feat: LSP (Language Server Protocol) integration v3 — clean rebuild

rust/crates/commands/src/lib.rs

@@ -796,6 +796,13 @@ const SLASH_COMMAND_SPECS: &[SlashCommandSpec] = &[
         argument_hint: Some("[list|add|remove]"),
         resume_supported: true,
     },
+    SlashCommandSpec {
+        name: "lsp",
+        aliases: &[],
+        summary: "Show or manage LSP server status",
+        argument_hint: Some("[status|start|stop|list]"),
+        resume_supported: true,
+    },
     SlashCommandSpec {
         name: "team",
         aliases: &[],
@@ -1180,6 +1187,10 @@ pub enum SlashCommand {
         count: Option<String>,
     },
     Unknown(String),
+    Lsp {
+        action: Option<String>,
+        target: Option<String>,
+    },
     Team {
         action: Option<String>,
     },
@@ -1280,6 +1291,7 @@ impl SlashCommand {
             Self::Tag { .. } => "/tag",
             Self::OutputStyle { .. } => "/output-style",
             Self::AddDir { .. } => "/add-dir",
+            Self::Lsp { .. } => "/lsp",
             Self::Team { .. } => "/team",
             Self::Sandbox => "/sandbox",
             Self::Mcp { .. } => "/mcp",
@@ -1495,6 +1507,10 @@ pub fn validate_slash_command_input(
         "history" => SlashCommand::History {
             count: optional_single_arg(command, &args, "[count]")?,
         },
+        "lsp" => SlashCommand::Lsp {
+            action: args.first().map(|s| (*s).to_string()),
+            target: args.get(1).map(|s| (*s).to_string()),
+        },
         other => SlashCommand::Unknown(other.to_string()),
     }))
 }
@@ -4623,6 +4639,7 @@ pub fn handle_slash_command(
         | SlashCommand::OutputStyle { .. }
         | SlashCommand::AddDir { .. }
         | SlashCommand::History { .. }
+        | SlashCommand::Lsp { .. }
         | SlashCommand::Team { .. }
         | SlashCommand::Unknown(_) => None,
     }

rust/crates/runtime/src/config.rs

@@ -81,8 +81,16 @@ pub struct RuntimePluginConfig {
     max_output_tokens: Option<u32>,
 }
 
+/// Per-language LSP server configuration supplied by the user in settings.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct LspServerConfig {
+    pub command: String,
+    pub args: Vec<String>,
+    pub enabled: bool,
+}
+
 /// Structured feature configuration consumed by runtime subsystems.
-#[derive(Debug, Clone, PartialEq, Eq, Default)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct RuntimeFeatureConfig {
     hooks: RuntimeHookConfig,
     plugins: RuntimePluginConfig,
@@ -95,6 +103,28 @@ pub struct RuntimeFeatureConfig {
     sandbox: SandboxConfig,
     provider_fallbacks: ProviderFallbackConfig,
     trusted_roots: Vec<String>,
+    lsp_auto_start: bool,
+    lsp: BTreeMap<String, LspServerConfig>,
+}
+
+impl Default for RuntimeFeatureConfig {
+    fn default() -> Self {
+        Self {
+            hooks: RuntimeHookConfig::default(),
+            plugins: RuntimePluginConfig::default(),
+            mcp: McpConfigCollection::default(),
+            oauth: None,
+            model: None,
+            aliases: BTreeMap::new(),
+            permission_mode: None,
+            permission_rules: RuntimePermissionRuleConfig::default(),
+            sandbox: SandboxConfig::default(),
+            provider_fallbacks: ProviderFallbackConfig::default(),
+            trusted_roots: Vec::new(),
+            lsp_auto_start: true,
+            lsp: BTreeMap::new(),
+        }
+    }
 }
 
 /// Ordered chain of fallback model identifiers used when the primary
@@ -353,6 +383,12 @@ impl ConfigLoader {
             sandbox: parse_optional_sandbox_config(&merged_value)?,
             provider_fallbacks: parse_optional_provider_fallbacks(&merged_value)?,
             trusted_roots: parse_optional_trusted_roots(&merged_value)?,
+            lsp_auto_start: merged_value
+                .as_object()
+                .and_then(|o| o.get("lspAutoStart"))
+                .and_then(|v| v.as_bool())
+                .unwrap_or(true),
+            lsp: parse_optional_lsp_config(&merged_value)?,
         };
 
         Ok(RuntimeConfig {
@@ -410,6 +446,12 @@ impl ConfigLoader {
             sandbox: parse_optional_sandbox_config(&merged_value)?,
             provider_fallbacks: parse_optional_provider_fallbacks(&merged_value)?,
             trusted_roots: parse_optional_trusted_roots(&merged_value)?,
+            lsp_auto_start: merged_value
+                .as_object()
+                .and_then(|o| o.get("lspAutoStart"))
+                .and_then(|v| v.as_bool())
+                .unwrap_or(true),
+            lsp: parse_optional_lsp_config(&merged_value)?,
         };
 
         let config = RuntimeConfig {
@@ -596,6 +638,16 @@ impl RuntimeFeatureConfig {
     pub fn trusted_roots_with_overrides(&self, per_call_roots: &[String]) -> Vec<String> {
         merge_trusted_roots(self.trusted_roots(), per_call_roots)
     }
+
+    #[must_use]
+    pub fn lsp(&self) -> &BTreeMap<String, LspServerConfig> {
+        &self.lsp
+    }
+
+    #[must_use]
+    pub fn lsp_auto_start(&self) -> bool {
+        self.lsp_auto_start
+    }
 }
 
 fn merge_trusted_roots(config_roots: &[String], per_call_roots: &[String]) -> Vec<String> {
@@ -1162,6 +1214,35 @@ fn parse_optional_trusted_roots(root: &JsonValue) -> Result<Vec<String>, ConfigE
     )
 }
 
+fn parse_optional_lsp_config(
+    root: &JsonValue,
+) -> Result<BTreeMap<String, LspServerConfig>, ConfigError> {
+    let Some(lsp_value) = root.as_object().and_then(|object| object.get("lsp")) else {
+        return Ok(BTreeMap::new());
+    };
+    let lsp_object = expect_object(lsp_value, "merged settings.lsp")?;
+    let mut result = BTreeMap::new();
+    for (language, value) in lsp_object {
+        let entry = expect_object(value, &format!("merged settings.lsp.{language}"))?;
+        let command =
+            expect_string(entry, "command", &format!("merged settings.lsp.{language}"))?.to_owned();
+        let args =
+            optional_string_array(entry, "args", &format!("merged settings.lsp.{language}"))?
+                .unwrap_or_default();
+        let enabled = optional_bool(entry, "enabled", &format!("merged settings.lsp.{language}"))?
+            .unwrap_or(true);
+        result.insert(
+            language.clone(),
+            LspServerConfig {
+                command,
+                args,
+                enabled,
+            },
+        );
+    }
+    Ok(result)
+}
+
 fn parse_filesystem_mode_label(value: &str) -> Result<FilesystemIsolationMode, ConfigError> {
     match value {
         "off" => Ok(FilesystemIsolationMode::Off),

rust/crates/runtime/src/lib.rs

@@ -21,6 +21,9 @@ mod hooks;
 mod json;
 mod lane_events;
 pub mod lsp_client;
+pub mod lsp_discovery;
+pub mod lsp_process;
+pub mod lsp_transport;
 mod mcp;
 mod mcp_client;
 pub mod mcp_lifecycle_hardened;
@@ -66,8 +69,8 @@ pub use compact::{
 };
 pub use config::{
     suppress_config_warnings_for_json_mode, ConfigEntry, ConfigError, ConfigLoader, ConfigSource,
-    McpConfigCollection, McpManagedProxyServerConfig, McpOAuthConfig, McpRemoteServerConfig,
-    McpSdkServerConfig, McpServerConfig, McpStdioServerConfig, McpTransport,
+    LspServerConfig, McpConfigCollection, McpManagedProxyServerConfig, McpOAuthConfig,
+    McpRemoteServerConfig, McpSdkServerConfig, McpServerConfig, McpStdioServerConfig, McpTransport,
     McpWebSocketServerConfig, OAuthConfig, ProviderFallbackConfig, ResolvedPermissionMode,
     RuntimeConfig, RuntimeFeatureConfig, RuntimeHookConfig, RuntimePermissionRuleConfig,
     RuntimePluginConfig, ScopedMcpServerConfig, CLAW_SETTINGS_SCHEMA_NAME,
@@ -98,6 +101,10 @@ pub use lane_events::{
     LaneFailureClass, LaneOwnership, SessionIdentity, ShipMergeMethod, ShipProvenance,
     WatcherAction,
 };
+pub use lsp_discovery::{
+    command_exists_on_path, discover_available_servers, find_server_for_file, known_lsp_servers,
+    LspServerDescriptor,
+};
 pub use mcp::{
     mcp_server_signature, mcp_tool_name, mcp_tool_prefix, normalize_name_for_mcp,
     scoped_mcp_config_hash, unwrap_ccr_proxy_url,