diff --git a/src/agent/loop_.rs b/src/agent/loop_.rs
index 57f983c..54b88f4 100644
--- a/src/agent/loop_.rs
+++ b/src/agent/loop_.rs
@@ -40,7 +40,8 @@ pub async fn run(
     // ── Wire up agnostic subsystems ──────────────────────────────
     let observer: Arc<dyn Observer> =
         Arc::from(observability::create_observer(&config.observability));
-    let _runtime = runtime::create_runtime(&config.runtime)?;
+    let runtime: Arc<dyn runtime::RuntimeAdapter> =
+        Arc::from(runtime::create_runtime(&config.runtime)?);
     let security = Arc::new(SecurityPolicy::from_config(
         &config.autonomy,
         &config.workspace_dir,
@@ -60,7 +61,13 @@ pub async fn run(
     } else {
         None
     };
-    let _tools = tools::all_tools(&security, mem.clone(), composio_key, &config.browser);
+    let _tools = tools::all_tools_with_runtime(
+        &security,
+        runtime,
+        mem.clone(),
+        composio_key,
+        &config.browser,
+    );
 
     // ── Resolve provider ─────────────────────────────────────────
     let provider_name = provider_override
diff --git a/src/config/mod.rs b/src/config/mod.rs
index e5a6521..b442538 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -2,7 +2,7 @@ pub mod schema;
 
 pub use schema::{
     AutonomyConfig, BrowserConfig, ChannelsConfig, ComposioConfig, Config, DiscordConfig,
-    GatewayConfig, HeartbeatConfig, IMessageConfig, IdentityConfig, MatrixConfig, MemoryConfig,
-    ModelRouteConfig, ObservabilityConfig, ReliabilityConfig, RuntimeConfig, SecretsConfig,
-    SlackConfig, TelegramConfig, TunnelConfig, WebhookConfig,
+    DockerRuntimeConfig, GatewayConfig, HeartbeatConfig, IMessageConfig, IdentityConfig,
+    MatrixConfig, MemoryConfig, ModelRouteConfig, ObservabilityConfig, ReliabilityConfig,
+    RuntimeConfig, SecretsConfig, SlackConfig, TelegramConfig, TunnelConfig, WebhookConfig,
 };
diff --git a/src/config/schema.rs b/src/config/schema.rs
index 764ba69..a866880 100644
--- a/src/config/schema.rs
+++ b/src/config/schema.rs
@@ -2,8 +2,9 @@ use crate::security::AutonomyLevel;
 use anyhow::{Context, Result};
 use directories::UserDirs;
 use serde::{Deserialize, Serialize};
-use std::fs;
-use std::path::PathBuf;
+use std::fs::{self, File, OpenOptions};
+use std::io::Write;
+use std::path::{Path, PathBuf};
 
 // ── Top-level config ──────────────────────────────────────────────
 
@@ -112,6 +113,18 @@ pub struct GatewayConfig {
     /// Paired bearer tokens (managed automatically, not user-edited)
     #[serde(default)]
     pub paired_tokens: Vec<String>,
+
+    /// Max `/pair` requests per minute per client key.
+    #[serde(default = "default_pair_rate_limit")]
+    pub pair_rate_limit_per_minute: u32,
+
+    /// Max `/webhook` requests per minute per client key.
+    #[serde(default = "default_webhook_rate_limit")]
+    pub webhook_rate_limit_per_minute: u32,
+
+    /// TTL for webhook idempotency keys.
+    #[serde(default = "default_idempotency_ttl_secs")]
+    pub idempotency_ttl_secs: u64,
 }
 
 fn default_gateway_port() -> u16 {
@@ -122,6 +135,18 @@ fn default_gateway_host() -> String {
     "127.0.0.1".into()
 }
 
+fn default_pair_rate_limit() -> u32 {
+    10
+}
+
+fn default_webhook_rate_limit() -> u32 {
+    60
+}
+
+fn default_idempotency_ttl_secs() -> u64 {
+    300
+}
+
 fn default_true() -> bool {
     true
 }
@@ -134,6 +159,9 @@ impl Default for GatewayConfig {
             require_pairing: true,
             allow_public_bind: false,
             paired_tokens: Vec::new(),
+            pair_rate_limit_per_minute: default_pair_rate_limit(),
+            webhook_rate_limit_per_minute: default_webhook_rate_limit(),
+            idempotency_ttl_secs: default_idempotency_ttl_secs(),
         }
     }
 }
@@ -320,6 +348,14 @@ pub struct AutonomyConfig {
     pub forbidden_paths: Vec<String>,
     pub max_actions_per_hour: u32,
     pub max_cost_per_day_cents: u32,
+
+    /// Require explicit approval for medium-risk shell commands.
+    #[serde(default = "default_true")]
+    pub require_approval_for_medium_risk: bool,
+
+    /// Block high-risk shell commands even if allowlisted.
+    #[serde(default = "default_true")]
+    pub block_high_risk_commands: bool,
 }
 
 impl Default for AutonomyConfig {
@@ -363,6 +399,8 @@ impl Default for AutonomyConfig {
             ],
             max_actions_per_hour: 20,
             max_cost_per_day_cents: 500,
+            require_approval_for_medium_risk: true,
+            block_high_risk_commands: true,
         }
     }
 }
@@ -371,16 +409,85 @@ impl Default for AutonomyConfig {
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct RuntimeConfig {
-    /// Runtime kind (currently supported: "native").
-    ///
-    /// Reserved values (not implemented yet): "docker", "cloudflare".
+    /// Runtime kind (`native` | `docker`).
+    #[serde(default = "default_runtime_kind")]
     pub kind: String,
+
+    /// Docker runtime settings (used when `kind = "docker"`).
+    #[serde(default)]
+    pub docker: DockerRuntimeConfig,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct DockerRuntimeConfig {
+    /// Runtime image used to execute shell commands.
+    #[serde(default = "default_docker_image")]
+    pub image: String,
+
+    /// Docker network mode (`none`, `bridge`, etc.).
+    #[serde(default = "default_docker_network")]
+    pub network: String,
+
+    /// Optional memory limit in MB (`None` = no explicit limit).
+    #[serde(default = "default_docker_memory_limit_mb")]
+    pub memory_limit_mb: Option<u64>,
+
+    /// Optional CPU limit (`None` = no explicit limit).
+    #[serde(default = "default_docker_cpu_limit")]
+    pub cpu_limit: Option<f64>,
+
+    /// Mount root filesystem as read-only.
+    #[serde(default = "default_true")]
+    pub read_only_rootfs: bool,
+
+    /// Mount configured workspace into `/workspace`.
+    #[serde(default = "default_true")]
+    pub mount_workspace: bool,
+
+    /// Optional workspace root allowlist for Docker mount validation.
+    #[serde(default)]
+    pub allowed_workspace_roots: Vec<String>,
+}
+
+fn default_runtime_kind() -> String {
+    "native".into()
+}
+
+fn default_docker_image() -> String {
+    "alpine:3.20".into()
+}
+
+fn default_docker_network() -> String {
+    "none".into()
+}
+
+fn default_docker_memory_limit_mb() -> Option<u64> {
+    Some(512)
+}
+
+fn default_docker_cpu_limit() -> Option<f64> {
+    Some(1.0)
+}
+
+impl Default for DockerRuntimeConfig {
+    fn default() -> Self {
+        Self {
+            image: default_docker_image(),
+            network: default_docker_network(),
+            memory_limit_mb: default_docker_memory_limit_mb(),
+            cpu_limit: default_docker_cpu_limit(),
+            read_only_rootfs: true,
+            mount_workspace: true,
+            allowed_workspace_roots: Vec::new(),
+        }
+    }
 }
 
 impl Default for RuntimeConfig {
     fn default() -> Self {
         Self {
-            kind: "native".into(),
+            kind: default_runtime_kind(),
+            docker: DockerRuntimeConfig::default(),
         }
     }
 }
@@ -811,11 +918,86 @@ impl Config {
 
     pub fn save(&self) -> Result<()> {
         let toml_str = toml::to_string_pretty(self).context("Failed to serialize config")?;
-        fs::write(&self.config_path, toml_str).context("Failed to write config file")?;
+
+        let parent_dir = self
+            .config_path
+            .parent()
+            .context("Config path must have a parent directory")?;
+        fs::create_dir_all(parent_dir).with_context(|| {
+            format!(
+                "Failed to create config directory: {}",
+                parent_dir.display()
+            )
+        })?;
+
+        let file_name = self
+            .config_path
+            .file_name()
+            .and_then(|v| v.to_str())
+            .unwrap_or("config.toml");
+        let temp_path = parent_dir.join(format!(".{file_name}.tmp-{}", uuid::Uuid::new_v4()));
+        let backup_path = parent_dir.join(format!("{file_name}.bak"));
+
+        let mut temp_file = OpenOptions::new()
+            .create_new(true)
+            .write(true)
+            .open(&temp_path)
+            .with_context(|| {
+                format!(
+                    "Failed to create temporary config file: {}",
+                    temp_path.display()
+                )
+            })?;
+        temp_file
+            .write_all(toml_str.as_bytes())
+            .context("Failed to write temporary config contents")?;
+        temp_file
+            .sync_all()
+            .context("Failed to fsync temporary config file")?;
+        drop(temp_file);
+
+        let had_existing_config = self.config_path.exists();
+        if had_existing_config {
+            fs::copy(&self.config_path, &backup_path).with_context(|| {
+                format!(
+                    "Failed to create config backup before atomic replace: {}",
+                    backup_path.display()
+                )
+            })?;
+        }
+
+        if let Err(e) = fs::rename(&temp_path, &self.config_path) {
+            let _ = fs::remove_file(&temp_path);
+            if had_existing_config && backup_path.exists() {
+                let _ = fs::copy(&backup_path, &self.config_path);
+            }
+            anyhow::bail!("Failed to atomically replace config file: {e}");
+        }
+
+        sync_directory(parent_dir)?;
+
+        if had_existing_config {
+            let _ = fs::remove_file(&backup_path);
+        }
+
         Ok(())
     }
 }
 
+#[cfg(unix)]
+fn sync_directory(path: &Path) -> Result<()> {
+    let dir = File::open(path)
+        .with_context(|| format!("Failed to open directory for fsync: {}", path.display()))?;
+    dir.sync_all()
+        .with_context(|| format!("Failed to fsync directory metadata: {}", path.display()))?;
+    Ok(())
+}
+
+#[cfg(not(unix))]
+fn sync_directory(_path: &Path) -> Result<()> {
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -850,12 +1032,20 @@ mod tests {
         assert!(a.forbidden_paths.contains(&"/etc".to_string()));
         assert_eq!(a.max_actions_per_hour, 20);
         assert_eq!(a.max_cost_per_day_cents, 500);
+        assert!(a.require_approval_for_medium_risk);
+        assert!(a.block_high_risk_commands);
     }
 
     #[test]
     fn runtime_config_default() {
         let r = RuntimeConfig::default();
         assert_eq!(r.kind, "native");
+        assert_eq!(r.docker.image, "alpine:3.20");
+        assert_eq!(r.docker.network, "none");
+        assert_eq!(r.docker.memory_limit_mb, Some(512));
+        assert_eq!(r.docker.cpu_limit, Some(1.0));
+        assert!(r.docker.read_only_rootfs);
+        assert!(r.docker.mount_workspace);
     }
 
     #[test]
@@ -905,9 +1095,12 @@ mod tests {
                 forbidden_paths: vec!["/secret".into()],
                 max_actions_per_hour: 50,
                 max_cost_per_day_cents: 1000,
+                require_approval_for_medium_risk: false,
+                block_high_risk_commands: true,
             },
             runtime: RuntimeConfig {
                 kind: "docker".into(),
+                ..RuntimeConfig::default()
             },
             reliability: ReliabilityConfig::default(),
             model_routes: Vec::new(),
@@ -1022,6 +1215,38 @@ default_temperature = 0.7
         let _ = fs::remove_dir_all(&dir);
     }
 
+
+    #[test]
+    fn config_save_atomic_cleanup() {
+        let dir =
+            std::env::temp_dir().join(format!("zeroclaw_test_config_{}", uuid::Uuid::new_v4()));
+        fs::create_dir_all(&dir).unwrap();
+
+        let config_path = dir.join("config.toml");
+        let mut config = Config::default();
+        config.workspace_dir = dir.join("workspace");
+        config.config_path = config_path.clone();
+        config.default_model = Some("model-a".into());
+
+        config.save().unwrap();
+        assert!(config_path.exists());
+
+        config.default_model = Some("model-b".into());
+        config.save().unwrap();
+
+        let contents = fs::read_to_string(&config_path).unwrap();
+        assert!(contents.contains("model-b"));
+
+        let names: Vec<String> = fs::read_dir(&dir)
+            .unwrap()
+            .map(|entry| entry.unwrap().file_name().to_string_lossy().to_string())
+            .collect();
+        assert!(!names.iter().any(|name| name.contains(".tmp-")));
+        assert!(!names.iter().any(|name| name.ends_with(".bak")));
+
+        let _ = fs::remove_dir_all(&dir);
+    }
+
     // ── Telegram / Discord config ────────────────────────────
 
     #[test]
@@ -1343,6 +1568,9 @@ channel_id = "C123"
             g.paired_tokens.is_empty(),
             "No pre-paired tokens by default"
         );
+        assert_eq!(g.pair_rate_limit_per_minute, 10);
+        assert_eq!(g.webhook_rate_limit_per_minute, 60);
+        assert_eq!(g.idempotency_ttl_secs, 300);
     }
 
     #[test]
@@ -1368,12 +1596,18 @@ channel_id = "C123"
             require_pairing: true,
             allow_public_bind: false,
             paired_tokens: vec!["zc_test_token".into()],
+            pair_rate_limit_per_minute: 12,
+            webhook_rate_limit_per_minute: 80,
+            idempotency_ttl_secs: 600,
         };
         let toml_str = toml::to_string(&g).unwrap();
         let parsed: GatewayConfig = toml::from_str(&toml_str).unwrap();
         assert!(parsed.require_pairing);
         assert!(!parsed.allow_public_bind);
         assert_eq!(parsed.paired_tokens, vec!["zc_test_token"]);
+        assert_eq!(parsed.pair_rate_limit_per_minute, 12);
+        assert_eq!(parsed.webhook_rate_limit_per_minute, 80);
+        assert_eq!(parsed.idempotency_ttl_secs, 600);
     }
 
     #[test]
diff --git a/src/gateway/mod.rs b/src/gateway/mod.rs
index bede685..4f85437 100644
--- a/src/gateway/mod.rs
+++ b/src/gateway/mod.rs
@@ -22,9 +22,10 @@ use axum::{
     routing::{get, post},
     Router,
 };
+use std::collections::HashMap;
 use std::net::SocketAddr;
-use std::sync::Arc;
-use std::time::Duration;
+use std::sync::{Arc, Mutex};
+use std::time::{Duration, Instant};
 use tower_http::limit::RequestBodyLimitLayer;
 use tower_http::timeout::TimeoutLayer;
 
@@ -32,6 +33,118 @@ use tower_http::timeout::TimeoutLayer;
 pub const MAX_BODY_SIZE: usize = 65_536;
 /// Request timeout (30s) — prevents slow-loris attacks
 pub const REQUEST_TIMEOUT_SECS: u64 = 30;
+/// Sliding window used by gateway rate limiting.
+pub const RATE_LIMIT_WINDOW_SECS: u64 = 60;
+
+#[derive(Debug)]
+struct SlidingWindowRateLimiter {
+    limit_per_window: u32,
+    window: Duration,
+    requests: Mutex<HashMap<String, Vec<Instant>>>,
+}
+
+impl SlidingWindowRateLimiter {
+    fn new(limit_per_window: u32, window: Duration) -> Self {
+        Self {
+            limit_per_window,
+            window,
+            requests: Mutex::new(HashMap::new()),
+        }
+    }
+
+    fn allow(&self, key: &str) -> bool {
+        if self.limit_per_window == 0 {
+            return true;
+        }
+
+        let now = Instant::now();
+        let cutoff = now.checked_sub(self.window).unwrap_or_else(Instant::now);
+
+        let mut requests = self
+            .requests
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+
+        let entry = requests.entry(key.to_owned()).or_default();
+        entry.retain(|instant| *instant > cutoff);
+
+        if entry.len() >= self.limit_per_window as usize {
+            return false;
+        }
+
+        entry.push(now);
+        true
+    }
+}
+
+#[derive(Debug)]
+pub struct GatewayRateLimiter {
+    pair: SlidingWindowRateLimiter,
+    webhook: SlidingWindowRateLimiter,
+}
+
+impl GatewayRateLimiter {
+    fn new(pair_per_minute: u32, webhook_per_minute: u32) -> Self {
+        let window = Duration::from_secs(RATE_LIMIT_WINDOW_SECS);
+        Self {
+            pair: SlidingWindowRateLimiter::new(pair_per_minute, window),
+            webhook: SlidingWindowRateLimiter::new(webhook_per_minute, window),
+        }
+    }
+
+    fn allow_pair(&self, key: &str) -> bool {
+        self.pair.allow(key)
+    }
+
+    fn allow_webhook(&self, key: &str) -> bool {
+        self.webhook.allow(key)
+    }
+}
+
+#[derive(Debug)]
+pub struct IdempotencyStore {
+    ttl: Duration,
+    keys: Mutex<HashMap<String, Instant>>,
+}
+
+impl IdempotencyStore {
+    fn new(ttl: Duration) -> Self {
+        Self {
+            ttl,
+            keys: Mutex::new(HashMap::new()),
+        }
+    }
+
+    /// Returns true if this key is new and is now recorded.
+    fn record_if_new(&self, key: &str) -> bool {
+        let now = Instant::now();
+        let mut keys = self
+            .keys
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+
+        keys.retain(|_, seen_at| now.duration_since(*seen_at) < self.ttl);
+
+        if keys.contains_key(key) {
+            return false;
+        }
+
+        keys.insert(key.to_owned(), now);
+        true
+    }
+}
+
+fn client_key_from_headers(headers: &HeaderMap) -> String {
+    for header_name in ["X-Forwarded-For", "X-Real-IP"] {
+        if let Some(value) = headers.get(header_name).and_then(|v| v.to_str().ok()) {
+            let first = value.split(',').next().unwrap_or("").trim();
+            if !first.is_empty() {
+                return first.to_owned();
+            }
+        }
+    }
+    "unknown".into()
+}
 
 /// Shared state for all axum handlers
 #[derive(Clone)]
@@ -43,6 +156,8 @@ pub struct AppState {
     pub auto_save: bool,
     pub webhook_secret: Option<Arc<str>>,
     pub pairing: Arc<PairingGuard>,
+    pub rate_limiter: Arc<GatewayRateLimiter>,
+    pub idempotency_store: Arc<IdempotencyStore>,
     pub whatsapp: Option<Arc<WhatsAppChannel>>,
     /// `WhatsApp` app secret for webhook signature verification (`X-Hub-Signature-256`)
     pub whatsapp_app_secret: Option<Arc<str>>,
@@ -66,17 +181,15 @@ pub async fn run_gateway(host: &str, port: u16, config: Config) -> Result<()> {
     let actual_port = listener.local_addr()?.port();
     let display_addr = format!("{host}:{actual_port}");
 
+    let provider: Arc<dyn Provider> = Arc::from(providers::create_resilient_provider(
+        config.default_provider.as_deref().unwrap_or("openrouter"),
+        config.api_key.as_deref(),
+        &config.reliability,
+    )?);
     let model = config
         .default_model
         .clone()
         .unwrap_or_else(|| "anthropic/claude-sonnet-4-20250514".into());
-    let provider: Arc<dyn Provider> = Arc::from(providers::create_routed_provider(
-        config.default_provider.as_deref().unwrap_or("openrouter"),
-        config.api_key.as_deref(),
-        &config.reliability,
-        &config.model_routes,
-        &model,
-    )?);
     let temperature = config.default_temperature;
     let mem: Arc<dyn Memory> = Arc::from(memory::create_memory(
         &config.memory,
@@ -127,6 +240,13 @@ pub async fn run_gateway(host: &str, port: u16, config: Config) -> Result<()> {
         config.gateway.require_pairing,
         &config.gateway.paired_tokens,
     ));
+    let rate_limiter = Arc::new(GatewayRateLimiter::new(
+        config.gateway.pair_rate_limit_per_minute,
+        config.gateway.webhook_rate_limit_per_minute,
+    ));
+    let idempotency_store = Arc::new(IdempotencyStore::new(Duration::from_secs(
+        config.gateway.idempotency_ttl_secs.max(1),
+    )));
 
     // ── Tunnel ────────────────────────────────────────────────
     let tunnel = crate::tunnel::create_tunnel(&config.tunnel)?;
@@ -185,6 +305,8 @@ pub async fn run_gateway(host: &str, port: u16, config: Config) -> Result<()> {
         auto_save: config.memory.auto_save,
         webhook_secret,
         pairing,
+        rate_limiter,
+        idempotency_store,
         whatsapp: whatsapp_channel,
         whatsapp_app_secret,
     };
@@ -225,6 +347,16 @@ async fn handle_health(State(state): State<AppState>) -> impl IntoResponse {
 
 /// POST /pair — exchange one-time code for bearer token
 async fn handle_pair(State(state): State<AppState>, headers: HeaderMap) -> impl IntoResponse {
+    let client_key = client_key_from_headers(&headers);
+    if !state.rate_limiter.allow_pair(&client_key) {
+        tracing::warn!("/pair rate limit exceeded for key: {client_key}");
+        let err = serde_json::json!({
+            "error": "Too many pairing requests. Please retry later.",
+            "retry_after": RATE_LIMIT_WINDOW_SECS,
+        });
+        return (StatusCode::TOO_MANY_REQUESTS, Json(err));
+    }
+
     let code = headers
         .get("X-Pairing-Code")
         .and_then(|v| v.to_str().ok())
@@ -270,6 +402,16 @@ async fn handle_webhook(
     headers: HeaderMap,
     body: Result<Json<WebhookBody>, axum::extract::rejection::JsonRejection>,
 ) -> impl IntoResponse {
+    let client_key = client_key_from_headers(&headers);
+    if !state.rate_limiter.allow_webhook(&client_key) {
+        tracing::warn!("/webhook rate limit exceeded for key: {client_key}");
+        let err = serde_json::json!({
+            "error": "Too many webhook requests. Please retry later.",
+            "retry_after": RATE_LIMIT_WINDOW_SECS,
+        });
+        return (StatusCode::TOO_MANY_REQUESTS, Json(err));
+    }
+
     // ── Bearer token auth (pairing) ──
     if state.pairing.require_pairing() {
         let auth = headers
@@ -312,6 +454,24 @@ async fn handle_webhook(
         }
     };
 
+    // ── Idempotency (optional) ──
+    if let Some(idempotency_key) = headers
+        .get("X-Idempotency-Key")
+        .and_then(|v| v.to_str().ok())
+        .map(str::trim)
+        .filter(|value| !value.is_empty())
+    {
+        if !state.idempotency_store.record_if_new(idempotency_key) {
+            tracing::info!("Webhook duplicate ignored (idempotency key: {idempotency_key})");
+            let body = serde_json::json!({
+                "status": "duplicate",
+                "idempotent": true,
+                "message": "Request already processed for this idempotency key"
+            });
+            return (StatusCode::OK, Json(body));
+        }
+    }
+
     let message = &webhook_body.message;
 
     if state.auto_save {
@@ -508,6 +668,13 @@ async fn handle_whatsapp_message(
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::memory::{Memory, MemoryCategory, MemoryEntry};
+    use crate::providers::Provider;
+    use async_trait::async_trait;
+    use axum::http::HeaderValue;
+    use axum::response::IntoResponse;
+    use http_body_util::BodyExt;
+    use std::sync::atomic::{AtomicUsize, Ordering};
 
     #[test]
     fn security_body_limit_is_64kb() {
@@ -547,6 +714,133 @@ mod tests {
         assert_clone::<AppState>();
     }
 
+    #[test]
+    fn gateway_rate_limiter_blocks_after_limit() {
+        let limiter = GatewayRateLimiter::new(2, 2);
+        assert!(limiter.allow_pair("127.0.0.1"));
+        assert!(limiter.allow_pair("127.0.0.1"));
+        assert!(!limiter.allow_pair("127.0.0.1"));
+    }
+
+    #[test]
+    fn idempotency_store_rejects_duplicate_key() {
+        let store = IdempotencyStore::new(Duration::from_secs(30));
+        assert!(store.record_if_new("req-1"));
+        assert!(!store.record_if_new("req-1"));
+        assert!(store.record_if_new("req-2"));
+    }
+
+    #[derive(Default)]
+    struct MockMemory;
+
+    #[async_trait]
+    impl Memory for MockMemory {
+        fn name(&self) -> &str {
+            "mock"
+        }
+
+        async fn store(
+            &self,
+            _key: &str,
+            _content: &str,
+            _category: MemoryCategory,
+        ) -> anyhow::Result<()> {
+            Ok(())
+        }
+
+        async fn recall(&self, _query: &str, _limit: usize) -> anyhow::Result<Vec<MemoryEntry>> {
+            Ok(Vec::new())
+        }
+
+        async fn get(&self, _key: &str) -> anyhow::Result<Option<MemoryEntry>> {
+            Ok(None)
+        }
+
+        async fn list(
+            &self,
+            _category: Option<&MemoryCategory>,
+        ) -> anyhow::Result<Vec<MemoryEntry>> {
+            Ok(Vec::new())
+        }
+
+        async fn forget(&self, _key: &str) -> anyhow::Result<bool> {
+            Ok(false)
+        }
+
+        async fn count(&self) -> anyhow::Result<usize> {
+            Ok(0)
+        }
+
+        async fn health_check(&self) -> bool {
+            true
+        }
+    }
+
+    #[derive(Default)]
+    struct MockProvider {
+        calls: AtomicUsize,
+    }
+
+    #[async_trait]
+    impl Provider for MockProvider {
+        async fn chat_with_system(
+            &self,
+            _system_prompt: Option<&str>,
+            _message: &str,
+            _model: &str,
+            _temperature: f64,
+        ) -> anyhow::Result<String> {
+            self.calls.fetch_add(1, Ordering::SeqCst);
+            Ok("ok".into())
+        }
+    }
+
+    #[tokio::test]
+    async fn webhook_idempotency_skips_duplicate_provider_calls() {
+        let provider_impl = Arc::new(MockProvider::default());
+        let provider: Arc<dyn Provider> = provider_impl.clone();
+        let memory: Arc<dyn Memory> = Arc::new(MockMemory);
+
+        let state = AppState {
+            provider,
+            model: "test-model".into(),
+            temperature: 0.0,
+            mem: memory,
+            auto_save: false,
+            webhook_secret: None,
+            pairing: Arc::new(PairingGuard::new(false, &[])),
+            rate_limiter: Arc::new(GatewayRateLimiter::new(100, 100)),
+            idempotency_store: Arc::new(IdempotencyStore::new(Duration::from_secs(300))),
+            whatsapp: None,
+            whatsapp_app_secret: None,
+        };
+
+        let mut headers = HeaderMap::new();
+        headers.insert("X-Idempotency-Key", HeaderValue::from_static("abc-123"));
+
+        let body = Ok(Json(WebhookBody {
+            message: "hello".into(),
+        }));
+        let first = handle_webhook(State(state.clone()), headers.clone(), body)
+            .await
+            .into_response();
+        assert_eq!(first.status(), StatusCode::OK);
+
+        let body = Ok(Json(WebhookBody {
+            message: "hello".into(),
+        }));
+        let second = handle_webhook(State(state), headers, body)
+            .await
+            .into_response();
+        assert_eq!(second.status(), StatusCode::OK);
+
+        let payload = second.into_body().collect().await.unwrap().to_bytes();
+        let parsed: serde_json::Value = serde_json::from_slice(&payload).unwrap();
+        assert_eq!(parsed["status"], "duplicate");
+        assert_eq!(parsed["idempotent"], true);
+        assert_eq!(provider_impl.calls.load(Ordering::SeqCst), 1);
+    }
+
     // ══════════════════════════════════════════════════════════
     // WhatsApp Signature Verification Tests (CWE-345 Prevention)
     // ══════════════════════════════════════════════════════════
@@ -572,7 +866,11 @@ mod tests {
 
         let signature_header = compute_whatsapp_signature_header(app_secret, body);
 
-        assert!(verify_whatsapp_signature(app_secret, body, &signature_header));
+        assert!(verify_whatsapp_signature(
+            app_secret,
+            body,
+            &signature_header
+        ));
     }
 
     #[test]
@@ -583,7 +881,11 @@ mod tests {
 
         let signature_header = compute_whatsapp_signature_header(wrong_secret, body);
 
-        assert!(!verify_whatsapp_signature(app_secret, body, &signature_header));
+        assert!(!verify_whatsapp_signature(
+            app_secret,
+            body,
+            &signature_header
+        ));
     }
 
     #[test]
@@ -610,7 +912,11 @@ mod tests {
         // Signature without "sha256=" prefix
         let signature_header = "abc123def456";
 
-        assert!(!verify_whatsapp_signature(app_secret, body, signature_header));
+        assert!(!verify_whatsapp_signature(
+            app_secret,
+            body,
+            signature_header
+        ));
     }
 
     #[test]
@@ -643,7 +949,11 @@ mod tests {
 
         let signature_header = compute_whatsapp_signature_header(app_secret, body);
 
-        assert!(verify_whatsapp_signature(app_secret, body, &signature_header));
+        assert!(verify_whatsapp_signature(
+            app_secret,
+            body,
+            &signature_header
+        ));
     }
 
     #[test]
@@ -653,7 +963,11 @@ mod tests {
 
         let signature_header = compute_whatsapp_signature_header(app_secret, body);
 
-        assert!(verify_whatsapp_signature(app_secret, body, &signature_header));
+        assert!(verify_whatsapp_signature(
+            app_secret,
+            body,
+            &signature_header
+        ));
     }
 
     #[test]
@@ -663,7 +977,11 @@ mod tests {
 
         let signature_header = compute_whatsapp_signature_header(app_secret, body);
 
-        assert!(verify_whatsapp_signature(app_secret, body, &signature_header));
+        assert!(verify_whatsapp_signature(
+            app_secret,
+            body,
+            &signature_header
+        ));
     }
 
     #[test]
diff --git a/src/runtime/docker.rs b/src/runtime/docker.rs
new file mode 100644
index 0000000..eaa3d09
--- /dev/null
+++ b/src/runtime/docker.rs
@@ -0,0 +1,199 @@
+use super::traits::RuntimeAdapter;
+use crate::config::DockerRuntimeConfig;
+use anyhow::{Context, Result};
+use std::path::{Path, PathBuf};
+
+/// Docker runtime with lightweight container isolation.
+#[derive(Debug, Clone)]
+pub struct DockerRuntime {
+    config: DockerRuntimeConfig,
+}
+
+impl DockerRuntime {
+    pub fn new(config: DockerRuntimeConfig) -> Self {
+        Self { config }
+    }
+
+    fn workspace_mount_path(&self, workspace_dir: &Path) -> Result<PathBuf> {
+        let resolved = workspace_dir
+            .canonicalize()
+            .unwrap_or_else(|_| workspace_dir.to_path_buf());
+
+        if !resolved.is_absolute() {
+            anyhow::bail!(
+                "Docker runtime requires an absolute workspace path, got: {}",
+                resolved.display()
+            );
+        }
+
+        if resolved == Path::new("/") {
+            anyhow::bail!("Refusing to mount filesystem root (/) into docker runtime");
+        }
+
+        if self.config.allowed_workspace_roots.is_empty() {
+            return Ok(resolved);
+        }
+
+        let allowed = self.config.allowed_workspace_roots.iter().any(|root| {
+            let root_path = Path::new(root)
+                .canonicalize()
+                .unwrap_or_else(|_| PathBuf::from(root));
+            resolved.starts_with(root_path)
+        });
+
+        if !allowed {
+            anyhow::bail!(
+                "Workspace path {} is not in runtime.docker.allowed_workspace_roots",
+                resolved.display()
+            );
+        }
+
+        Ok(resolved)
+    }
+}
+
+impl RuntimeAdapter for DockerRuntime {
+    fn name(&self) -> &str {
+        "docker"
+    }
+
+    fn has_shell_access(&self) -> bool {
+        true
+    }
+
+    fn has_filesystem_access(&self) -> bool {
+        self.config.mount_workspace
+    }
+
+    fn storage_path(&self) -> PathBuf {
+        if self.config.mount_workspace {
+            PathBuf::from("/workspace/.zeroclaw")
+        } else {
+            PathBuf::from("/tmp/.zeroclaw")
+        }
+    }
+
+    fn supports_long_running(&self) -> bool {
+        false
+    }
+
+    fn memory_budget(&self) -> u64 {
+        self.config
+            .memory_limit_mb
+            .map_or(0, |mb| mb.saturating_mul(1024 * 1024))
+    }
+
+    fn build_shell_command(
+        &self,
+        command: &str,
+        workspace_dir: &Path,
+    ) -> anyhow::Result<tokio::process::Command> {
+        let mut process = tokio::process::Command::new("docker");
+        process
+            .arg("run")
+            .arg("--rm")
+            .arg("--init")
+            .arg("--interactive");
+
+        let network = self.config.network.trim();
+        if !network.is_empty() {
+            process.arg("--network").arg(network);
+        }
+
+        if let Some(memory_limit_mb) = self.config.memory_limit_mb.filter(|mb| *mb > 0) {
+            process.arg("--memory").arg(format!("{memory_limit_mb}m"));
+        }
+
+        if let Some(cpu_limit) = self.config.cpu_limit.filter(|cpus| *cpus > 0.0) {
+            process.arg("--cpus").arg(cpu_limit.to_string());
+        }
+
+        if self.config.read_only_rootfs {
+            process.arg("--read-only");
+        }
+
+        if self.config.mount_workspace {
+            let host_workspace = self.workspace_mount_path(workspace_dir).with_context(|| {
+                format!(
+                    "Failed to validate workspace mount path {}",
+                    workspace_dir.display()
+                )
+            })?;
+
+            process
+                .arg("--volume")
+                .arg(format!("{}:/workspace:rw", host_workspace.display()))
+                .arg("--workdir")
+                .arg("/workspace");
+        }
+
+        process
+            .arg(self.config.image.trim())
+            .arg("sh")
+            .arg("-c")
+            .arg(command);
+
+        Ok(process)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn docker_runtime_name() {
+        let runtime = DockerRuntime::new(DockerRuntimeConfig::default());
+        assert_eq!(runtime.name(), "docker");
+    }
+
+    #[test]
+    fn docker_runtime_memory_budget() {
+        let mut cfg = DockerRuntimeConfig::default();
+        cfg.memory_limit_mb = Some(256);
+        let runtime = DockerRuntime::new(cfg);
+        assert_eq!(runtime.memory_budget(), 256 * 1024 * 1024);
+    }
+
+    #[test]
+    fn docker_build_shell_command_includes_runtime_flags() {
+        let cfg = DockerRuntimeConfig {
+            image: "alpine:3.20".into(),
+            network: "none".into(),
+            memory_limit_mb: Some(128),
+            cpu_limit: Some(1.5),
+            read_only_rootfs: true,
+            mount_workspace: true,
+            allowed_workspace_roots: Vec::new(),
+        };
+        let runtime = DockerRuntime::new(cfg);
+
+        let workspace = std::env::temp_dir();
+        let command = runtime
+            .build_shell_command("echo hello", &workspace)
+            .unwrap();
+        let debug = format!("{command:?}");
+
+        assert!(debug.contains("docker"));
+        assert!(debug.contains("--memory"));
+        assert!(debug.contains("128m"));
+        assert!(debug.contains("--cpus"));
+        assert!(debug.contains("1.5"));
+        assert!(debug.contains("--workdir"));
+        assert!(debug.contains("echo hello"));
+    }
+
+    #[test]
+    fn docker_workspace_allowlist_blocks_outside_paths() {
+        let cfg = DockerRuntimeConfig {
+            allowed_workspace_roots: vec!["/tmp/allowed".into()],
+            ..DockerRuntimeConfig::default()
+        };
+        let runtime = DockerRuntime::new(cfg);
+
+        let outside = PathBuf::from("/tmp/blocked_workspace");
+        let result = runtime.build_shell_command("echo test", &outside);
+
+        assert!(result.is_err());
+    }
+}
diff --git a/src/runtime/mod.rs b/src/runtime/mod.rs
index 9ed0ee0..cea7aa3 100644
--- a/src/runtime/mod.rs
+++ b/src/runtime/mod.rs
@@ -1,6 +1,8 @@
+pub mod docker;
 pub mod native;
 pub mod traits;
 
+pub use docker::DockerRuntime;
 pub use native::NativeRuntime;
 pub use traits::RuntimeAdapter;
 
@@ -10,18 +12,14 @@ use crate::config::RuntimeConfig;
 pub fn create_runtime(config: &RuntimeConfig) -> anyhow::Result<Box<dyn RuntimeAdapter>> {
     match config.kind.as_str() {
         "native" => Ok(Box::new(NativeRuntime::new())),
-        "docker" => anyhow::bail!(
-            "runtime.kind='docker' is not implemented yet. Use runtime.kind='native' until container runtime support lands."
-        ),
+        "docker" => Ok(Box::new(DockerRuntime::new(config.docker.clone()))),
         "cloudflare" => anyhow::bail!(
             "runtime.kind='cloudflare' is not implemented yet. Use runtime.kind='native' for now."
         ),
-        other if other.trim().is_empty() => anyhow::bail!(
-            "runtime.kind cannot be empty. Supported values: native"
-        ),
-        other => anyhow::bail!(
-            "Unknown runtime kind '{other}'. Supported values: native"
-        ),
+        other if other.trim().is_empty() => {
+            anyhow::bail!("runtime.kind cannot be empty. Supported values: native, docker")
+        }
+        other => anyhow::bail!("Unknown runtime kind '{other}'. Supported values: native, docker"),
     }
 }
 
@@ -33,6 +31,7 @@ mod tests {
     fn factory_native() {
         let cfg = RuntimeConfig {
             kind: "native".into(),
+            ..RuntimeConfig::default()
         };
         let rt = create_runtime(&cfg).unwrap();
         assert_eq!(rt.name(), "native");
@@ -40,20 +39,21 @@ mod tests {
     }
 
     #[test]
-    fn factory_docker_errors() {
+    fn factory_docker() {
         let cfg = RuntimeConfig {
             kind: "docker".into(),
+            ..RuntimeConfig::default()
         };
-        match create_runtime(&cfg) {
-            Err(err) => assert!(err.to_string().contains("not implemented")),
-            Ok(_) => panic!("docker runtime should error"),
-        }
+        let rt = create_runtime(&cfg).unwrap();
+        assert_eq!(rt.name(), "docker");
+        assert!(rt.has_shell_access());
     }
 
     #[test]
     fn factory_cloudflare_errors() {
         let cfg = RuntimeConfig {
             kind: "cloudflare".into(),
+            ..RuntimeConfig::default()
         };
         match create_runtime(&cfg) {
             Err(err) => assert!(err.to_string().contains("not implemented")),
@@ -65,6 +65,7 @@ mod tests {
     fn factory_unknown_errors() {
         let cfg = RuntimeConfig {
             kind: "wasm-edge-unknown".into(),
+            ..RuntimeConfig::default()
         };
         match create_runtime(&cfg) {
             Err(err) => assert!(err.to_string().contains("Unknown runtime kind")),
@@ -76,6 +77,7 @@ mod tests {
     fn factory_empty_errors() {
         let cfg = RuntimeConfig {
             kind: String::new(),
+            ..RuntimeConfig::default()
         };
         match create_runtime(&cfg) {
             Err(err) => assert!(err.to_string().contains("cannot be empty")),
diff --git a/src/runtime/native.rs b/src/runtime/native.rs
index 4b0ef3c..927c895 100644
--- a/src/runtime/native.rs
+++ b/src/runtime/native.rs
@@ -1,5 +1,5 @@
 use super::traits::RuntimeAdapter;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
 /// Native runtime — full access, runs on Mac/Linux/Docker/Raspberry Pi
 pub struct NativeRuntime;
@@ -33,6 +33,16 @@ impl RuntimeAdapter for NativeRuntime {
     fn supports_long_running(&self) -> bool {
         true
     }
+
+    fn build_shell_command(
+        &self,
+        command: &str,
+        workspace_dir: &Path,
+    ) -> anyhow::Result<tokio::process::Command> {
+        let mut process = tokio::process::Command::new("sh");
+        process.arg("-c").arg(command).current_dir(workspace_dir);
+        Ok(process)
+    }
 }
 
 #[cfg(test)]
@@ -69,4 +79,14 @@ mod tests {
         let path = NativeRuntime::new().storage_path();
         assert!(path.to_string_lossy().contains("zeroclaw"));
     }
+
+    #[test]
+    fn native_builds_shell_command() {
+        let cwd = std::env::temp_dir();
+        let command = NativeRuntime::new()
+            .build_shell_command("echo hello", &cwd)
+            .unwrap();
+        let debug = format!("{command:?}");
+        assert!(debug.contains("echo hello"));
+    }
 }
diff --git a/src/runtime/traits.rs b/src/runtime/traits.rs
index cbff5b1..743ee5e 100644
--- a/src/runtime/traits.rs
+++ b/src/runtime/traits.rs
@@ -1,4 +1,4 @@
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
 /// Runtime adapter — abstracts platform differences so the same agent
 /// code runs on native, Docker, Cloudflare Workers, Raspberry Pi, etc.
@@ -22,4 +22,11 @@ pub trait RuntimeAdapter: Send + Sync {
     fn memory_budget(&self) -> u64 {
         0
     }
+
+    /// Build a shell command process for this runtime.
+    fn build_shell_command(
+        &self,
+        command: &str,
+        workspace_dir: &Path,
+    ) -> anyhow::Result<tokio::process::Command>;
 }
diff --git a/src/security/policy.rs b/src/security/policy.rs
index 1dd6963..57e8526 100644
--- a/src/security/policy.rs
+++ b/src/security/policy.rs
@@ -16,6 +16,14 @@ pub enum AutonomyLevel {
     Full,
 }
 
+/// Risk score for shell command execution.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum CommandRiskLevel {
+    Low,
+    Medium,
+    High,
+}
+
 /// Sliding-window action tracker for rate limiting.
 #[derive(Debug)]
 pub struct ActionTracker {
@@ -80,6 +88,8 @@ pub struct SecurityPolicy {
     pub forbidden_paths: Vec<String>,
     pub max_actions_per_hour: u32,
     pub max_cost_per_day_cents: u32,
+    pub require_approval_for_medium_risk: bool,
+    pub block_high_risk_commands: bool,
     pub tracker: ActionTracker,
 }
 
@@ -127,6 +137,8 @@ impl Default for SecurityPolicy {
             ],
             max_actions_per_hour: 20,
             max_cost_per_day_cents: 500,
+            require_approval_for_medium_risk: true,
+            block_high_risk_commands: true,
             tracker: ActionTracker::new(),
         }
     }
@@ -156,6 +168,163 @@ fn skip_env_assignments(s: &str) -> &str {
 }
 
 impl SecurityPolicy {
+    /// Classify command risk. Any high-risk segment marks the whole command high.
+    pub fn command_risk_level(&self, command: &str) -> CommandRiskLevel {
+        let mut normalized = command.to_string();
+        for sep in ["&&", "||"] {
+            normalized = normalized.replace(sep, "\x00");
+        }
+        for sep in ['\n', ';', '|'] {
+            normalized = normalized.replace(sep, "\x00");
+        }
+
+        let mut saw_medium = false;
+
+        for segment in normalized.split('\x00') {
+            let segment = segment.trim();
+            if segment.is_empty() {
+                continue;
+            }
+
+            let cmd_part = skip_env_assignments(segment);
+            let mut words = cmd_part.split_whitespace();
+            let Some(base_raw) = words.next() else {
+                continue;
+            };
+
+            let base = base_raw
+                .rsplit('/')
+                .next()
+                .unwrap_or("")
+                .to_ascii_lowercase();
+
+            let args: Vec<String> = words.map(|w| w.to_ascii_lowercase()).collect();
+            let joined_segment = cmd_part.to_ascii_lowercase();
+
+            // High-risk commands
+            if matches!(
+                base.as_str(),
+                "rm" | "mkfs"
+                    | "dd"
+                    | "shutdown"
+                    | "reboot"
+                    | "halt"
+                    | "poweroff"
+                    | "sudo"
+                    | "su"
+                    | "chown"
+                    | "chmod"
+                    | "useradd"
+                    | "userdel"
+                    | "usermod"
+                    | "passwd"
+                    | "mount"
+                    | "umount"
+                    | "iptables"
+                    | "ufw"
+                    | "firewall-cmd"
+                    | "curl"
+                    | "wget"
+                    | "nc"
+                    | "ncat"
+                    | "netcat"
+                    | "scp"
+                    | "ssh"
+                    | "ftp"
+                    | "telnet"
+            ) {
+                return CommandRiskLevel::High;
+            }
+
+            if joined_segment.contains("rm -rf /")
+                || joined_segment.contains("rm -fr /")
+                || joined_segment.contains(":(){:|:&};:")
+            {
+                return CommandRiskLevel::High;
+            }
+
+            // Medium-risk commands (state-changing, but not inherently destructive)
+            let medium = match base.as_str() {
+                "git" => args.first().is_some_and(|verb| {
+                    matches!(
+                        verb.as_str(),
+                        "commit"
+                            | "push"
+                            | "reset"
+                            | "clean"
+                            | "rebase"
+                            | "merge"
+                            | "cherry-pick"
+                            | "revert"
+                            | "branch"
+                            | "checkout"
+                            | "switch"
+                            | "tag"
+                    )
+                }),
+                "npm" | "pnpm" | "yarn" => args.first().is_some_and(|verb| {
+                    matches!(
+                        verb.as_str(),
+                        "install" | "add" | "remove" | "uninstall" | "update" | "publish"
+                    )
+                }),
+                "cargo" => args.first().is_some_and(|verb| {
+                    matches!(
+                        verb.as_str(),
+                        "add" | "remove" | "install" | "clean" | "publish"
+                    )
+                }),
+                "touch" | "mkdir" | "mv" | "cp" | "ln" => true,
+                _ => false,
+            };
+
+            saw_medium |= medium;
+        }
+
+        if saw_medium {
+            CommandRiskLevel::Medium
+        } else {
+            CommandRiskLevel::Low
+        }
+    }
+
+    /// Validate full command execution policy (allowlist + risk gate).
+    pub fn validate_command_execution(
+        &self,
+        command: &str,
+        approved: bool,
+    ) -> Result<CommandRiskLevel, String> {
+        if !self.is_command_allowed(command) {
+            return Err(format!("Command not allowed by security policy: {command}"));
+        }
+
+        let risk = self.command_risk_level(command);
+
+        if risk == CommandRiskLevel::High {
+            if self.block_high_risk_commands {
+                return Err("Command blocked: high-risk command is disallowed by policy".into());
+            }
+            if self.autonomy == AutonomyLevel::Supervised && !approved {
+                return Err(
+                    "Command requires explicit approval (approved=true): high-risk operation"
+                        .into(),
+                );
+            }
+        }
+
+        if risk == CommandRiskLevel::Medium
+            && self.autonomy == AutonomyLevel::Supervised
+            && self.require_approval_for_medium_risk
+            && !approved
+        {
+            return Err(
+                "Command requires explicit approval (approved=true): medium-risk operation".into(),
+            );
+        }
+
+        Ok(risk)
+    }
+
     /// Check if a shell command is allowed.
     ///
     /// Validates the **entire** command string, not just the first word:
@@ -329,6 +498,8 @@ impl SecurityPolicy {
             forbidden_paths: autonomy_config.forbidden_paths.clone(),
             max_actions_per_hour: autonomy_config.max_actions_per_hour,
             max_cost_per_day_cents: autonomy_config.max_cost_per_day_cents,
+            require_approval_for_medium_risk: autonomy_config.require_approval_for_medium_risk,
+            block_high_risk_commands: autonomy_config.block_high_risk_commands,
             tracker: ActionTracker::new(),
         }
     }
@@ -473,6 +644,71 @@ mod tests {
         assert!(!p.is_command_allowed("echo hello"));
     }
 
+    #[test]
+    fn command_risk_low_for_read_commands() {
+        let p = default_policy();
+        assert_eq!(p.command_risk_level("git status"), CommandRiskLevel::Low);
+        assert_eq!(p.command_risk_level("ls -la"), CommandRiskLevel::Low);
+    }
+
+    #[test]
+    fn command_risk_medium_for_mutating_commands() {
+        let p = SecurityPolicy {
+            allowed_commands: vec!["git".into(), "touch".into()],
+            ..SecurityPolicy::default()
+        };
+        assert_eq!(
+            p.command_risk_level("git reset --hard HEAD~1"),
+            CommandRiskLevel::Medium
+        );
+        assert_eq!(
+            p.command_risk_level("touch file.txt"),
+            CommandRiskLevel::Medium
+        );
+    }
+
+    #[test]
+    fn command_risk_high_for_dangerous_commands() {
+        let p = SecurityPolicy {
+            allowed_commands: vec!["rm".into()],
+            ..SecurityPolicy::default()
+        };
+        assert_eq!(
+            p.command_risk_level("rm -rf /tmp/test"),
+            CommandRiskLevel::High
+        );
+    }
+
+    #[test]
+    fn validate_command_requires_approval_for_medium_risk() {
+        let p = SecurityPolicy {
+            autonomy: AutonomyLevel::Supervised,
+            require_approval_for_medium_risk: true,
+            allowed_commands: vec!["touch".into()],
+            ..SecurityPolicy::default()
+        };
+
+        let denied = p.validate_command_execution("touch test.txt", false);
+        assert!(denied.is_err());
+        assert!(denied.unwrap_err().contains("requires explicit approval"),);
+
+        let allowed = p.validate_command_execution("touch test.txt", true);
+        assert_eq!(allowed.unwrap(), CommandRiskLevel::Medium);
+    }
+
+    #[test]
+    fn validate_command_blocks_high_risk_by_default() {
+        let p = SecurityPolicy {
+            autonomy: AutonomyLevel::Supervised,
+            allowed_commands: vec!["rm".into()],
+            ..SecurityPolicy::default()
+        };
+
+        let result = p.validate_command_execution("rm -rf /tmp/test", true);
+        assert!(result.is_err());
+        assert!(result.unwrap_err().contains("high-risk"));
+    }
+
     // ── is_path_allowed ─────────────────────────────────────
 
     #[test]
@@ -546,6 +782,8 @@ mod tests {
             forbidden_paths: vec!["/secret".into()],
             max_actions_per_hour: 100,
             max_cost_per_day_cents: 1000,
+            require_approval_for_medium_risk: false,
+            block_high_risk_commands: false,
         };
         let workspace = PathBuf::from("/tmp/test-workspace");
         let policy = SecurityPolicy::from_config(&autonomy_config, &workspace);
@@ -556,6 +794,8 @@ mod tests {
         assert_eq!(policy.forbidden_paths, vec!["/secret"]);
         assert_eq!(policy.max_actions_per_hour, 100);
         assert_eq!(policy.max_cost_per_day_cents, 1000);
+        assert!(!policy.require_approval_for_medium_risk);
+        assert!(!policy.block_high_risk_commands);
         assert_eq!(policy.workspace_dir, PathBuf::from("/tmp/test-workspace"));
     }
 
@@ -570,6 +810,8 @@ mod tests {
         assert!(!p.forbidden_paths.is_empty());
         assert!(p.max_actions_per_hour > 0);
         assert!(p.max_cost_per_day_cents > 0);
+        assert!(p.require_approval_for_medium_risk);
+        assert!(p.block_high_risk_commands);
     }
 
     // ── ActionTracker / rate limiting ───────────────────────
@@ -853,6 +1095,8 @@ mod tests {
             forbidden_paths: vec![],
             max_actions_per_hour: 10,
             max_cost_per_day_cents: 100,
+            require_approval_for_medium_risk: true,
+            block_high_risk_commands: true,
         };
         let workspace = PathBuf::from("/tmp/test");
         let policy = SecurityPolicy::from_config(&autonomy_config, &workspace);
diff --git a/src/tools/mod.rs b/src/tools/mod.rs
index e02154d..6f9891f 100644
--- a/src/tools/mod.rs
+++ b/src/tools/mod.rs
@@ -23,13 +23,22 @@ pub use traits::Tool;
 pub use traits::{ToolResult, ToolSpec};
 
 use crate::memory::Memory;
+use crate::runtime::{NativeRuntime, RuntimeAdapter};
 use crate::security::SecurityPolicy;
 use std::sync::Arc;
 
 /// Create the default tool registry
 pub fn default_tools(security: Arc<SecurityPolicy>) -> Vec<Box<dyn Tool>> {
+    default_tools_with_runtime(security, Arc::new(NativeRuntime::new()))
+}
+
+/// Create the default tool registry with explicit runtime adapter.
+pub fn default_tools_with_runtime(
+    security: Arc<SecurityPolicy>,
+    runtime: Arc<dyn RuntimeAdapter>,
+) -> Vec<Box<dyn Tool>> {
     vec![
-        Box::new(ShellTool::new(security.clone())),
+        Box::new(ShellTool::new(security.clone(), runtime)),
         Box::new(FileReadTool::new(security.clone())),
         Box::new(FileWriteTool::new(security)),
     ]
@@ -41,9 +50,26 @@ pub fn all_tools(
     memory: Arc<dyn Memory>,
     composio_key: Option<&str>,
     browser_config: &crate::config::BrowserConfig,
+) -> Vec<Box<dyn Tool>> {
+    all_tools_with_runtime(
+        security,
+        Arc::new(NativeRuntime::new()),
+        memory,
+        composio_key,
+        browser_config,
+    )
+}
+
+/// Create full tool registry including memory tools and optional Composio.
+pub fn all_tools_with_runtime(
+    security: &Arc<SecurityPolicy>,
+    runtime: Arc<dyn RuntimeAdapter>,
+    memory: Arc<dyn Memory>,
+    composio_key: Option<&str>,
+    browser_config: &crate::config::BrowserConfig,
 ) -> Vec<Box<dyn Tool>> {
     let mut tools: Vec<Box<dyn Tool>> = vec![
-        Box::new(ShellTool::new(security.clone())),
+        Box::new(ShellTool::new(security.clone(), runtime)),
         Box::new(FileReadTool::new(security.clone())),
         Box::new(FileWriteTool::new(security.clone())),
         Box::new(MemoryStoreTool::new(memory.clone())),
diff --git a/src/tools/shell.rs b/src/tools/shell.rs
index a06558b..662d7ab 100644
--- a/src/tools/shell.rs
+++ b/src/tools/shell.rs
@@ -1,4 +1,5 @@
 use super::traits::{Tool, ToolResult};
+use crate::runtime::RuntimeAdapter;
 use crate::security::SecurityPolicy;
 use async_trait::async_trait;
 use serde_json::json;
@@ -18,11 +19,12 @@ const SAFE_ENV_VARS: &[&str] = &[
 /// Shell command execution tool with sandboxing
 pub struct ShellTool {
     security: Arc<SecurityPolicy>,
+    runtime: Arc<dyn RuntimeAdapter>,
 }
 
 impl ShellTool {
-    pub fn new(security: Arc<SecurityPolicy>) -> Self {
-        Self { security }
+    pub fn new(security: Arc<SecurityPolicy>, runtime: Arc<dyn RuntimeAdapter>) -> Self {
+        Self { security, runtime }
     }
 }
 
@@ -43,6 +45,11 @@ impl Tool for ShellTool {
                 "command": {
                     "type": "string",
                     "description": "The shell command to execute"
+                },
+                "approved": {
+                    "type": "boolean",
+                    "description": "Set true to explicitly approve medium/high-risk commands in supervised mode",
+                    "default": false
                 }
             },
             "required": ["command"]
@@ -54,24 +61,55 @@ impl Tool for ShellTool {
             .get("command")
             .and_then(|v| v.as_str())
             .ok_or_else(|| anyhow::anyhow!("Missing 'command' parameter"))?;
+        let approved = args
+            .get("approved")
+            .and_then(|v| v.as_bool())
+            .unwrap_or(false);
 
-        // Security check: validate command against allowlist
-        if !self.security.is_command_allowed(command) {
+        if self.security.is_rate_limited() {
             return Ok(ToolResult {
                 success: false,
                 output: String::new(),
-                error: Some(format!("Command not allowed by security policy: {command}")),
+                error: Some("Rate limit exceeded: too many actions in the last hour".into()),
+            });
+        }
+
+        match self.security.validate_command_execution(command, approved) {
+            Ok(_) => {}
+            Err(reason) => {
+                return Ok(ToolResult {
+                    success: false,
+                    output: String::new(),
+                    error: Some(reason),
+                });
+            }
+        }
+
+        if !self.security.record_action() {
+            return Ok(ToolResult {
+                success: false,
+                output: String::new(),
+                error: Some("Rate limit exceeded: action budget exhausted".into()),
             });
         }
 
         // Execute with timeout to prevent hanging commands.
         // Clear the environment to prevent leaking API keys and other secrets
         // (CWE-200), then re-add only safe, functional variables.
-        let mut cmd = tokio::process::Command::new("sh");
-        cmd.arg("-c")
-            .arg(command)
-            .current_dir(&self.security.workspace_dir)
-            .env_clear();
+        let mut cmd = match self
+            .runtime
+            .build_shell_command(command, &self.security.workspace_dir)
+        {
+            Ok(cmd) => cmd,
+            Err(e) => {
+                return Ok(ToolResult {
+                    success: false,
+                    output: String::new(),
+                    error: Some(format!("Failed to build runtime command: {e}")),
+                });
+            }
+        };
+        cmd.env_clear();
 
         for var in SAFE_ENV_VARS {
             if let Ok(val) = std::env::var(var) {
@@ -126,6 +164,7 @@ impl Tool for ShellTool {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::runtime::{NativeRuntime, RuntimeAdapter};
     use crate::security::{AutonomyLevel, SecurityPolicy};
 
     fn test_security(autonomy: AutonomyLevel) -> Arc<SecurityPolicy> {
@@ -136,32 +175,37 @@ mod tests {
         })
     }
 
+    fn test_runtime() -> Arc<dyn RuntimeAdapter> {
+        Arc::new(NativeRuntime::new())
+    }
+
     #[test]
     fn shell_tool_name() {
-        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised));
+        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised), test_runtime());
         assert_eq!(tool.name(), "shell");
     }
 
     #[test]
     fn shell_tool_description() {
-        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised));
+        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised), test_runtime());
         assert!(!tool.description().is_empty());
     }
 
     #[test]
     fn shell_tool_schema_has_command() {
-        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised));
+        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised), test_runtime());
         let schema = tool.parameters_schema();
         assert!(schema["properties"]["command"].is_object());
         assert!(schema["required"]
             .as_array()
             .unwrap()
             .contains(&json!("command")));
+        assert!(schema["properties"]["approved"].is_object());
     }
 
     #[tokio::test]
     async fn shell_executes_allowed_command() {
-        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised));
+        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised), test_runtime());
         let result = tool
             .execute(json!({"command": "echo hello"}))
             .await
@@ -173,15 +217,16 @@ mod tests {
 
     #[tokio::test]
     async fn shell_blocks_disallowed_command() {
-        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised));
+        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised), test_runtime());
         let result = tool.execute(json!({"command": "rm -rf /"})).await.unwrap();
         assert!(!result.success);
-        assert!(result.error.as_ref().unwrap().contains("not allowed"));
+        let error = result.error.as_deref().unwrap_or("");
+        assert!(error.contains("not allowed") || error.contains("high-risk"));
     }
 
     #[tokio::test]
     async fn shell_blocks_readonly() {
-        let tool = ShellTool::new(test_security(AutonomyLevel::ReadOnly));
+        let tool = ShellTool::new(test_security(AutonomyLevel::ReadOnly), test_runtime());
         let result = tool.execute(json!({"command": "ls"})).await.unwrap();
         assert!(!result.success);
         assert!(result.error.as_ref().unwrap().contains("not allowed"));
@@ -189,7 +234,7 @@ mod tests {
 
     #[tokio::test]
     async fn shell_missing_command_param() {
-        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised));
+        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised), test_runtime());
         let result = tool.execute(json!({})).await;
         assert!(result.is_err());
         assert!(result.unwrap_err().to_string().contains("command"));
@@ -197,14 +242,14 @@ mod tests {
 
     #[tokio::test]
     async fn shell_wrong_type_param() {
-        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised));
+        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised), test_runtime());
         let result = tool.execute(json!({"command": 123})).await;
         assert!(result.is_err());
     }
 
     #[tokio::test]
     async fn shell_captures_exit_code() {
-        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised));
+        let tool = ShellTool::new(test_security(AutonomyLevel::Supervised), test_runtime());
         let result = tool
             .execute(json!({"command": "ls /nonexistent_dir_xyz"}))
             .await
@@ -250,7 +295,7 @@ mod tests {
         let _g1 = EnvGuard::set("API_KEY", "sk-test-secret-12345");
         let _g2 = EnvGuard::set("ZEROCLAW_API_KEY", "sk-test-secret-67890");
 
-        let tool = ShellTool::new(test_security_with_env_cmd());
+        let tool = ShellTool::new(test_security_with_env_cmd(), test_runtime());
         let result = tool.execute(json!({"command": "env"})).await.unwrap();
         assert!(result.success);
         assert!(
@@ -265,7 +310,7 @@ mod tests {
 
     #[tokio::test]
     async fn shell_preserves_path_and_home() {
-        let tool = ShellTool::new(test_security_with_env_cmd());
+        let tool = ShellTool::new(test_security_with_env_cmd(), test_runtime());
 
         let result = tool
             .execute(json!({"command": "echo $HOME"}))
@@ -287,4 +332,37 @@ mod tests {
             "PATH should be available in shell"
         );
     }
+
+    #[tokio::test]
+    async fn shell_requires_approval_for_medium_risk_command() {
+        let security = Arc::new(SecurityPolicy {
+            autonomy: AutonomyLevel::Supervised,
+            allowed_commands: vec!["touch".into()],
+            workspace_dir: std::env::temp_dir(),
+            ..SecurityPolicy::default()
+        });
+
+        let tool = ShellTool::new(security.clone(), test_runtime());
+        let denied = tool
+            .execute(json!({"command": "touch zeroclaw_shell_approval_test"}))
+            .await
+            .unwrap();
+        assert!(!denied.success);
+        assert!(denied
+            .error
+            .as_deref()
+            .unwrap_or("")
+            .contains("explicit approval"));
+
+        let allowed = tool
+            .execute(json!({
+                "command": "touch zeroclaw_shell_approval_test",
+                "approved": true
+            }))
+            .await
+            .unwrap();
+        assert!(allowed.success);
+
+        let _ = std::fs::remove_file(std::env::temp_dir().join("zeroclaw_shell_approval_test"));
+    }
 }