feat(settings): add Web Tools tab with v0.13 search/extract split

Adds a new "Web Tools" Settings tab (between Browser and Voice) with
two distinct shapes that share the same chrome:

- Pre-v0.13: a single "Backend" picker writing the legacy
  `web_tools.backend` key (so v0.12 users still configure web tools).
- v0.13+: two pickers — Search backend writes
  `web_tools.search.backend` (SearXNG appears here only — Hermes
  registers it as a search-only dispatch), Extract backend writes
  `web_tools.extract.backend`.

Capability gate: `hasWebToolsBackendSplit` chooses which shape
renders. The tab itself is always visible — pre-v0.13 users would
otherwise lose access to the legacy combined-backend picker.

Model layer:
- `HermesConfig.webToolsBackend` / `webToolsSearchBackend` /
  `webToolsExtractBackend` — three fields, each round-tripping its
  own YAML key. Defaults: `duckduckgo` / `duckduckgo` / `reader`.
- YAML parser reads all three keys via the existing `str(...)`
  helper. Pre-v0.13 hosts populate only `webToolsBackend`; the
  split keys default to the same backend so the picker shows the
  same value the user already had.

TODO markers (WS-7-Q6/Q7) flag the inline backend lists + legacy
fallback semantics — verify against `~/.hermes/hermes-agent/
hermes_cli/web_tools.py` during integration.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scarf/Packages/ScarfCore/Sources/ScarfCore/Models/HermesConfig.swift

@@ -666,6 +666,18 @@ public struct HermesConfig: Sendable {
     /// final reply (provider/model/cost/turn count). Off by default;
     /// useful for cost auditing and screen-recording demos.
     public var runtimeMetadataFooter: Bool
+    /// Pre-v0.13: single combined Web Tools backend at `web_tools.backend`.
+    /// v0.13 split this into per-capability keys (see below). Kept readable
+    /// for round-trip compatibility on hosts that never migrated; v0.13+
+    /// hosts ignore this scalar and read the split keys instead.
+    public var webToolsBackend: String
+    /// v0.13+: `web_tools.search.backend`. SearXNG is search-only and
+    /// can land here. Pre-v0.13 hosts default to the same value as the
+    /// combined backend.
+    public var webToolsSearchBackend: String
+    /// v0.13+: `web_tools.extract.backend`. Pre-v0.13 hosts default to
+    /// the same value as the combined backend.
+    public var webToolsExtractBackend: String
 
     // Grouped blocks
     public var display: DisplaySettings
@@ -747,11 +759,17 @@ public struct HermesConfig: Sendable {
         homeAssistant: HomeAssistantSettings,
         cacheTTL: String = "5m",
         redactionEnabled: Bool = false,
-        runtimeMetadataFooter: Bool = false
+        runtimeMetadataFooter: Bool = false,
+        webToolsBackend: String = "duckduckgo",
+        webToolsSearchBackend: String = "duckduckgo",
+        webToolsExtractBackend: String = "reader"
     ) {
         self.cacheTTL = cacheTTL
         self.redactionEnabled = redactionEnabled
         self.runtimeMetadataFooter = runtimeMetadataFooter
+        self.webToolsBackend = webToolsBackend
+        self.webToolsSearchBackend = webToolsSearchBackend
+        self.webToolsExtractBackend = webToolsExtractBackend
         self.model = model
         self.provider = provider
         self.maxTurns = maxTurns

scarf/Packages/ScarfCore/Sources/ScarfCore/Parsing/HermesConfig+YAML.swift

@@ -284,7 +284,14 @@ public extension HermesConfig {
             homeAssistant: homeAssistant,
             cacheTTL: str("prompt_caching.cache_ttl", default: "5m"),
             redactionEnabled: bool("redaction.enabled", default: false),
-            runtimeMetadataFooter: bool("agent.runtime_metadata_footer", default: false)
+            runtimeMetadataFooter: bool("agent.runtime_metadata_footer", default: false),
+            // Pre-v0.13 hosts wrote a single `web_tools.backend`. v0.13 split
+            // it into per-capability keys. Read all three so the round-trip
+            // never loses a value the user already set; the WebTools tab
+            // chooses which to render based on `hasWebToolsBackendSplit`.
+            webToolsBackend: str("web_tools.backend", default: "duckduckgo"),
+            webToolsSearchBackend: str("web_tools.search.backend", default: "duckduckgo"),
+            webToolsExtractBackend: str("web_tools.extract.backend", default: "reader")
         )
     }
 }

scarf/scarf/Features/Settings/ViewModels/SettingsViewModel.swift

@@ -143,6 +143,16 @@ final class SettingsViewModel {
     func setBrowserAllowPrivateURLs(_ value: Bool) { setSetting("browser.allow_private_urls", value: value ? "true" : "false") }
     func setCamofoxManagedPersistence(_ value: Bool) { setSetting("browser.camofox.managed_persistence", value: value ? "true" : "false") }
 
+    // MARK: - Web Tools
+
+    /// Pre-v0.13 combined backend. Pre-v0.13 hosts read this; v0.13+
+    /// hosts read it for back-compat but the WebToolsTab gates writes
+    /// on `hasWebToolsBackendSplit` so the tab only writes the split
+    /// keys on v0.13.
+    func setWebToolsBackend(_ value: String) { setSetting("web_tools.backend", value: value) }
+    func setWebToolsSearchBackend(_ value: String) { setSetting("web_tools.search.backend", value: value) }
+    func setWebToolsExtractBackend(_ value: String) { setSetting("web_tools.extract.backend", value: value) }
+
     // MARK: - Voice / TTS / STT
 
     func setAutoTTS(_ value: Bool) { setSetting("voice.auto_tts", value: value ? "true" : "false") }

scarf/scarf/Features/Settings/Views/SettingsView.swift

@@ -26,6 +26,7 @@ struct SettingsView: View {
         case agent = "Agent"
         case terminal = "Terminal"
         case browser = "Browser"
+        case webTools = "Web Tools"
         case voice = "Voice"
         case memory = "Memory"
         case auxiliary = "Aux Models"
@@ -41,6 +42,7 @@ struct SettingsView: View {
             case .agent: return "Agent"
             case .terminal: return "Terminal"
             case .browser: return "Browser"
+            case .webTools: return "Web Tools"
             case .voice: return "Voice"
             case .memory: return "Memory"
             case .auxiliary: return "Aux Models"
@@ -56,6 +58,7 @@ struct SettingsView: View {
             case .agent: return "brain.head.profile"
             case .terminal: return "terminal"
             case .browser: return "globe"
+            case .webTools: return "globe.americas"
             case .voice: return "mic"
             case .memory: return "memorychip"
             case .auxiliary: return "sparkles.rectangle.stack"
@@ -171,6 +174,7 @@ struct SettingsView: View {
         case .agent:     AgentTab(viewModel: viewModel)
         case .terminal:  TerminalTab(viewModel: viewModel)
         case .browser:   BrowserTab(viewModel: viewModel)
+        case .webTools:  WebToolsTab(viewModel: viewModel)
         case .voice:     VoiceTab(viewModel: viewModel)
         case .memory:    MemoryTab(viewModel: viewModel)
         case .auxiliary: AuxiliaryTab(viewModel: viewModel)

scarf/scarf/Features/Settings/Views/Tabs/WebToolsTab.swift

@@ -0,0 +1,76 @@
+import SwiftUI
+import ScarfCore
+import ScarfDesign
+
+/// Web Tools tab — search + extract backend pickers. Pre-v0.13 hosts
+/// see a single "Combined backend" row writing to the legacy
+/// `web_tools.backend` key. v0.13+ hosts see two rows writing to the
+/// per-capability split keys (`web_tools.search.backend` +
+/// `web_tools.extract.backend`); SearXNG appears in the search picker
+/// only because Hermes registers it as a search-only backend.
+struct WebToolsTab: View {
+    @Bindable var viewModel: SettingsViewModel
+    @Environment(\.hermesCapabilities) private var capabilitiesStore
+
+    private var split: Bool {
+        capabilitiesStore?.capabilities.hasWebToolsBackendSplit ?? false
+    }
+
+    // TODO(WS-7-Q6): Backend lists are curated inline based on the v0.13
+    // release notes ("SearXNG joined search-only"). The exact dispatch
+    // table lives in `~/.hermes/hermes-agent/hermes_cli/web_tools.py` —
+    // verify during integration. A wrong entry just produces a
+    // `hermes config set` failure on save (recoverable, not silent).
+    private static let searchBackends: [String] = [
+        "duckduckgo", "tavily", "brave", "exa", "you", "searxng"
+    ]
+    private static let extractBackends: [String] = [
+        "reader", "browserless", "trafilatura", "firecrawl"
+    ]
+    /// v0.12 combined-backend list — superset of the v0.13 search list
+    /// minus SearXNG (which only dispatches as search) plus the v0.13
+    /// extract-only entries that pre-v0.13 hosts handled under the
+    /// combined key.
+    private static let combinedBackends: [String] = [
+        "duckduckgo", "tavily", "brave", "exa", "you",
+        "reader", "browserless", "trafilatura", "firecrawl"
+    ]
+
+    var body: some View {
+        if split {
+            SettingsSection(title: "Web Tools", icon: "globe.americas") {
+                PickerRow(
+                    label: "Search backend",
+                    selection: viewModel.config.webToolsSearchBackend,
+                    options: Self.searchBackends
+                ) { viewModel.setWebToolsSearchBackend($0) }
+                PickerRow(
+                    label: "Extract backend",
+                    selection: viewModel.config.webToolsExtractBackend,
+                    options: Self.extractBackends
+                ) { viewModel.setWebToolsExtractBackend($0) }
+            }
+            Text("SearXNG joined v0.13 as a search-only backend. Backend-specific tuning (host URLs, API keys) lives in the raw YAML editor for now.")
+                .scarfStyle(.caption)
+                .foregroundStyle(ScarfColor.foregroundMuted)
+                .padding(.horizontal, ScarfSpace.s4)
+        } else {
+            // TODO(WS-7-Q7): Pre-v0.13 hosts fall back to the legacy single
+            // backend. v0.13 may or may not honour `web_tools.backend` as a
+            // fallback when the split keys are absent — verify with Hermes
+            // and consider a one-time migration prompt in a follow-up if
+            // upgrading from v0.12 silently resets the user's backend.
+            SettingsSection(title: "Web Tools", icon: "globe.americas") {
+                PickerRow(
+                    label: "Backend",
+                    selection: viewModel.config.webToolsBackend,
+                    options: Self.combinedBackends
+                ) { viewModel.setWebToolsBackend($0) }
+            }
+            Text("Hermes v0.13 splits search and extract into separate backends. Update Hermes to access the per-capability picker.")
+                .scarfStyle(.caption)
+                .foregroundStyle(ScarfColor.foregroundFaint)
+                .padding(.horizontal, ScarfSpace.s4)
+        }
+    }
+}