Add cost metric and in-app update check.

- Activity dashboard gains a Cost unit: per-model input/output tokens are
  recorded and priced against a built-in API price table (ModelPricing), with a
  Requests/Tokens/Cost toggle. Cost is derived, not stored.
- About shows the app version (now read from Info.plist as the single source of
  truth) and a "Check for Updates" action that queries GitHub Releases and links
  to the download. No auto-update.
- build-app.sh can stamp a version into Info.plist; template bumped to 0.1.2.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: cailurus

Resources/Info.plist

@@ -2,32 +2,32 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
-    <key>CFBundleName</key>
-    <string>Copilot Bridge</string>
-    <key>CFBundleDisplayName</key>
-    <string>Copilot Bridge</string>
-    <key>CFBundleIdentifier</key>
-    <string>com.copilotbridge.app</string>
-    <key>CFBundleVersion</key>
-    <string>1</string>
-    <key>CFBundleShortVersionString</key>
-    <string>0.1.0</string>
-    <key>CFBundlePackageType</key>
-    <string>APPL</string>
-    <key>CFBundleExecutable</key>
-    <string>CopilotBridge</string>
-    <key>CFBundleIconFile</key>
-    <string>AppIcon</string>
-    <key>LSMinimumSystemVersion</key>
-    <string>14.0</string>
-    <key>LSUIElement</key>
-    <true/>
-    <key>NSHumanReadableCopyright</key>
-    <string>Copilot Bridge — local, uses your own GitHub Copilot subscription.</string>
-    <key>NSAppTransportSecurity</key>
-    <dict>
-        <key>NSAllowsLocalNetworking</key>
-        <true/>
-    </dict>
+	<key>CFBundleDisplayName</key>
+	<string>Copilot Bridge</string>
+	<key>CFBundleExecutable</key>
+	<string>CopilotBridge</string>
+	<key>CFBundleIconFile</key>
+	<string>AppIcon</string>
+	<key>CFBundleIdentifier</key>
+	<string>com.copilotbridge.app</string>
+	<key>CFBundleName</key>
+	<string>Copilot Bridge</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>0.1.2</string>
+	<key>CFBundleVersion</key>
+	<string>1</string>
+	<key>LSMinimumSystemVersion</key>
+	<string>14.0</string>
+	<key>LSUIElement</key>
+	<true/>
+	<key>NSAppTransportSecurity</key>
+	<dict>
+		<key>NSAllowsLocalNetworking</key>
+		<true/>
+	</dict>
+	<key>NSHumanReadableCopyright</key>
+	<string>Copilot Bridge — local, uses your own GitHub Copilot subscription.</string>
 </dict>
 </plist>

Sources/CopilotBridge/Core/ActivityStore.swift

@@ -13,14 +13,39 @@ import Foundation
 final class ActivityStore: ObservableObject {
     struct Stat: Codable, Equatable {
         var requests: Int = 0
+        /// Total tokens = input + output. Kept for the heatmap/back-compat.
         var tokens: Int = 0
+        var inputTokens: Int = 0
+        var outputTokens: Int = 0
+
+        init(requests: Int = 0, tokens: Int = 0, inputTokens: Int = 0, outputTokens: Int = 0) {
+            self.requests = requests
+            self.tokens = tokens
+            self.inputTokens = inputTokens
+            self.outputTokens = outputTokens
+        }
+
+        /// Tolerates older files that only had `requests`/`tokens` (split fields absent).
+        init(from decoder: Decoder) throws {
+            let c = try decoder.container(keyedBy: CodingKeys.self)
+            requests = (try? c.decode(Int.self, forKey: .requests)) ?? 0
+            tokens = (try? c.decode(Int.self, forKey: .tokens)) ?? 0
+            inputTokens = (try? c.decode(Int.self, forKey: .inputTokens)) ?? 0
+            outputTokens = (try? c.decode(Int.self, forKey: .outputTokens)) ?? 0
+        }
     }
 
     /// The metric the dashboard is currently showing.
     enum Unit: String, CaseIterable, Identifiable {
-        case requests, tokens
+        case requests, tokens, cost
         var id: String { rawValue }
-        var title: String { self == .requests ? "Requests" : "Tokens" }
+        var title: String {
+            switch self {
+            case .requests: return "Requests"
+            case .tokens: return "Tokens"
+            case .cost: return "Cost"
+            }
+        }
     }
 
     /// day (yyyy-MM-dd, local) -> model id -> stat
@@ -50,16 +75,20 @@ final class ActivityStore: ObservableObject {
         unit == .requests ? stat.requests : stat.tokens
     }
 
-    /// Records a batch of per-model request counts and token counts on the current local
-    /// day with a single save.
-    func record(requests: [String: Int], tokens: [String: Int], on date: Date = Date()) {
-        let models = Set(requests.keys).union(tokens.keys)
+    /// Records a batch of per-model request counts and input/output token counts on the
+    /// current local day with a single save.
+    func record(requests: [String: Int], inputTokens: [String: Int], outputTokens: [String: Int], on date: Date = Date()) {
+        let models = Set(requests.keys).union(inputTokens.keys).union(outputTokens.keys)
         guard !models.isEmpty else { return }
         let key = Self.dayKey(date)
         for model in models {
             var stat = days[key]?[model] ?? Stat()
+            let inTok = max(0, inputTokens[model] ?? 0)
+            let outTok = max(0, outputTokens[model] ?? 0)
             stat.requests += max(0, requests[model] ?? 0)
-            stat.tokens += max(0, tokens[model] ?? 0)
+            stat.inputTokens += inTok
+            stat.outputTokens += outTok
+            stat.tokens += inTok + outTok
             days[key, default: [:]][model] = stat
         }
         save()
@@ -94,6 +123,36 @@ final class ActivityStore: ObservableObject {
     /// Number of distinct days with at least one recorded model.
     var activeDays: Int { days.values.filter { !$0.isEmpty }.count }
 
+    // MARK: Cost aggregates (USD, derived from token split × ModelPricing)
+
+    private func cost(_ model: String, _ stat: Stat) -> Double {
+        ModelPricing.cost(model: model, inputTokens: stat.inputTokens, outputTokens: stat.outputTokens)
+    }
+
+    /// Estimated equivalent API cost (USD) across all history.
+    func costTotal() -> Double {
+        days.values.reduce(0) { acc, byModel in
+            acc + byModel.reduce(0) { $0 + cost($1.key, $1.value) }
+        }
+    }
+
+    /// Estimated cost for a given local day.
+    func cost(on date: Date) -> Double {
+        (days[Self.dayKey(date)]?.reduce(0) { $0 + cost($1.key, $1.value) }) ?? 0
+    }
+
+    /// Today's estimated cost.
+    func costToday() -> Double { cost(on: Date()) }
+
+    /// Per-model cost totals (USD), highest first.
+    func modelCostTotals() -> [(model: String, cost: Double)] {
+        var totals: [String: Double] = [:]
+        for byModel in days.values {
+            for (model, stat) in byModel { totals[model, default: 0] += cost(model, stat) }
+        }
+        return totals.sorted { $0.value > $1.value }.map { (model: $0.key, cost: $0.value) }
+    }
+
     // MARK: Persistence
 
     private func load() {

Sources/CopilotBridge/Core/AppState.swift

@@ -39,6 +39,8 @@ final class AppState: ObservableObject {
     /// Set after applying a Codex profile when prior threads use another provider,
     /// which drives the migration prompt sheet.
     @Published var pendingMigration: MigrationPrompt?
+    /// Latest update-check result, shown in About.
+    @Published private(set) var updateStatus: UpdateStatus = .idle
     let activity = ActivityStore()
 
     private let upstream: CopilotUpstream
@@ -99,6 +101,18 @@ final class AppState: ObservableObject {
                 startProxy()
             }
         }
+        checkForUpdates()
+    }
+
+    // MARK: Updates
+
+    func checkForUpdates() {
+        guard updateStatus != .checking else { return }
+        updateStatus = .checking
+        Task {
+            let result = await UpdateChecker.check(currentVersion: AppInfo.version)
+            self.updateStatus = result
+        }
     }
 
     var endpoint: ConfigWriter.Endpoint {
@@ -299,7 +313,7 @@ final class AppState: ObservableObject {
                 self.requestCount = count
                 self.lastError = err
                 let stats = await engine.drainModelStats()
-                self.activity.record(requests: stats.requests, tokens: stats.tokens)
+                self.activity.record(requests: stats.requests, inputTokens: stats.input, outputTokens: stats.output)
                 if let err {
                     self.lastActivity = "Last error: \(err.prefix(80))"
                 } else if count > 0 {

Sources/CopilotBridge/Core/ModelPricing.swift

@@ -0,0 +1,77 @@
+import Foundation
+
+/// Approximate official API list prices for estimating the *equivalent* cost of token
+/// usage. The user is on a fixed Copilot subscription, so this is a "what would these
+/// tokens cost at the underlying provider's API" figure, not a real bill.
+///
+/// Prices are USD per 1,000,000 tokens, input/output separate. These are approximate
+/// list prices as of 2026-07 and WILL drift — update the table when providers change
+/// pricing. Unknown models price at 0.
+struct ModelPrice: Equatable {
+    let inputPerM: Double
+    let outputPerM: Double
+}
+
+enum ModelPricing {
+    /// Keyed by a normalized model id (lowercased, `[1m]`/date suffix stripped).
+    static let table: [String: ModelPrice] = [
+        // OpenAI
+        "gpt-5": ModelPrice(inputPerM: 1.25, outputPerM: 10.0),
+        "gpt-5-mini": ModelPrice(inputPerM: 0.25, outputPerM: 2.0),
+        "gpt-4o": ModelPrice(inputPerM: 2.5, outputPerM: 10.0),
+        "gpt-4o-mini": ModelPrice(inputPerM: 0.15, outputPerM: 0.6),
+        "gpt-4.1": ModelPrice(inputPerM: 2.0, outputPerM: 8.0),
+        "gpt-4-turbo": ModelPrice(inputPerM: 10.0, outputPerM: 30.0),
+        "o1": ModelPrice(inputPerM: 15.0, outputPerM: 60.0),
+        "o3": ModelPrice(inputPerM: 2.0, outputPerM: 8.0),
+        "o4-mini": ModelPrice(inputPerM: 1.1, outputPerM: 4.4),
+        // Anthropic
+        "claude-opus-4": ModelPrice(inputPerM: 15.0, outputPerM: 75.0),
+        "claude-sonnet-4": ModelPrice(inputPerM: 3.0, outputPerM: 15.0),
+        "claude-haiku-4": ModelPrice(inputPerM: 0.8, outputPerM: 4.0),
+        // Google
+        "gemini-2.5-pro": ModelPrice(inputPerM: 1.25, outputPerM: 10.0),
+        "gemini-2.5-flash": ModelPrice(inputPerM: 0.3, outputPerM: 2.5),
+    ]
+
+    /// Cost in USD for a resolved model id and its input/output token split.
+    static func cost(model: String, inputTokens: Int, outputTokens: Int) -> Double {
+        guard let price = price(for: model) else { return 0 }
+        return Double(inputTokens) / 1_000_000 * price.inputPerM
+            + Double(outputTokens) / 1_000_000 * price.outputPerM
+    }
+
+    /// Resolves a price by exact normalized id, then by model family keywords.
+    static func price(for model: String) -> ModelPrice? {
+        let id = normalize(model)
+        if let exact = table[id] { return exact }
+
+        // Family fallback: match on family + size keyword so dated/suffixed ids still price.
+        if id.contains("claude") || id.contains("opus") || id.contains("sonnet") || id.contains("haiku") {
+            if id.contains("opus") { return table["claude-opus-4"] }
+            if id.contains("sonnet") { return table["claude-sonnet-4"] }
+            if id.contains("haiku") { return table["claude-haiku-4"] }
+        }
+        if id.contains("gemini") {
+            if id.contains("flash") { return table["gemini-2.5-flash"] }
+            return table["gemini-2.5-pro"]
+        }
+        if id.hasPrefix("gpt-5") { return id.contains("mini") ? table["gpt-5-mini"] : table["gpt-5"] }
+        if id.hasPrefix("gpt-4o") { return id.contains("mini") ? table["gpt-4o-mini"] : table["gpt-4o"] }
+        if id.hasPrefix("o1") { return table["o1"] }
+        if id.hasPrefix("o3") { return table["o3"] }
+        if id.hasPrefix("o4") { return table["o4-mini"] }
+        return nil
+    }
+
+    private static func normalize(_ model: String) -> String {
+        var id = model.lowercased()
+        if id.hasSuffix("[1m]") { id = String(id.dropLast(4)) }
+        // Strip a trailing 8-digit date, e.g. claude-3.5-sonnet-20240620.
+        let parts = id.split(separator: "-", omittingEmptySubsequences: false).map(String.init)
+        if let last = parts.last, last.count == 8, last.allSatisfy(\.isNumber) {
+            id = parts.dropLast().joined(separator: "-")
+        }
+        return id
+    }
+}

Sources/CopilotBridge/Core/Models.swift

@@ -141,3 +141,10 @@ func formatCompactCount(_ n: Int) -> String {
     }
     return "\(n)"
 }
+
+/// USD amount for the dashboard: `$0.00` under $1K, then `$1.2K` / `$3.4M`.
+func formatUSD(_ amount: Double) -> String {
+    if amount >= 1_000_000 { return String(format: "$%.1fM", amount / 1_000_000) }
+    if amount >= 1_000 { return String(format: "$%.1fK", amount / 1_000) }
+    return String(format: "$%.2f", amount)
+}

Sources/CopilotBridge/Core/UpdateChecker.swift

@@ -0,0 +1,79 @@
+import Foundation
+
+/// App metadata read from the bundle (single source of truth = Info.plist).
+enum AppInfo {
+    static var version: String {
+        (Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String) ?? "0.0.0"
+    }
+}
+
+/// Result of an update check, surfaced to the UI.
+enum UpdateStatus: Equatable {
+    case idle
+    case checking
+    case upToDate
+    case available(version: String, url: String)
+    case failed(String)
+}
+
+/// Checks GitHub Releases for a newer version. Manual/guided install only — this never
+/// downloads or replaces the app; it points the user at the release download.
+enum UpdateChecker {
+    static let latestReleaseURL = URL(string: "https://api.github.com/repos/cailurus/CopilotBridge/releases/latest")!
+
+    /// True if `remote` is a strictly higher semantic version than `local`.
+    /// Tolerant of a leading `v` and missing components (treated as 0).
+    static func isNewer(_ remote: String, than local: String) -> Bool {
+        let r = components(remote)
+        let l = components(local)
+        let n = max(r.count, l.count)
+        for i in 0..<n {
+            let rv = i < r.count ? r[i] : 0
+            let lv = i < l.count ? l[i] : 0
+            if rv != lv { return rv > lv }
+        }
+        return false
+    }
+
+    private static func components(_ version: String) -> [Int] {
+        version
+            .trimmingCharacters(in: .whitespaces)
+            .drop { $0 == "v" || $0 == "V" }
+            .split(separator: ".")
+            .map { Int($0.prefix { $0.isNumber }) ?? 0 }
+    }
+
+    /// Parses a GitHub `releases/latest` payload into a tag and a best download URL
+    /// (the `.dmg` asset if present, else the release page).
+    static func parseLatest(_ data: Data) -> (tag: String, downloadURL: String)? {
+        guard let obj = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
+              let tag = obj["tag_name"] as? String else { return nil }
+        let assets = obj["assets"] as? [[String: Any]] ?? []
+        let dmg = assets.first { ($0["name"] as? String)?.lowercased().hasSuffix(".dmg") == true }
+        let url = (dmg?["browser_download_url"] as? String)
+            ?? (obj["html_url"] as? String)
+            ?? "https://github.com/cailurus/CopilotBridge/releases/latest"
+        return (tag, url)
+    }
+
+    /// Fetches the latest release and compares it to `currentVersion`.
+    static func check(currentVersion: String) async -> UpdateStatus {
+        var req = URLRequest(url: latestReleaseURL, timeoutInterval: 8)
+        req.setValue("application/vnd.github+json", forHTTPHeaderField: "Accept")
+        req.setValue("CopilotBridge", forHTTPHeaderField: "User-Agent")   // GitHub requires a UA
+        do {
+            let (data, resp) = try await URLSession.shared.data(for: req)
+            guard let http = resp as? HTTPURLResponse, http.statusCode == 200 else {
+                return .failed("Update check failed (HTTP \((resp as? HTTPURLResponse)?.statusCode ?? -1))")
+            }
+            guard let parsed = parseLatest(data) else {
+                return .failed("Unexpected response from GitHub.")
+            }
+            return isNewer(parsed.tag, than: currentVersion)
+                ? .available(version: parsed.tag, url: parsed.downloadURL)
+                : .upToDate
+        } catch {
+            return .failed(error.localizedDescription)
+        }
+    }
+}