headless launch + about:blank in {:.2}s", secs),
+        ));
+    }
+}
+
+fn send_json(cmd: Value, session: &str) -> Result<(), String> {
+    match send_command(cmd, session) {
+        Ok(resp) => {
+            if resp.success {
+                Ok(())
+            } else {
+                Err(resp.error.unwrap_or_else(|| "unknown error".to_string()))
+            }
+        }
+        Err(e) => Err(e),
+    }
+}
+
+/// Best-effort cleanup when the launch test panics or returns early.
+struct LaunchGuard {
+    session: String,
+}
+
+impl Drop for LaunchGuard {
+    fn drop(&mut self) {
+        let close_cmd = json!({ "id": new_id(), "action": "close" });
+        let _ = send_command(close_cmd, &self.session);
+        cleanup_stale_files(&self.session);
+    }
+}

cli/src/doctor/mod.rs

@@ -0,0 +1,289 @@
+//! Diagnose an agent-browser installation.
+//!
+//! Runs a battery of checks across environment, Chrome install, daemon
+//! state, config files, encryption, providers, network reachability, and
+//! a live headless browser launch test.
+//!
+//! Auto-cleans stale daemon socket/pid/version sidecar files. Destructive
+//! repairs (reinstalling Chrome, purging old state files, generating a
+//! missing encryption key) are gated behind `--fix`.
+
+mod chrome;
+mod config;
+mod daemon;
+mod environment;
+mod fix;
+mod helpers;
+mod launch;
+mod network;
+mod providers;
+mod security;
+
+use serde_json::{json, Value};
+
+use crate::color;
+
+#[derive(Default, Clone, Copy)]
+pub struct DoctorOptions {
+    pub offline: bool,
+    pub quick: bool,
+    pub fix: bool,
+    pub json: bool,
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+#[repr(u8)]
+pub(crate) enum Status {
+    Pass,
+    Warn,
+    Fail,
+    Info,
+}
+
+impl Status {
+    fn as_str(&self) -> &'static str {
+        match self {
+            Status::Pass => "pass",
+            Status::Warn => "warn",
+            Status::Fail => "fail",
+            Status::Info => "info",
+        }
+    }
+
+    fn label(&self) -> String {
+        match self {
+            Status::Pass => color::green("pass"),
+            Status::Warn => color::yellow("warn"),
+            Status::Fail => color::red("fail"),
+            Status::Info => color::dim("info"),
+        }
+    }
+}
+
+#[derive(Clone)]
+pub(crate) struct Check {
+    pub id: String,
+    pub category: &'static str,
+    pub status: Status,
+    pub message: String,
+    pub fix: Option<String>,
+}
+
+impl Check {
+    fn new(
+        id: impl Into<String>,
+        category: &'static str,
+        status: Status,
+        message: impl Into<String>,
+    ) -> Self {
+        Self {
+            id: id.into(),
+            category,
+            status,
+            message: message.into(),
+            fix: None,
+        }
+    }
+
+    fn with_fix(mut self, fix: impl Into<String>) -> Self {
+        self.fix = Some(fix.into());
+        self
+    }
+}
+
+/// Run the doctor command. Returns the process exit code.
+pub fn run_doctor(opts: DoctorOptions) -> i32 {
+    let mut checks: Vec<Check> = Vec::new();
+    let mut fixed: Vec<String> = Vec::new();
+
+    environment::check(&mut checks);
+    chrome::check(&mut checks);
+    daemon::check(&mut checks);
+    config::check(&mut checks);
+    security::check(&mut checks);
+    providers::check(&mut checks);
+
+    if !opts.offline {
+        network::check(&mut checks);
+    }
+
+    if !opts.quick {
+        launch::check(&mut checks);
+    }
+
+    if opts.fix {
+        fix::run(&mut checks, &mut fixed);
+    }
+
+    let summary = summarize(&checks);
+    let exit_code = if summary.fail > 0 { 1 } else { 0 };
+
+    if opts.json {
+        print_json(&checks, &summary, &fixed, exit_code == 0);
+    } else {
+        print_text(&checks, &summary, &fixed, opts.fix);
+    }
+
+    exit_code
+}
+
+struct Summary {
+    pass: usize,
+    warn: usize,
+    fail: usize,
+}
+
+fn summarize(checks: &[Check]) -> Summary {
+    let mut s = Summary {
+        pass: 0,
+        warn: 0,
+        fail: 0,
+    };
+    for c in checks {
+        match c.status {
+            Status::Pass => s.pass += 1,
+            Status::Warn => s.warn += 1,
+            Status::Fail => s.fail += 1,
+            Status::Info => {}
+        }
+    }
+    s
+}
+
+fn print_text(checks: &[Check], summary: &Summary, fixed: &[String], fix_ran: bool) {
+    println!("{}", color::bold("agent-browser doctor"));
+
+    let mut current_category = "";
+    for c in checks {
+        if c.category != current_category {
+            current_category = c.category;
+            println!();
+            println!("{}", color::bold(current_category));
+        }
+        println!("  {}  {}", c.status.label(), c.message);
+        if let Some(fix) = &c.fix {
+            println!("        {} {}", color::dim("fix:"), fix);
+        }
+    }
+
+    if !fixed.is_empty() {
+        println!();
+        println!("{}", color::bold("Fixed"));
+        for line in fixed {
+            println!("  {}  {}", color::green("done"), line);
+        }
+    }
+
+    println!();
+    let line = format!(
+        "Summary: {} pass, {} warn, {} fail",
+        summary.pass, summary.warn, summary.fail
+    );
+    if summary.fail > 0 {
+        println!("{}", color::red(&line));
+    } else if summary.warn > 0 {
+        println!("{}", color::yellow(&line));
+    } else {
+        println!("{}", color::green(&line));
+    }
+
+    if !fix_ran && checks.iter().any(|c| c.fix.is_some()) {
+        println!();
+        println!(
+            "{} Run with {} to attempt repairs.",
+            color::dim("tip:"),
+            color::bold("--fix")
+        );
+    }
+}
+
+fn print_json(checks: &[Check], summary: &Summary, fixed: &[String], success: bool) {
+    let checks_json: Vec<Value> = checks
+        .iter()
+        .map(|c| {
+            let mut obj = json!({
+                "id": c.id,
+                "category": c.category,
+                "status": c.status.as_str(),
+                "message": c.message,
+            });
+            if let Some(fix) = &c.fix {
+                obj["fix"] = json!(fix);
+            }
+            obj
+        })
+        .collect();
+
+    let payload = json!({
+        "success": success,
+        "summary": {
+            "pass": summary.pass,
+            "warn": summary.warn,
+            "fail": summary.fail,
+        },
+        "checks": checks_json,
+        "fixed": fixed,
+    });
+    println!("{}", payload);
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_summary_counts_each_status() {
+        let checks = vec![
+            Check::new("a", "Cat", Status::Pass, "ok"),
+            Check::new("b", "Cat", Status::Pass, "ok"),
+            Check::new("c", "Cat", Status::Warn, "meh"),
+            Check::new("d", "Cat", Status::Fail, "no"),
+            Check::new("e", "Cat", Status::Info, "fyi"),
+        ];
+        let s = summarize(&checks);
+        assert_eq!(s.pass, 2);
+        assert_eq!(s.warn, 1);
+        assert_eq!(s.fail, 1);
+    }
+
+    #[test]
+    fn test_summary_zeroes_when_only_info() {
+        let checks = vec![Check::new("a", "Cat", Status::Info, "ignored")];
+        let s = summarize(&checks);
+        assert_eq!(s.pass, 0);
+        assert_eq!(s.warn, 0);
+        assert_eq!(s.fail, 0);
+    }
+
+    #[test]
+    fn test_status_label_does_not_panic() {
+        for s in &[Status::Pass, Status::Warn, Status::Fail, Status::Info] {
+            assert!(!s.label().is_empty());
+            assert!(!s.as_str().is_empty());
+        }
+    }
+
+    #[test]
+    fn test_status_as_str_values() {
+        assert_eq!(Status::Pass.as_str(), "pass");
+        assert_eq!(Status::Warn.as_str(), "warn");
+        assert_eq!(Status::Fail.as_str(), "fail");
+        assert_eq!(Status::Info.as_str(), "info");
+    }
+
+    #[test]
+    fn test_check_new_and_with_fix() {
+        let c = Check::new("id", "cat", Status::Warn, "msg").with_fix("do thing");
+        assert_eq!(c.id, "id");
+        assert_eq!(c.category, "cat");
+        assert_eq!(c.status, Status::Warn);
+        assert_eq!(c.message, "msg");
+        assert_eq!(c.fix.as_deref(), Some("do thing"));
+    }
+
+    #[test]
+    fn test_check_new_no_fix_by_default() {
+        let c = Check::new("id", "cat", Status::Pass, "msg");
+        assert!(c.fix.is_none());
+    }
+}

cli/src/doctor/network.rs

@@ -0,0 +1,154 @@
+//! Probe reachability of the Chrome for Testing CDN, AI Gateway (if
+//! configured), and the currently-selected provider endpoint. Each probe
+//! has a 3-second timeout.
+
+use std::env;
+use std::time::{Duration, Instant};
+
+use super::{Check, Status};
+
+pub(super) fn check(checks: &mut Vec<Check>) {
+    let category = "Network";
+
+    let rt = match tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()
+    {
+        Ok(r) => r,
+        Err(e) => {
+            checks.push(Check::new(
+                "net.runtime",
+                category,
+                Status::Fail,
+                format!("Could not start tokio runtime for probes: {}", e),
+            ));
+            return;
+        }
+    };
+
+    let client = match reqwest::Client::builder()
+        .user_agent(format!("agent-browser/{}", env!("CARGO_PKG_VERSION")))
+        .timeout(Duration::from_secs(3))
+        .connect_timeout(Duration::from_secs(3))
+        .build()
+    {
+        Ok(c) => c,
+        Err(e) => {
+            checks.push(Check::new(
+                "net.client",
+                category,
+                Status::Fail,
+                format!("Could not build HTTP client: {}", e),
+            ));
+            return;
+        }
+    };
+
+    let chrome_url =
+        "https://googlechromelabs.github.io/chrome-for-testing/last-known-good-versions-with-downloads.json";
+    probe_url(
+        &rt,
+        &client,
+        checks,
+        category,
+        "net.chrome_cdn",
+        chrome_url,
+        "Chrome for Testing CDN",
+    );
+
+    if env::var("AI_GATEWAY_API_KEY").is_ok() {
+        let url = env::var("AI_GATEWAY_URL")
+            .unwrap_or_else(|_| "https://ai-gateway.vercel.sh".to_string());
+        probe_url(
+            &rt,
+            &client,
+            checks,
+            category,
+            "net.ai_gateway",
+            &url,
+            "AI Gateway",
+        );
+    }
+
+    if let Ok(provider) = env::var("AGENT_BROWSER_PROVIDER") {
+        let url: Option<String> = match provider.to_lowercase().as_str() {
+            "browserbase" => Some("https://api.browserbase.com".to_string()),
+            "browserless" => Some(
+                env::var("BROWSERLESS_API_URL")
+                    .unwrap_or_else(|_| "https://production-sfo.browserless.io".to_string()),
+            ),
+            "browseruse" | "browser-use" => Some("https://api.browser-use.com".to_string()),
+            "kernel" => Some(
+                env::var("KERNEL_ENDPOINT")
+                    .unwrap_or_else(|_| "https://api.onkernel.com".to_string()),
+            ),
+            _ => None,
+        };
+        if let Some(url) = url {
+            probe_url(
+                &rt,
+                &client,
+                checks,
+                category,
+                "net.provider",
+                &url,
+                &format!("Provider {}", provider),
+            );
+        }
+    }
+}
+
+fn probe_url(
+    rt: &tokio::runtime::Runtime,
+    client: &reqwest::Client,
+    checks: &mut Vec<Check>,
+    category: &'static str,
+    id: &'static str,
+    url: &str,
+    label: &str,
+) {
+    let started = Instant::now();
+    let result = rt.block_on(async { client.head(url).send().await });
+    let elapsed_ms = started.elapsed().as_millis();
+    match result {
+        Ok(resp) => {
+            let status = resp.status();
+            if status.is_success() || status.is_redirection() || status.as_u16() == 405 {
+                checks.push(Check::new(
+                    id,
+                    category,
+                    Status::Pass,
+                    format!(
+                        "{} reachable ({}ms, HTTP {})",
+                        label,
+                        elapsed_ms,
+                        status.as_u16()
+                    ),
+                ));
+            } else {
+                checks.push(Check::new(
+                    id,
+                    category,
+                    Status::Warn,
+                    format!(
+                        "{} returned HTTP {} after {}ms",
+                        label,
+                        status.as_u16(),
+                        elapsed_ms
+                    ),
+                ));
+            }
+        }
+        Err(e) => {
+            checks.push(
+                Check::new(
+                    id,
+                    category,
+                    Status::Fail,
+                    format!("{} unreachable after {}ms: {}", label, elapsed_ms, e),
+                )
+                .with_fix("check network connectivity / firewall / proxy settings"),
+            );
+        }
+    }
+}

cli/src/doctor/providers.rs

@@ -0,0 +1,128 @@
+//! Check remote browser providers: API key presence for Browserless,
+//! Browserbase, Browser Use, Kernel, AgentCore (AWS), Appium for iOS, and
+//! the AI Gateway chat key. Info-level unless the provider is selected
+//! via `AGENT_BROWSER_PROVIDER`.
+
+use std::env;
+
+use super::helpers::which_exists;
+use super::{Check, Status};
+
+pub(super) fn check(checks: &mut Vec<Check>) {
+    let category = "Providers";
+
+    let active = env::var("AGENT_BROWSER_PROVIDER").ok();
+    let normalized = active
+        .as_ref()
+        .map(|s| s.to_lowercase())
+        .unwrap_or_default();
+
+    let active_status = |provider: &str, ok: bool| -> Status {
+        if normalized == provider {
+            if ok {
+                Status::Pass
+            } else {
+                Status::Fail
+            }
+        } else {
+            Status::Info
+        }
+    };
+
+    let providers: &[(&str, &[&str], &str)] = &[
+        ("browserless", &["BROWSERLESS_API_KEY"], "Browserless"),
+        ("browserbase", &["BROWSERBASE_API_KEY"], "Browserbase"),
+        ("browseruse", &["BROWSER_USE_API_KEY"], "Browser Use"),
+        ("kernel", &["KERNEL_API_KEY"], "Kernel"),
+    ];
+
+    for (id, env_keys, label) in providers {
+        let present = env_keys.iter().any(|k| env::var(k).is_ok());
+        let provider_id = *id;
+        let status = active_status(provider_id, present);
+        let msg = if present {
+            format!("{}: API key present", label)
+        } else {
+            format!("{}: {} not set", label, env_keys.join(" / "))
+        };
+        let mut check = Check::new(format!("providers.{}", provider_id), category, status, msg);
+        if status == Status::Fail {
+            check = check.with_fix(format!(
+                "set {} (or unset AGENT_BROWSER_PROVIDER={})",
+                env_keys.first().copied().unwrap_or(""),
+                provider_id
+            ));
+        }
+        checks.push(check);
+    }
+
+    let aws_present = env::var("AWS_ACCESS_KEY_ID").is_ok()
+        || env::var("AWS_PROFILE").is_ok()
+        || env::var("AWS_SESSION_TOKEN").is_ok();
+    let agentcore_status = active_status("agentcore", aws_present);
+    let mut agentcore_check = Check::new(
+        "providers.agentcore",
+        category,
+        agentcore_status,
+        if aws_present {
+            "AgentCore: AWS credentials resolvable".to_string()
+        } else {
+            "AgentCore: no AWS credentials in env (AWS_ACCESS_KEY_ID / AWS_PROFILE)".to_string()
+        },
+    );
+    if agentcore_status == Status::Fail {
+        agentcore_check = agentcore_check
+            .with_fix("export AWS_ACCESS_KEY_ID / AWS_SECRET_ACCESS_KEY or AWS_PROFILE");
+    }
+    checks.push(agentcore_check);
+
+    if normalized == "ios" {
+        if which_exists("appium") {
+            checks.push(Check::new(
+                "providers.ios",
+                category,
+                Status::Pass,
+                "iOS: appium binary on PATH",
+            ));
+        } else {
+            checks.push(
+                Check::new(
+                    "providers.ios",
+                    category,
+                    Status::Fail,
+                    "iOS: appium binary not found on PATH",
+                )
+                .with_fix("npm install -g appium && appium driver install xcuitest"),
+            );
+        }
+    }
+
+    let chat_key_present = env::var("AI_GATEWAY_API_KEY").is_ok();
+    if chat_key_present {
+        checks.push(Check::new(
+            "providers.chat",
+            category,
+            Status::Info,
+            "AI_GATEWAY_API_KEY present (chat enabled)",
+        ));
+    } else {
+        checks.push(
+            Check::new(
+                "providers.chat",
+                category,
+                Status::Info,
+                "AI_GATEWAY_API_KEY not set (chat command disabled)",
+            )
+            .with_fix("export AI_GATEWAY_API_KEY=gw_..."),
+        );
+    }
+
+    if let Some(active) = active {
+        checks.push(Check::new(
+            "providers.active",
+            category,
+            Status::Info,
+            format!("AGENT_BROWSER_PROVIDER = {}", active),
+        ));
+    }
+}

cli/src/doctor/security.rs

@@ -0,0 +1,167 @@
+//! Check security posture: encryption key presence / permissions, saved
+//! state file age, and the optional action policy file.
+
+use std::env;
+use std::fs;
+use std::path::PathBuf;
+use std::time::{Duration, SystemTime};
+
+#[cfg(unix)]
+use std::os::unix::fs::PermissionsExt;
+
+use super::helpers::parse_json_file;
+use super::{Check, Status};
+use crate::native::state::{get_sessions_dir, get_state_dir};
+
+pub(super) fn check(checks: &mut Vec<Check>) {
+    let category = "Security";
+
+    let key_env = env::var("AGENT_BROWSER_ENCRYPTION_KEY").ok();
+    let key_file = get_state_dir().join(".encryption-key");
+    if let Some(hex) = &key_env {
+        if hex.len() == 64 && hex.chars().all(|c| c.is_ascii_hexdigit()) {
+            checks.push(Check::new(
+                "security.encryption_key",
+                category,
+                Status::Pass,
+                "AGENT_BROWSER_ENCRYPTION_KEY set (64-char hex)",
+            ));
+        } else {
+            checks.push(
+                Check::new(
+                    "security.encryption_key",
+                    category,
+                    Status::Fail,
+                    "AGENT_BROWSER_ENCRYPTION_KEY is not a 64-char hex string",
+                )
+                .with_fix("export AGENT_BROWSER_ENCRYPTION_KEY=$(openssl rand -hex 32)"),
+            );
+        }
+    } else if key_file.exists() {
+        let mut msg = format!("Encryption key file present: {}", key_file.display());
+        let mut status = Status::Pass;
+        let mut fix: Option<String> = None;
+        #[cfg(unix)]
+        if let Ok(meta) = fs::metadata(&key_file) {
+            let mode = meta.permissions().mode() & 0o777;
+            if mode & 0o077 != 0 {
+                status = Status::Warn;
+                msg = format!(
+                    "Encryption key file is too permissive ({:o}): {}",
+                    mode,
+                    key_file.display()
+                );
+                fix = Some(format!("chmod 600 {}", key_file.display()));
+            }
+        }
+        let mut check = Check::new("security.encryption_key", category, status, msg);
+        if let Some(f) = fix {
+            check = check.with_fix(f);
+        }
+        checks.push(check);
+    } else {
+        checks.push(
+            Check::new(
+                "security.encryption_key",
+                category,
+                Status::Info,
+                "No encryption key set (will be auto-generated on first auth save)",
+            )
+            .with_fix("export AGENT_BROWSER_ENCRYPTION_KEY=$(openssl rand -hex 32)"),
+        );
+    }
+
+    let sessions_dir = get_sessions_dir();
+    if sessions_dir.exists() {
+        let expire_days = env::var("AGENT_BROWSER_STATE_EXPIRE_DAYS")
+            .ok()
+            .and_then(|s| s.parse::<u64>().ok())
+            .unwrap_or(30);
+        let cutoff = SystemTime::now()
+            .checked_sub(Duration::from_secs(expire_days * 86_400))
+            .unwrap_or(SystemTime::UNIX_EPOCH);
+        let mut total = 0usize;
+        let mut old = 0usize;
+        if let Ok(entries) = fs::read_dir(&sessions_dir) {
+            for entry in entries.flatten() {
+                if entry.file_type().map(|t| t.is_file()).unwrap_or(false) {
+                    total += 1;
+                    if let Ok(meta) = entry.metadata() {
+                        if let Ok(modified) = meta.modified() {
+                            if modified < cutoff {
+                                old += 1;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        if total == 0 {
+            checks.push(Check::new(
+                "security.state_count",
+                category,
+                Status::Info,
+                "No saved state files",
+            ));
+        } else if old > 0 {
+            checks.push(
+                Check::new(
+                    "security.state_count",
+                    category,
+                    Status::Warn,
+                    format!(
+                        "{} state file(s) older than {} days ({} total)",
+                        old, expire_days, total
+                    ),
+                )
+                .with_fix(format!(
+                    "agent-browser state clean --older-than {}",
+                    expire_days
+                )),
+            );
+        } else {
+            checks.push(Check::new(
+                "security.state_count",
+                category,
+                Status::Pass,
+                format!("{} saved state file(s)", total),
+            ));
+        }
+    }
+
+    if let Ok(policy_path) = env::var("AGENT_BROWSER_ACTION_POLICY") {
+        let p = PathBuf::from(&policy_path);
+        if !p.exists() {
+            checks.push(
+                Check::new(
+                    "security.action_policy",
+                    category,
+                    Status::Fail,
+                    format!(
+                        "AGENT_BROWSER_ACTION_POLICY points to missing file: {}",
+                        policy_path
+                    ),
+                )
+                .with_fix("update or unset AGENT_BROWSER_ACTION_POLICY"),
+            );
+        } else {
+            match parse_json_file(&p) {
+                Ok(_) => checks.push(Check::new(
+                    "security.action_policy",
+                    category,
+                    Status::Pass,
+                    format!("Action policy: {}", policy_path),
+                )),
+                Err(e) => checks.push(
+                    Check::new(
+                        "security.action_policy",
+                        category,
+                        Status::Fail,
+                        format!("Action policy: {}: {}", policy_path, e),
+                    )
+                    .with_fix(format!("edit {}", policy_path)),
+                ),
+            }
+        }
+    }
+}

cli/src/flags.rs

@@ -771,6 +771,10 @@ pub fn clean_args(args: &[String]) -> Vec<String> {
         "--verbose",
         "-q",
         "--quiet",
+        // doctor-specific flags; harmless on other commands (ignored)
+        "--offline",
+        "--quick",
+        "--fix",
     ];
     // Global flags that always take a value (need to skip the next arg too)
     const GLOBAL_FLAGS_WITH_VALUE: &[&str] = &[

cli/src/main.rs

@@ -2,6 +2,7 @@ mod chat;
 mod color;
 mod commands;
 mod connection;
+mod doctor;
 mod flags;
 mod install;
 mod native;
@@ -20,10 +21,13 @@ use std::process::exit;
 #[cfg(windows)]
 use windows_sys::Win32::Foundation::CloseHandle;
 #[cfg(windows)]
-use windows_sys::Win32::System::Threading::{OpenProcess, PROCESS_QUERY_LIMITED_INFORMATION};
+use windows_sys::Win32::System::Threading::OpenProcess;
 
 use commands::{gen_id, parse_command, ParseError};
-use connection::{cleanup_stale_files, ensure_daemon, get_socket_dir, send_command, DaemonOptions};
+use connection::{
+    cleanup_stale_files, ensure_daemon, get_socket_dir, is_pid_alive, send_command, walk_daemons,
+    DaemonOptions,
+};
 use flags::{clean_args, parse_flags, Flags};
 use install::run_install;
 use output::{
@@ -182,46 +186,11 @@ fn run_session(args: &[String], session: &str, json_mode: bool) {
 
     match subcommand {
         Some("list") => {
-            let socket_dir = get_socket_dir();
-            let mut sessions: Vec<String> = Vec::new();
-
-            if let Ok(entries) = fs::read_dir(&socket_dir) {
-                for entry in entries.flatten() {
-                    let name = entry.file_name().to_string_lossy().to_string();
-                    // Look for pid files in socket directory
-                    if name.ends_with(".pid") {
-                        let session_name = name.strip_suffix(".pid").unwrap_or("");
-                        if !session_name.is_empty() {
-                            // Check if session is actually running
-                            let pid_path = socket_dir.join(&name);
-                            if let Ok(pid_str) = fs::read_to_string(&pid_path) {
-                                if let Ok(pid) = pid_str.trim().parse::<u32>() {
-                                    #[cfg(unix)]
-                                    let running = unsafe {
-                                        libc::kill(pid as i32, 0) == 0
-                                            || std::io::Error::last_os_error().raw_os_error()
-                                                != Some(libc::ESRCH)
-                                    };
-                                    #[cfg(windows)]
-                                    let running = unsafe {
-                                        let handle =
-                                            OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, 0, pid);
-                                        if handle != 0 {
-                                            CloseHandle(handle);
-                                            true
-                                        } else {
-                                            false
-                                        }
-                                    };
-                                    if running {
-                                        sessions.push(session_name.to_string());
-                                    }
-                                }
-                            }
-                        }
-                    }
-                }
-            }
+            let sessions: Vec<String> = walk_daemons()
+                .sessions
+                .into_iter()
+                .map(|s| s.name)
+                .collect();
 
             if json_mode {
                 println!(
@@ -262,25 +231,6 @@ fn get_dashboard_pid_path() -> std::path::PathBuf {
     get_socket_dir().join("dashboard.pid")
 }
 
-fn is_pid_alive(pid: u32) -> bool {
-    #[cfg(unix)]
-    {
-        unsafe { libc::kill(pid as i32, 0) == 0 }
-    }
-    #[cfg(windows)]
-    {
-        unsafe {
-            let handle = OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, 0, pid);
-            if handle != 0 {
-                CloseHandle(handle);
-                true
-            } else {
-                false
-            }
-        }
-    }
-}
-
 fn run_dashboard_start(port: u16, json_mode: bool) {
     let pid_path = get_dashboard_pid_path();
 
@@ -439,67 +389,15 @@ fn run_dashboard_stop(json_mode: bool) {
 }
 
 fn run_close_all(flags: &Flags) {
-    let socket_dir = get_socket_dir();
-    let mut sessions: Vec<(String, u32)> = Vec::new();
-
-    if let Ok(entries) = fs::read_dir(&socket_dir) {
-        for entry in entries.flatten() {
-            let name = entry.file_name().to_string_lossy().to_string();
-            if let Some(session_name) = name.strip_suffix(".pid") {
-                if session_name.is_empty() {
-                    continue;
-                }
-                let pid_path = socket_dir.join(&name);
-                if let Ok(pid_str) = fs::read_to_string(&pid_path) {
-                    if let Ok(pid) = pid_str.trim().parse::<u32>() {
-                        #[cfg(unix)]
-                        let running = unsafe {
-                            libc::kill(pid as i32, 0) == 0
-                                || std::io::Error::last_os_error().raw_os_error()
-                                    != Some(libc::ESRCH)
-                        };
-                        #[cfg(windows)]
-                        let running = unsafe {
-                            let handle = OpenProcess(PROCESS_QUERY_LIMITED_INFORMATION, 0, pid);
-                            if handle != 0 {
-                                CloseHandle(handle);
-                                true
-                            } else {
-                                false
-                            }
-                        };
-                        if running {
-                            sessions.push((session_name.to_string(), pid));
-                        } else {
-                            // Process is gone but stale files remain; clean them up
-                            cleanup_stale_files(session_name);
-                        }
-                    }
-                } else {
-                    // PID file exists but is unreadable; clean up stale files
-                    cleanup_stale_files(session_name);
-                }
-            }
-        }
-    }
-
-    // Also scan for orphaned .sock files without corresponding .pid files
-    #[cfg(unix)]
-    if let Ok(entries) = fs::read_dir(&socket_dir) {
-        for entry in entries.flatten() {
-            let name = entry.file_name().to_string_lossy().to_string();
-            if let Some(session_name) = name.strip_suffix(".sock") {
-                if session_name.is_empty() {
-                    continue;
-                }
-                let pid_path = socket_dir.join(format!("{}.pid", session_name));
-                if !pid_path.exists() {
-                    // Orphaned socket file with no PID file; remove it
-                    cleanup_stale_files(session_name);
-                }
-            }
-        }
-    }
+    // walk_daemons auto-cleans stale .pid / .sock / .stream sidecar files and
+    // separates out the standalone dashboard. We only want to send `close` to
+    // real session daemons; the dashboard has its own `dashboard stop`.
+    let inventory = walk_daemons();
+    let sessions: Vec<(String, u32)> = inventory
+        .sessions
+        .iter()
+        .map(|s| (s.name.clone(), s.pid))
+        .collect();
 
     if sessions.is_empty() {
         if flags.json {
@@ -652,6 +550,18 @@ fn main() {
         return;
     }
 
+    // Handle doctor separately (doesn't need daemon; spawns its own scratch
+    // session for the live launch test).
+    if clean.first().map(|s| s.as_str()) == Some("doctor") {
+        let opts = doctor::DoctorOptions {
+            offline: args.iter().any(|a| a == "--offline"),
+            quick: args.iter().any(|a| a == "--quick"),
+            fix: args.iter().any(|a| a == "--fix"),
+            json: flags.json,
+        };
+        exit(doctor::run_doctor(opts));
+    }
+
     // Handle dashboard subcommand
     if clean.first().map(|s| s.as_str()) == Some("dashboard") {
         match clean.get(1).map(|s| s.as_str()) {

cli/src/native/state.rs

@@ -714,14 +714,21 @@ pub fn dispatch_state_command(cmd: &Value) -> Option<Result<Value, String>> {
     }
 }
 
-pub fn get_sessions_dir() -> PathBuf {
+/// Return the agent-browser state root (`~/.agent-browser`, falling back to
+/// `<tempdir>/agent-browser` when the home directory can't be resolved).
+/// This is the parent of `sessions/`, auth storage, and the encryption key.
+pub fn get_state_dir() -> PathBuf {
     if let Some(home) = dirs::home_dir() {
-        home.join(".agent-browser").join("sessions")
+        home.join(".agent-browser")
     } else {
-        std::env::temp_dir().join("agent-browser").join("sessions")
+        std::env::temp_dir().join("agent-browser")
     }
 }
 
+pub fn get_sessions_dir() -> PathBuf {
+    get_state_dir().join("sessions")
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

cli/src/output.rs

@@ -2488,6 +2488,39 @@ Examples:
 "##
         }
 
+        // === Doctor ===
+        "doctor" => {
+            r##"
+agent-browser doctor - Diagnose and repair your install
+
+Usage: agent-browser doctor [options]
+
+Runs a battery of checks across environment, Chrome install, daemon state,
+config files, encryption key, providers, network reachability, and a live
+headless browser launch test.
+
+Auto-cleans stale daemon socket/pid/version sidecar files. Destructive
+repairs (reinstalling Chrome, purging old state files, generating a missing
+encryption key) are gated behind --fix.
+
+Options:
+  --offline            Skip network probes
+  --quick              Skip the live headless launch test
+  --fix                Also run destructive repairs
+  --json               JSON output
+
+Exit codes:
+  0  All checks pass (warnings OK)
+  1  At least one check failed
+
+Examples:
+  agent-browser doctor
+  agent-browser doctor --offline --quick
+  agent-browser doctor --fix
+  agent-browser doctor --json
+"##
+        }
+
         // === Dashboard ===
         "dashboard" => {
             r##"
@@ -2984,6 +3017,7 @@ Setup:
   install                    Install browser binaries
   install --with-deps        Also install system dependencies (Linux)
   upgrade                    Upgrade to the latest version
+  doctor [--fix]             Diagnose install; auto-clean stale files
   dashboard start            Start the observability dashboard
   profiles                   List available Chrome profiles