remove agent-callable restart tool (blast radius in multi-user model)

crates/skald-core/src/approval/mod.rs

@@ -231,7 +231,6 @@ impl ApprovalManager {
 
         let defaults: &[(&str, &str)] = &[
             (tn::EXECUTE_CMD, "require"),
-            (tn::RESTART,     "require"),
             // Opening a mobile pairing window emits a secret (the QR) into chat:
             // it must be a deliberate human action, not LLM-triggerable (plugin.md §11).
             ("mobile_start_pairing", "require"),

crates/skald-core/src/session/handler/approval.rs

@@ -41,13 +41,6 @@ impl ChatSessionHandler {
         } else if tool_name == tn::EXECUTE_CMD {
             let cmd = arguments["command"].as_str().unwrap_or("");
             em.pending_write(request_id, tool_call_id, "$ execute_cmd".to_string(), None, format!("$ {cmd}")).await;
-        } else if tool_name == tn::RESTART {
-            em.pending_write(
-                request_id, tool_call_id,
-                "$ restart".to_string(),
-                None,
-                "Riavvia il processo (exit -1 → supervisor ricompila e rilancia)".to_string(),
-            ).await;
         } else {
             em.approval_required(request_id, tool_call_id, tool_name.to_string(), arguments.clone()).await;
         }

crates/skald-core/src/session/handler/llm_loop.rs

@@ -1,9 +1,8 @@
 use std::sync::Arc;
 use tokio::sync::mpsc;
 use tokio_util::sync::CancellationToken;
-use tracing::{debug, info, trace};
+use tracing::{debug, trace};
 
-use crate::tools::tool_names as tn;
 use crate::chat_event_bus::ToolCallEvent;
 use crate::chatbot::{LlmTurn, ToolCall};
 use crate::db::{chat_history, chat_llm_tools};
@@ -264,18 +263,6 @@ impl ChatSessionHandler {
 
         debug!(session_id = self.session_id, tool = %call.name, tool_call_id, "dispatching");
 
-        // `restart` calls process::exit — mark the call done in the DB first so it
-        // doesn't reappear as `pending` after the supervisor relaunches.
-        if call.name == tn::RESTART {
-            info!(session_id = self.session_id, tool_call_id, "restart approved — marking done then exiting");
-            chat_llm_tools::complete(pool, tool_call_id, "Riavvio avviato.", "string").await?;
-            em.tool_done(tool_call_id, "Riavvio avviato.".to_string(), "string".to_string(), None, None).await;
-            // Use _exit() to skip C atexit handlers (e.g. Metal GPU cleanup in
-            // whisper-rs/ggml, which aborts with SIGABRT and yields exit code 134
-            // instead of 255 — breaking the run.sh restart supervisor).
-            unsafe { libc::_exit(-1) }
-        }
-
         // Route the approved call to its executor. `AbortPending` means the
         // clarification WS channel closed — end the turn and leave the tool
         // `pending` for resume to re-ask.

crates/skald-core/src/session/handler/resume.rs

@@ -358,17 +358,6 @@ impl ChatSessionHandler {
                 GateOutcome::ChannelClosed => return Ok(true), // pending still, WS disconnected
             }
 
-            // `restart` calls process::exit and never returns — mark done first.
-            if tc.name == tn::RESTART {
-                info!(session_id = self.session_id, tool_call_id = tc.id, "restart approved (resume) — marking done then exiting");
-                chat_llm_tools::complete(pool, tc.id, "Riavvio avviato.", "string").await?;
-                em.tool_done(tc.id, "Riavvio avviato.".to_string(), "string".to_string(), None, None).await;
-                // Use _exit() to skip C atexit handlers (e.g. Metal GPU cleanup in
-                // whisper-rs/ggml, which aborts with SIGABRT and yields exit code 134
-                // instead of 255 — breaking the run.sh restart supervisor).
-                unsafe { libc::_exit(-1) }
-            }
-
             // Re-run the persisted intent through the SAME dispatcher as a live turn
             // (`execute_tool_call`), not the flat `build_execution`. This routes
             // sub-agent tools (`execute_task` mode=sync, `execute_subtask`,

crates/skald-core/src/skald/bundles.rs

@@ -211,7 +211,6 @@ impl Tools {
         tool_registry.register(crate::tools::ast_outline::AstOutline::new());
         tool_registry.register(crate::tools::exec::ExecuteCmd);
         tool_registry.register(crate::tools::read_notification::ReadNotification);
-        tool_registry.register(crate::tools::restart::Restart);
         // Unified listing / toggling across plugins, cron (+ agents for list). MCP
         // is no longer agent-managed (blueprint §14): connectors are curated by the
         // admin and activated by the user via the Connectors UI/API, not tools.

crates/skald-core/src/tools/mod.rs

@@ -43,7 +43,6 @@ pub mod list_secrets;
 pub mod notify;
 pub mod set_secret;
 pub mod read_notification;
-pub mod restart;
 pub mod show_file;
 pub mod toggle_item;
 

crates/skald-core/src/tools/restart.rs

@@ -1,69 +0,0 @@
-use std::sync::OnceLock;
-
-use anyhow::Result;
-use serde_json::{Value, json};
-use tracing::{info, warn};
-
-use crate::tools::{Tool, ToolDescriptionLength};
-
-/// How to restart, when exiting for a supervisor is not the answer.
-///
-/// A shell with no supervisor watching its exit code would need to tear itself
-/// down and respawn on its own. That is knowledge about the process shell, which
-/// the core does not have — so such a shell installs it here. The default server
-/// shell has a supervisor (`run.sh`) and installs no handler, so `restart` falls
-/// back to the supervisor protocol below.
-///
-/// Returns only on failure; a successful handler never comes back.
-pub type RestartHandler = Box<dyn Fn() -> Result<()> + Send + Sync>;
-
-static HANDLER: OnceLock<RestartHandler> = OnceLock::new();
-
-/// Called once by the process shell during startup, before any tool can run.
-pub fn set_restart_handler(handler: RestartHandler) {
-    if HANDLER.set(handler).is_err() {
-        warn!("a restart handler is already installed — ignoring this one");
-    }
-}
-
-pub struct Restart;
-
-impl Tool for Restart {
-    fn name(&self) -> &str { crate::tools::tool_names::RESTART }
-    fn category(&self) -> crate::tools::ToolCategory { crate::tools::ToolCategory::Shell }
-
-    fn description(&self) -> &str {
-        "Restart the skald process. Nothing is recompiled: the same binary is re-executed, \
-         so this applies config.yml and database changes, which are only read at startup. \
-         To load new code, build first (./build.sh), then restart. \
-         Requires user approval."
-    }
-
-    fn parameters_schema(&self) -> Value {
-        json!({
-            "type": "object",
-            "properties": {}
-        })
-    }
-
-    fn describe(&self, _args: &Value, _length: ToolDescriptionLength) -> String {
-        "restart skald".to_string()
-    }
-
-    fn execute(&self, _args: Value) -> Result<String> {
-        // A shell that installed its own teardown-and-respawn handles it here.
-        // Normally this never returns.
-        if let Some(handler) = HANDLER.get() {
-            info!("restart requested — delegating to the installed handler");
-            handler()?;
-            warn!("the restart handler returned without restarting — falling back");
-        }
-
-        // Headless: exit with code -1 (= 255 on Unix), which `run.sh` reads as
-        // "re-execute me". `_exit()` rather than `exit()` skips C atexit handlers
-        // — whisper-rs's Metal GPU cleanup aborts with SIGABRT, turning the exit
-        // code into 134 and stopping the supervisor instead of restarting it.
-        info!("restart requested — exit(-1) → supervisor re-executes the binary");
-        unsafe { libc::_exit(-1) }
-    }
-}

crates/skald-core/src/tools/tool_names.rs

@@ -1,6 +1,5 @@
 pub const EXECUTE_TASK:           &str = "execute_task";
 pub const EXECUTE_SUBTASK:        &str = "execute_subtask";
-pub const RESTART:                &str = "restart";
 pub const UPDATE_SCRATCHPAD:      &str = "update_scratchpad";
 pub const WRITE_TODOS:            &str = "write_todos";
 pub const ASK_USER_CLARIFICATION: &str = "ask_user_clarification";