diff --git a/metrics.rs b/metrics.rs
index 04638fe..619e957 100644
--- a/metrics.rs
+++ b/metrics.rs
@@ -7,44 +7,85 @@
 //! - Repository count
 //! - Cache hits / misses
 //! - Error counts by error type
+//! - Git subprocess duration
+//! - Cache operation duration
+//! - Slow request detection
 //!
-//! Exposes a `/metrics` HTTP endpoint on a configurable port (default 9100).
+//! Exposes HTTP endpoints on a configurable port (default 9100):
+//! - GET /metrics          — Prometheus metrics
+//! - GET /health           — Liveness probe
+//! - GET /ready            — Readiness probe
+//! - GET /debug/log-level  — Current log level filter
+//! - PUT /debug/log-level  — Update log level filter (body: "gitks=debug")
+//! - GET /debug/config     — Runtime configuration
 
 use dashmap::DashMap;
-use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::atomic::{AtomicU64, AtomicBool, Ordering};
 use std::sync::{Arc, OnceLock};
 use std::time::{Duration, Instant};
 
 struct MetricsInner {
     /// Counter: total requests by (method, status_code)
-    /// Key: "method:status"
     request_count: DashMap<String, AtomicU64>,
-
-    /// Histogram buckets for request duration (seconds).
-    /// Each bucket: (method, le_bound_ms) → count
+    /// Histogram buckets for request duration (ms)
     duration_buckets: DashMap<String, AtomicU64>,
-
     /// Gauge: number of currently in-flight requests
     active_requests: AtomicU64,
-
     /// Gauge: total number of registered repositories
     repository_count: AtomicU64,
-
     /// Counter: cache hits
     cache_hits: AtomicU64,
-
     /// Counter: cache misses
     cache_misses: AtomicU64,
-
     /// Counter: errors by error kind
     error_count: DashMap<String, AtomicU64>,
-
-    /// Start timestamp (seconds since Unix epoch)
+    /// Start timestamp
     start_time: Instant,
+    /// Slow request threshold in ms
+    slow_request_threshold_ms: AtomicU64,
+    /// Server ready flag
+    ready: AtomicBool,
+    /// Histogram buckets for git subprocess duration (ms)
+    git_cmd_duration_buckets: DashMap<String, AtomicU64>,
+    /// Counter: git subprocess calls by command
+    git_cmd_count: DashMap<String, AtomicU64>,
+    /// Histogram buckets for cache operation duration (ms)
+    cache_op_duration_buckets: DashMap<String, AtomicU64>,
+    /// Counter: cache operations by (cache, result)
+    cache_op_count: DashMap<String, AtomicU64>,
+    /// Histogram: hook execution duration (ms)
+    hook_duration_buckets: DashMap<String, AtomicU64>,
+    /// Counter: hook executions by (hook_type, result)
+    hook_count: DashMap<String, AtomicU64>,
+    /// Counter: slow requests by method
+    slow_request_count: DashMap<String, AtomicU64>,
+
+    raft_term: AtomicU64,
+    /// Gauge: current Raft commit index
+    raft_commit_index: AtomicU64,
+    /// Gauge: current Raft last applied index
+    raft_last_applied: AtomicU64,
+    /// Gauge: whether this node is the Raft leader (1 = yes, 0 = no)
+    raft_is_leader: AtomicU64,
+    /// Gauge: number of entries in the Raft log
+    raft_log_entries: AtomicU64,
+    /// Counter: total AppendEntries RPCs sent
+    raft_append_entries_total: AtomicU64,
+    /// Counter: successful AppendEntries RPCs
+    raft_append_entries_success: AtomicU64,
+    /// Counter: total elections triggered
+    raft_elections_total: AtomicU64,
+    /// Counter: elections won
+    raft_elections_won: AtomicU64,
 }
 
 static METRICS: OnceLock<Arc<MetricsInner>> = OnceLock::new();
 
+/// Handle for dynamic log level reload.
+static LOG_RELOAD_HANDLE: OnceLock<Option<tracing_subscriber::reload::Handle<EnvFilter, tracing_subscriber::Registry>>> = OnceLock::new();
+
+use tracing_subscriber::EnvFilter;
+
 fn metrics() -> &'static Arc<MetricsInner> {
     METRICS.get_or_init(|| {
         Arc::new(MetricsInner {
@@ -56,6 +97,25 @@ fn metrics() -> &'static Arc<MetricsInner> {
             cache_misses: AtomicU64::new(0),
             error_count: DashMap::new(),
             start_time: Instant::now(),
+            slow_request_threshold_ms: AtomicU64::new(5000),
+            ready: AtomicBool::new(false),
+            git_cmd_duration_buckets: DashMap::new(),
+            git_cmd_count: DashMap::new(),
+            cache_op_duration_buckets: DashMap::new(),
+            cache_op_count: DashMap::new(),
+            hook_duration_buckets: DashMap::new(),
+            hook_count: DashMap::new(),
+            slow_request_count: DashMap::new(),
+            // Raft metrics
+            raft_term: AtomicU64::new(0),
+            raft_commit_index: AtomicU64::new(0),
+            raft_last_applied: AtomicU64::new(0),
+            raft_is_leader: AtomicU64::new(0),
+            raft_log_entries: AtomicU64::new(0),
+            raft_append_entries_total: AtomicU64::new(0),
+            raft_append_entries_success: AtomicU64::new(0),
+            raft_elections_total: AtomicU64::new(0),
+            raft_elections_won: AtomicU64::new(0),
         })
     })
 }
@@ -68,22 +128,11 @@ const DURATION_BUCKET_MS: &[u64] = &[
 
 const BUCKET_INF: u64 = u64::MAX;
 
-/// Record a request.
-pub fn record_request(method: &str, status_code: &str, duration: Duration) {
-    let m = metrics();
-    let key = format!("{method}:{status_code}");
-    m.request_count
-        .entry(key)
-        .or_insert_with(|| AtomicU64::new(0))
-        .value()
-        .fetch_add(1, Ordering::Relaxed);
-
-    let duration_ms = duration.as_millis() as u64;
+fn record_duration_bucket(map: &DashMap<String, AtomicU64>, key_prefix: &str, duration_ms: u64) {
     for &bound_ms in DURATION_BUCKET_MS {
         if duration_ms <= bound_ms || bound_ms == BUCKET_INF {
-            let bucket_key = format!("{method}:{bound_ms}");
-            m.duration_buckets
-                .entry(bucket_key)
+            let bucket_key = format!("{key_prefix}:{bound_ms}");
+            map.entry(bucket_key)
                 .or_insert_with(|| AtomicU64::new(0))
                 .value()
                 .fetch_add(1, Ordering::Relaxed);
@@ -91,32 +140,67 @@ pub fn record_request(method: &str, status_code: &str, duration: Duration) {
     }
 }
 
-/// Increment the active request gauge.
+pub fn set_slow_request_threshold(ms: u64) {
+    metrics().slow_request_threshold_ms.store(ms, Ordering::Relaxed);
+}
+
+pub fn set_ready(ready: bool) {
+    metrics().ready.store(ready, Ordering::Relaxed);
+}
+
+pub fn set_log_reload_handle(
+    handle: tracing_subscriber::reload::Handle<EnvFilter, tracing_subscriber::Registry>,
+) {
+    LOG_RELOAD_HANDLE.set(Some(handle)).ok();
+}
+
+/// Record a gRPC request.
+pub fn record_request(method: &str, status_code: &str, duration: Duration) {
+    let m = metrics();
+    let duration_ms = duration.as_millis() as u64;
+
+    // Request count
+    let key = format!("{method}:{status_code}");
+    m.request_count
+        .entry(key)
+        .or_insert_with(|| AtomicU64::new(0))
+        .value()
+        .fetch_add(1, Ordering::Relaxed);
+
+    // Duration histogram
+    record_duration_bucket(&m.duration_buckets, method, duration_ms);
+
+    // Slow request detection
+    let threshold = m.slow_request_threshold_ms.load(Ordering::Relaxed);
+    if threshold > 0 && duration_ms >= threshold {
+        m.slow_request_count
+            .entry(method.to_string())
+            .or_insert_with(|| AtomicU64::new(0))
+            .value()
+            .fetch_add(1, Ordering::Relaxed);
+    }
+}
+
 pub fn inc_active_requests() {
     metrics().active_requests.fetch_add(1, Ordering::Relaxed);
 }
 
-/// Decrement the active request gauge.
 pub fn dec_active_requests() {
     metrics().active_requests.fetch_sub(1, Ordering::Relaxed);
 }
 
-/// Set the repository count.
 pub fn set_repository_count(count: u64) {
     metrics().repository_count.store(count, Ordering::Relaxed);
 }
 
-/// Record a cache hit.
 pub fn inc_cache_hits(count: u64) {
     metrics().cache_hits.fetch_add(count, Ordering::Relaxed);
 }
 
-/// Record a cache miss.
 pub fn inc_cache_misses(count: u64) {
     metrics().cache_misses.fetch_add(count, Ordering::Relaxed);
 }
 
-/// Record an error by kind (e.g., "not_found", "internal", "invalid_argument").
 pub fn inc_error(kind: &str) {
     metrics()
         .error_count
@@ -126,62 +210,156 @@ pub fn inc_error(kind: &str) {
         .fetch_add(1, Ordering::Relaxed);
 }
 
-/// Render all metrics in Prometheus text exposition format.
+/// Record a git subprocess execution.
+pub fn record_git_cmd(command: &str, duration: Duration) {
+    let m = metrics();
+    let duration_ms = duration.as_millis() as u64;
+
+    m.git_cmd_count
+        .entry(command.to_string())
+        .or_insert_with(|| AtomicU64::new(0))
+        .value()
+        .fetch_add(1, Ordering::Relaxed);
+
+    record_duration_bucket(&m.git_cmd_duration_buckets, command, duration_ms);
+}
+
+/// Record a cache operation.
+pub fn record_cache_op(cache: &str, result: &str, duration: Duration) {
+    let m = metrics();
+    let duration_ms = duration.as_millis() as u64;
+    let key = format!("{cache}:{result}");
+
+    m.cache_op_count
+        .entry(key)
+        .or_insert_with(|| AtomicU64::new(0))
+        .value()
+        .fetch_add(1, Ordering::Relaxed);
+
+    record_duration_bucket(&m.cache_op_duration_buckets, cache, duration_ms);
+}
+
+/// Record a hook execution.
+pub fn record_hook_execution(hook_type: &str, result: &str, duration: Duration) {
+    let m = metrics();
+    let duration_ms = duration.as_millis() as u64;
+    let key = format!("{hook_type}:{result}");
+
+    m.hook_count
+        .entry(key)
+        .or_insert_with(|| AtomicU64::new(0))
+        .value()
+        .fetch_add(1, Ordering::Relaxed);
+
+    record_duration_bucket(&m.hook_duration_buckets, hook_type, duration_ms);
+}
+
+pub fn set_raft_state(term: u64, commit_index: u64, last_applied: u64, is_leader: bool, log_entries: u64) {
+    let m = metrics();
+    m.raft_term.store(term, Ordering::Relaxed);
+    m.raft_commit_index.store(commit_index, Ordering::Relaxed);
+    m.raft_last_applied.store(last_applied, Ordering::Relaxed);
+    m.raft_is_leader.store(if is_leader { 1 } else { 0 }, Ordering::Relaxed);
+    m.raft_log_entries.store(log_entries, Ordering::Relaxed);
+}
+
+/// Record an AppendEntries RPC attempt.
+pub fn inc_raft_append_entries(success: bool) {
+    let m = metrics();
+    m.raft_append_entries_total.fetch_add(1, Ordering::Relaxed);
+    if success {
+        m.raft_append_entries_success.fetch_add(1, Ordering::Relaxed);
+    }
+}
+
+/// Record an election trigger.
+pub fn inc_raft_election(won: bool) {
+    let m = metrics();
+    m.raft_elections_total.fetch_add(1, Ordering::Relaxed);
+    if won {
+        m.raft_elections_won.fetch_add(1, Ordering::Relaxed);
+    }
+}
+
+/// Escape a string for use as a Prometheus label value.
+/// Replaces `\` → `\\`, `"` → `\"`, `\n` → `\n` per the Prometheus spec.
+fn prom_escape(value: &str) -> String {
+    let mut out = String::with_capacity(value.len());
+    for ch in value.chars() {
+        match ch {
+            '\\' => out.push_str("\\\\"),
+            '"' => out.push_str("\\\""),
+            '\n' => out.push_str("\\n"),
+            _ => out.push(ch),
+        }
+    }
+    out
+}
+
+fn render_counter_map(out: &mut String, name: &str, help: &str, map: &DashMap<String, AtomicU64>, labels: &[&str]) {
+    out.push_str(&format!("# HELP {name} {help}\n"));
+    out.push_str(&format!("# TYPE {name} counter\n"));
+    for entry in map {
+        let (key, count) = (entry.key(), entry.value().load(Ordering::Relaxed));
+        let parts: Vec<&str> = key.split(':').collect();
+        if parts.len() == labels.len() {
+            let label_str: String = labels.iter().zip(parts.iter())
+                .map(|(l, v)| format!("{l}=\"{}\"", prom_escape(v)))
+                .collect::<Vec<_>>()
+                .join(",");
+            out.push_str(&format!("{name}{{{label_str}}} {count}\n"));
+        }
+    }
+    out.push('\n');
+}
+
+fn render_histogram(out: &mut String, name: &str, help: &str, map: &DashMap<String, AtomicU64>) {
+    out.push_str(&format!("# HELP {name} {help}\n"));
+    out.push_str(&format!("# TYPE {name} histogram\n"));
+    for entry in map {
+        let (key_and_bound, count) = (entry.key(), entry.value().load(Ordering::Relaxed));
+        if let Some((key, bound_str)) = key_and_bound.rsplit_once(':') {
+            let le = if bound_str.parse::<u64>() == Ok(BUCKET_INF) {
+                "+Inf".to_string()
+            } else {
+                bound_str.to_string()
+            };
+            out.push_str(&format!("{name}_bucket{{method=\"{}\",le=\"{le}\"}} {count}\n", prom_escape(key)));
+        }
+    }
+    out.push('\n');
+}
+
 pub fn render_metrics() -> String {
     let m = metrics();
-    let mut out = String::with_capacity(4096);
+    let mut out = String::with_capacity(8192);
 
-    // Header
     let uptime = m.start_time.elapsed().as_secs();
     out.push_str("# HELP gitks_uptime_seconds Time since gitks started\n");
     out.push_str("# TYPE gitks_uptime_seconds gauge\n");
     out.push_str(&format!("gitks_uptime_seconds {uptime}\n\n"));
 
-    // Active requests
     let active = m.active_requests.load(Ordering::Relaxed);
     out.push_str("# HELP gitks_active_requests Currently in-flight requests\n");
     out.push_str("# TYPE gitks_active_requests gauge\n");
     out.push_str(&format!("gitks_active_requests {active}\n\n"));
 
-    // Repository count
     let repos = m.repository_count.load(Ordering::Relaxed);
     out.push_str("# HELP gitks_repository_count Number of registered repositories\n");
     out.push_str("# TYPE gitks_repository_count gauge\n");
     out.push_str(&format!("gitks_repository_count {repos}\n\n"));
 
-    // Request count
-    out.push_str("# HELP gitks_requests_total Total gRPC requests by method and status\n");
-    out.push_str("# TYPE gitks_requests_total counter\n");
-    for entry in &m.request_count {
-        let (method_and_status, count) = (entry.key(), entry.value());
-        let count = count.load(Ordering::Relaxed);
-        if let Some((method, status)) = method_and_status.rsplit_once(':') {
-            out.push_str(&format!(
-                "gitks_requests_total{{method=\"{method}\",status=\"{status}\"}} {count}\n"
-            ));
-        }
-    }
-    out.push('\n');
+    // gRPC requests
+    render_counter_map(&mut out, "gitks_requests_total",
+        "Total gRPC requests by method and status", &m.request_count, &["method", "status"]);
 
-    // Duration histogram
-    out.push_str("# HELP gitks_request_duration_milliseconds Request duration histogram in ms\n");
-    out.push_str("# TYPE gitks_request_duration_milliseconds histogram\n");
-    for entry in &m.duration_buckets {
-        let (method_and_bound, count) = (entry.key(), entry.value());
-        let count = count.load(Ordering::Relaxed);
-        if let Some((method, bound_str)) = method_and_bound.rsplit_once(':') {
-            let bound = bound_str;
-            let le = if bound_str.parse::<u64>() == Ok(BUCKET_INF) {
-                "+Inf".to_string()
-            } else {
-                bound.to_string()
-            };
-            out.push_str(
-                &format!("gitks_request_duration_milliseconds_bucket{{method=\"{method}\",le=\"{le}\"}} {count}\n"),
-            );
-        }
-    }
-    out.push('\n');
+    // gRPC duration
+    render_histogram(&mut out, "gitks_request_duration_milliseconds",
+        "Request duration histogram in ms", &m.duration_buckets);
+
+    // Slow requests
+    render_counter_map(&mut out, "gitks_slow_requests_total",
+        "Slow gRPC requests by method", &m.slow_request_count, &["method"]);
 
     // Cache
     let hits = m.cache_hits.load(Ordering::Relaxed);
@@ -194,75 +372,263 @@ pub fn render_metrics() -> String {
     out.push_str(&format!("gitks_cache_misses_total {misses}\n\n"));
 
     // Errors
-    out.push_str("# HELP gitks_errors_total Total errors by kind\n");
-    out.push_str("# TYPE gitks_errors_total counter\n");
-    for entry in &m.error_count {
-        let (kind, count) = (entry.key(), entry.value());
-        let count = count.load(Ordering::Relaxed);
-        out.push_str(&format!("gitks_errors_total{{kind=\"{kind}\"}} {count}\n"));
-    }
-    out.push('\n');
+    render_counter_map(&mut out, "gitks_errors_total",
+        "Total errors by kind", &m.error_count, &["kind"]);
+
+    // Git subprocess
+    render_counter_map(&mut out, "gitks_git_cmd_total",
+        "Git subprocess calls by command", &m.git_cmd_count, &["command"]);
+    render_histogram(&mut out, "gitks_git_cmd_duration_milliseconds",
+        "Git subprocess duration in ms", &m.git_cmd_duration_buckets);
+
+    // Cache operations
+    render_counter_map(&mut out, "gitks_cache_ops_total",
+        "Cache operations by cache and result", &m.cache_op_count, &["cache", "result"]);
+    render_histogram(&mut out, "gitks_cache_op_duration_milliseconds",
+        "Cache operation duration in ms", &m.cache_op_duration_buckets);
+
+    // Hook execution
+    render_counter_map(&mut out, "gitks_hook_executions_total",
+        "Hook executions by type and result", &m.hook_count, &["hook_type", "result"]);
+    render_histogram(&mut out, "gitks_hook_duration_milliseconds",
+        "Hook execution duration in ms", &m.hook_duration_buckets);
+
+    // Raft consensus metrics
+    let raft_term = m.raft_term.load(Ordering::Relaxed);
+    let raft_commit = m.raft_commit_index.load(Ordering::Relaxed);
+    let raft_applied = m.raft_last_applied.load(Ordering::Relaxed);
+    let raft_leader = m.raft_is_leader.load(Ordering::Relaxed);
+    let raft_entries = m.raft_log_entries.load(Ordering::Relaxed);
+    let raft_ae_total = m.raft_append_entries_total.load(Ordering::Relaxed);
+    let raft_ae_success = m.raft_append_entries_success.load(Ordering::Relaxed);
+    let raft_elections = m.raft_elections_total.load(Ordering::Relaxed);
+    let raft_elections_won = m.raft_elections_won.load(Ordering::Relaxed);
+
+    out.push_str("# HELP gitks_raft_term Current Raft term\n");
+    out.push_str("# TYPE gitks_raft_term gauge\n");
+    out.push_str(&format!("gitks_raft_term {raft_term}\n\n"));
+
+    out.push_str("# HELP gitks_raft_commit_index Current Raft commit index\n");
+    out.push_str("# TYPE gitks_raft_commit_index gauge\n");
+    out.push_str(&format!("gitks_raft_commit_index {raft_commit}\n\n"));
+
+    out.push_str("# HELP gitks_raft_last_applied Current Raft last applied index\n");
+    out.push_str("# TYPE gitks_raft_last_applied gauge\n");
+    out.push_str(&format!("gitks_raft_last_applied {raft_applied}\n\n"));
+
+    out.push_str("# HELP gitks_raft_is_leader Whether this node is the Raft leader\n");
+    out.push_str("# TYPE gitks_raft_is_leader gauge\n");
+    out.push_str(&format!("gitks_raft_is_leader {raft_leader}\n\n"));
+
+    out.push_str("# HELP gitks_raft_log_entries Number of entries in the Raft log\n");
+    out.push_str("# TYPE gitks_raft_log_entries gauge\n");
+    out.push_str(&format!("gitks_raft_log_entries {raft_entries}\n\n"));
+
+    out.push_str("# HELP gitks_raft_append_entries_total Total AppendEntries RPCs sent\n");
+    out.push_str("# TYPE gitks_raft_append_entries_total counter\n");
+    out.push_str(&format!("gitks_raft_append_entries_total {raft_ae_total}\n\n"));
+
+    out.push_str("# HELP gitks_raft_append_entries_success Successful AppendEntries RPCs\n");
+    out.push_str("# TYPE gitks_raft_append_entries_success counter\n");
+    out.push_str(&format!("gitks_raft_append_entries_success {raft_ae_success}\n\n"));
+
+    out.push_str("# HELP gitks_raft_elections_total Total elections triggered\n");
+    out.push_str("# TYPE gitks_raft_elections_total counter\n");
+    out.push_str(&format!("gitks_raft_elections_total {raft_elections}\n\n"));
+
+    out.push_str("# HELP gitks_raft_elections_won Elections won by this node\n");
+    out.push_str("# TYPE gitks_raft_elections_won counter\n");
+    out.push_str(&format!("gitks_raft_elections_won {raft_elections_won}\n\n"));
 
     out
 }
 
-/// Start the metrics HTTP server on the given port.
-/// Runs in a background task; returns the JoinHandle.
+use bytes::Bytes;
+use http_body_util::Full;
+use hyper::body::Incoming;
+use hyper::{Request, Response, Method};
+use hyper::service::Service;
+use std::convert::Infallible;
+use std::future::Future;
+use std::pin::Pin;
+use std::net::SocketAddr;
+
+/// Global cancel token for the HTTP server, set from main.
+static HTTP_CANCEL: OnceLock<tokio_util::sync::CancellationToken> = OnceLock::new();
+
+pub fn set_http_cancel_token(token: tokio_util::sync::CancellationToken) {
+    HTTP_CANCEL.set(token).ok();
+}
+
+struct Router;
+
+impl Service<Request<Incoming>> for Router {
+    type Response = Response<Full<Bytes>>;
+    type Error = Infallible;
+    type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>;
+
+    fn call(&self, req: Request<Incoming>) -> Self::Future {
+        Box::pin(handle_request(req))
+    }
+}
+
+fn json_response(status: u16, body: &str) -> Response<Full<Bytes>> {
+    Response::builder()
+        .status(status)
+        .header("Content-Type", "application/json")
+        .header("Connection", "close")
+        .body(Full::new(Bytes::from(body.to_string())))
+        .unwrap()
+}
+
+fn text_response(status: u16, content_type: &str, body: String) -> Response<Full<Bytes>> {
+    Response::builder()
+        .status(status)
+        .header("Content-Type", content_type)
+        .header("Connection", "close")
+        .body(Full::new(Bytes::from(body)))
+        .unwrap()
+}
+
+async fn handle_request(req: Request<Incoming>) -> Result<Response<Full<Bytes>>, Infallible> {
+    let method = req.method().clone();
+    let path = req.uri().path().to_owned();
+
+    tracing::debug!(%method, %path, "HTTP request");
+
+    let response = match (method, path.as_str()) {
+        (Method::GET, "/metrics") => {
+            let body = render_metrics();
+            text_response(200, "text/plain; version=0.0.4; charset=utf-8", body)
+        }
+        (Method::GET, "/health") => {
+            json_response(200, r#"{"status":"healthy"}"#)
+        }
+        (Method::GET, "/ready") => {
+            if metrics().ready.load(Ordering::Relaxed) {
+                json_response(200, r#"{"status":"ready"}"#)
+            } else {
+                json_response(503, r#"{"status":"not_ready"}"#)
+            }
+        }
+        (Method::GET, "/debug/log-level") => {
+            let msg = if LOG_RELOAD_HANDLE.get().is_some() {
+                "use PUT to change"
+            } else {
+                "dynamic log level not available"
+            };
+            json_response(200, &format!(r#"{{"log_level":"{msg}"}}"#))
+        }
+        (Method::PUT, "/debug/log-level") => {
+            match handle_log_level_update(req).await {
+                Ok(resp) => resp,
+                Err(e) => json_response(400, &format!(r#"{{"error":"{e}"}}"#)),
+            }
+        }
+        (Method::GET, "/debug/config") => {
+            let threshold = metrics().slow_request_threshold_ms.load(Ordering::Relaxed);
+            let ready = metrics().ready.load(Ordering::Relaxed);
+            json_response(200, &format!(
+                r#"{{"slow_request_threshold_ms":{},"ready":{}}}"#, threshold, ready
+            ))
+        }
+        _ => {
+            json_response(404, r#"{"error":"not found"}"#)
+        }
+    };
+
+    Ok(response)
+}
+
+async fn handle_log_level_update(
+    req: Request<Incoming>,
+) -> Result<Response<Full<Bytes>>, String> {
+    use http_body_util::BodyExt;
+
+    let body_bytes = req
+        .collect()
+        .await
+        .map_err(|e| format!("failed to read body: {e}"))?
+        .to_bytes();
+
+    let new_filter = String::from_utf8(body_bytes.to_vec())
+        .map_err(|e| format!("invalid UTF-8: {e}"))?;
+    let new_filter = new_filter.trim().to_string();
+
+    if new_filter.is_empty() {
+        return Ok(json_response(400, r#"{"error":"empty filter"}"#));
+    }
+
+    match LOG_RELOAD_HANDLE.get() {
+        Some(Some(handle)) => match new_filter.parse::<EnvFilter>() {
+            Ok(filter) => {
+                if let Err(e) = handle.reload(filter) {
+                    Ok(json_response(500, &format!(r#"{{"error":"{e}"}}"#)))
+                } else {
+                    tracing::info!(new_filter = %new_filter, "log level updated via HTTP");
+                    Ok(json_response(200, &format!(
+                        r#"{{"status":"ok","filter":"{}"}}"#, new_filter
+                    )))
+                }
+            }
+            Err(e) => Ok(json_response(400, &format!(
+                r#"{{"error":"invalid filter: {e}"}}"#
+            ))),
+        },
+        _ => Ok(json_response(501, r#"{"error":"dynamic log level not configured"}"#)),
+    }
+}
+
+/// Start the HTTP server (metrics + health + debug) using hyper 1.x.
 pub fn start_metrics_server(port: u16) -> tokio::task::JoinHandle<()> {
     tokio::spawn(async move {
-        let listener = match tokio::net::TcpListener::bind(format!("0.0.0.0:{port}")).await {
+        let listener = match tokio::net::TcpListener::bind(SocketAddr::from(([0, 0, 0, 0], port)))
+            .await
+        {
             Ok(l) => l,
             Err(e) => {
-                tracing::error!(port, error = %e, "failed to bind metrics server");
+                tracing::error!(port, error = %e, "failed to bind HTTP server");
                 return;
             }
         };
-        tracing::info!(port, "metrics HTTP server started");
+        tracing::info!(port, "HTTP server started (metrics + health + debug)");
+
+        let cancel = HTTP_CANCEL
+            .get()
+            .cloned()
+            .unwrap_or_else(tokio_util::sync::CancellationToken::new);
 
         loop {
-            match listener.accept().await {
-                Ok((socket, peer)) => {
-                    tracing::debug!(%peer, "metrics request");
-                    tokio::spawn(handle_metrics_connection(socket));
+            tokio::select! {
+                result = listener.accept() => {
+                    match result {
+                        Ok((stream, _peer)) => {
+                            let io = hyper_util::rt::TokioIo::new(stream);
+                            tokio::spawn(async move {
+                                let builder = hyper::server::conn::http1::Builder::new();
+                                if let Err(e) = builder
+                                    .serve_connection(io, Router)
+                                    .with_upgrades()
+                                    .await
+                                {
+                                    tracing::debug!(error = %e, "HTTP connection error");
+                                }
+                            });
+                        }
+                        Err(e) => {
+                            tracing::error!(error = %e, "HTTP accept error");
+                        }
+                    }
                 }
-                Err(e) => {
-                    tracing::error!(error = %e, "metrics accept error");
+                _ = cancel.cancelled() => {
+                    tracing::info!("HTTP server shutting down");
+                    break;
                 }
             }
         }
     })
 }
 
-async fn handle_metrics_connection(mut socket: tokio::net::TcpStream) {
-    use tokio::io::{AsyncReadExt, AsyncWriteExt};
-
-    let mut buf = [0u8; 4096];
-    let _ = tokio::time::timeout(Duration::from_secs(5), socket.read(&mut buf)).await;
-
-    let body = render_metrics();
-    let response = format!(
-        "HTTP/1.1 200 OK\r\nContent-Type: text/plain; version=0.0.4\r\nContent-Length: {}\r\nConnection: close\r\n\r\n{}",
-        body.len(),
-        body
-    );
-
-    let _ = tokio::time::timeout(
-        Duration::from_secs(5),
-        socket.write_all(response.as_bytes()),
-    )
-    .await;
-    let _ = socket.shutdown().await;
-}
-
-/// A guard that records metrics on drop.
-///
-/// Usage in handlers:
-/// ```ignore
-/// let m = crate::metrics::RequestMetrics::new("Service/Method");
-/// // ... handle request ...
-/// m.record("ok"); // on success
-/// // m.record("internal"); // or on error, with tonic error kind
-/// ```
 pub struct RequestMetrics {
     method: &'static str,
     start: Instant,
@@ -280,7 +646,20 @@ impl RequestMetrics {
     /// Record the outcome. Idempotent — safe to call before each return.
     pub fn record(&self, status: &str) {
         let duration = self.start.elapsed();
+        let duration_ms = duration.as_millis() as u64;
         record_request(self.method, status, duration);
+
+        // Slow request warning
+        let threshold = metrics().slow_request_threshold_ms.load(Ordering::Relaxed);
+        if threshold > 0 && duration_ms >= threshold {
+            tracing::warn!(
+                method = self.method,
+                status,
+                elapsed_ms = duration_ms,
+                threshold_ms = threshold,
+                "slow gRPC request detected"
+            );
+        }
     }
 }