diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5a793cc..1ce3007 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -34,6 +34,29 @@ jobs:
         # non-mutating path.
         run: python3 scripts/preflight.py
 
+  linux-build-and-test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Swift
+        uses: swift-actions/setup-swift@v2
+        with:
+          swift-version: "6.0.3"
+
+      - name: Cache SwiftPM
+        uses: actions/cache@v4
+        with:
+          path: |
+            .build
+            ~/.cache/org.swift.swiftpm
+          key: ${{ runner.os }}-swiftpm-${{ hashFiles('Package.resolved') }}
+          restore-keys: |
+            ${{ runner.os }}-swiftpm-
+
+      - name: Preflight (Linux, no GUI/TCC)
+        run: python3 scripts/preflight.py --bin .build/debug/computer-use-mcp
+
   # Non-blocking style check: does not gate build-and-test. Prefer the
   # toolchain-bundled `swift format lint` over adding a SwiftLint dependency.
   lint:
diff --git a/README.md b/README.md
index 7cf8271..f21b6ea 100644
--- a/README.md
+++ b/README.md
@@ -13,10 +13,11 @@ server. Point Claude Code, Cursor, Codex CLI, Gemini CLI, or your own agent at i
 and the agent can **see and operate the apps on your Mac — in the background,
 without hijacking your cursor or stealing focus.**
 
-> **Status:** pre-1.0, used in production by the authors. macOS only. Runs while
-> the Mac is unlocked (the system is kept from idle-sleeping during active
-> sessions; if the screen locks, mutating tools pause with a recoverable error
-> until you unlock).
+> **Status:** pre-1.0, used in production by the authors. The interaction engine
+> runs on macOS while the Linux build, tests, CLI, and daemon plumbing are
+> supported. On macOS it runs while the Mac is unlocked (the system is kept from
+> idle-sleeping during active sessions; if the screen locks, mutating tools pause
+> with a recoverable error until you unlock).
 
 <!--
   HERO MEDIA PLACEHOLDER.
@@ -417,6 +418,8 @@ Two ways to keep large windows from blowing up the tree:
   (Input Monitoring is *not* required). Run `computer-use-mcp health_report` to
   inspect current identity/permission state, or `computer-use-mcp doctor --prompt`
   when you intentionally want macOS prompts.
+- Linux: Swift 6.0.3 for build, tests, CLI, and daemon use; no GUI permissions
+  are required.
 
 ## Safety
 
@@ -518,8 +521,9 @@ productionization checklist.
   `allow_global_cursor: true` as an explicit fallback.
 - Menu key-equivalents (e.g. `cmd+a`) are reliable when the app is the key window;
   some apps ignore them when targeted purely in the background.
-- macOS only (the engine is built on Accessibility, ScreenCaptureKit, and
-  CoreGraphics). The protocol/tool layer is OS-agnostic.
+- The interaction engine is macOS-only (Accessibility, ScreenCaptureKit, and
+  CoreGraphics). Linux tools that require those capabilities return structured
+  unsupported errors; the protocol/tool layer is OS-agnostic.
 
 ## Development
 
diff --git a/Sources/ComputerUseFixture/ComputerUseFixtureApp.swift b/Sources/ComputerUseFixture/ComputerUseFixtureApp.swift
index ba96407..b721225 100644
--- a/Sources/ComputerUseFixture/ComputerUseFixtureApp.swift
+++ b/Sources/ComputerUseFixture/ComputerUseFixtureApp.swift
@@ -1,3 +1,4 @@
+#if os(macOS)
 import AppKit
 import SwiftUI
 
@@ -96,3 +97,11 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
         DispatchQueue.main.async { NSApp.deactivate() }
     }
 }
+#else
+import Foundation
+
+@main
+struct ComputerUseFixtureApp {
+    static func main() {}
+}
+#endif
diff --git a/Sources/ComputerUseFixture/ContentView.swift b/Sources/ComputerUseFixture/ContentView.swift
index 947b77c..af85535 100644
--- a/Sources/ComputerUseFixture/ContentView.swift
+++ b/Sources/ComputerUseFixture/ContentView.swift
@@ -1,3 +1,4 @@
+#if os(macOS)
 import SwiftUI
 
 struct ContentView: View {
@@ -79,3 +80,4 @@ struct ContentView: View {
         .background(RoundedRectangle(cornerRadius: 8).fill(Color.gray.opacity(0.08)))
     }
 }
+#endif
diff --git a/Sources/ComputerUseFixture/FixtureComponents.swift b/Sources/ComputerUseFixture/FixtureComponents.swift
index affd898..116213c 100644
--- a/Sources/ComputerUseFixture/FixtureComponents.swift
+++ b/Sources/ComputerUseFixture/FixtureComponents.swift
@@ -1,3 +1,4 @@
+#if os(macOS)
 import AppKit
 import SwiftUI
 
@@ -79,3 +80,4 @@ final class LiarButtonView: NSView {
             withAttributes: attrs)
     }
 }
+#endif
diff --git a/Sources/ComputerUseFixture/KeystrokeInput.swift b/Sources/ComputerUseFixture/KeystrokeInput.swift
index 87ec0a6..755792a 100644
--- a/Sources/ComputerUseFixture/KeystrokeInput.swift
+++ b/Sources/ComputerUseFixture/KeystrokeInput.swift
@@ -1,3 +1,4 @@
+#if os(macOS)
 import AppKit
 import SwiftUI
 
@@ -68,3 +69,4 @@ final class KeystrokeView: NSView {
         display.draw(at: NSPoint(x: 6, y: (bounds.height - 18) / 2), withAttributes: attrs)
     }
 }
+#endif
diff --git a/Sources/ComputerUseFixture/RowListPane.swift b/Sources/ComputerUseFixture/RowListPane.swift
index 11ff210..debaa9b 100644
--- a/Sources/ComputerUseFixture/RowListPane.swift
+++ b/Sources/ComputerUseFixture/RowListPane.swift
@@ -1,3 +1,4 @@
+#if os(macOS)
 import AppKit
 import SwiftUI
 
@@ -54,7 +55,7 @@ struct AppKitRowList: NSViewRepresentable {
 
     func updateNSView(_ nsView: NSScrollView, context: Context) {}
 
-    final class Coordinator: NSObject, NSTableViewDataSource, NSTableViewDelegate {
+final class Coordinator: NSObject, NSTableViewDataSource, NSTableViewDelegate {
         func numberOfRows(in tableView: NSTableView) -> Int { rowCount }
 
         func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView? {
@@ -72,3 +73,4 @@ struct AppKitRowList: NSViewRepresentable {
         }
     }
 }
+#endif
diff --git a/Sources/ComputerUseFixture/ScrollProbePane.swift b/Sources/ComputerUseFixture/ScrollProbePane.swift
index 159768f..8abb63f 100644
--- a/Sources/ComputerUseFixture/ScrollProbePane.swift
+++ b/Sources/ComputerUseFixture/ScrollProbePane.swift
@@ -1,3 +1,4 @@
+#if os(macOS)
 import AppKit
 import SwiftUI
 
@@ -71,3 +72,4 @@ final class InertScrollTargetView: NSView {
         }
     }
 }
+#endif
diff --git a/Sources/ComputerUseFixture/WebPane.swift b/Sources/ComputerUseFixture/WebPane.swift
index 6dce30c..d02e703 100644
--- a/Sources/ComputerUseFixture/WebPane.swift
+++ b/Sources/ComputerUseFixture/WebPane.swift
@@ -1,3 +1,4 @@
+#if os(macOS)
 import SwiftUI
 import WebKit
 
@@ -46,3 +47,4 @@ struct WebPane: NSViewRepresentable {
         </html>
         """
 }
+#endif
diff --git a/Sources/computer-use-mcp/Core/AX.swift b/Sources/computer-use-mcp/Core/AX.swift
index efcc5ea..8629e44 100644
--- a/Sources/computer-use-mcp/Core/AX.swift
+++ b/Sources/computer-use-mcp/Core/AX.swift
@@ -1,8 +1,10 @@
 // Thin helpers over the C Accessibility (AXUIElement) API.
 
+import Foundation
+#if os(macOS)
 import AppKit
 import ApplicationServices
-import Foundation
+#endif
 
 /// Process-wide AX messaging timeout (seconds). An unresponsive app then
 /// fails each AX call after this bound instead of stalling tool calls for the
diff --git a/Sources/computer-use-mcp/Core/ActionChains.swift b/Sources/computer-use-mcp/Core/ActionChains.swift
index fed10bc..15e4418 100644
--- a/Sources/computer-use-mcp/Core/ActionChains.swift
+++ b/Sources/computer-use-mcp/Core/ActionChains.swift
@@ -14,9 +14,11 @@
 // chains can be added later without new plumbing. Inspired by
 // lahfir/agent-desktop's chain_defs.rs, adapted to our verifier.
 
+import Foundation
+#if os(macOS)
 import ApplicationServices
 import CoreGraphics
-import Foundation
+#endif
 
 // MARK: - Chain definition (data-driven)
 
diff --git a/Sources/computer-use-mcp/Core/ActionOutcome.swift b/Sources/computer-use-mcp/Core/ActionOutcome.swift
index e3c8fb0..3a686bb 100644
--- a/Sources/computer-use-mcp/Core/ActionOutcome.swift
+++ b/Sources/computer-use-mcp/Core/ActionOutcome.swift
@@ -8,9 +8,11 @@
 //
 // See docs/outcome-contract.md for the design and the per-tool trap matrix.
 
-import ApplicationServices
 import Foundation
 import MCP
+#if os(macOS)
+import ApplicationServices
+#endif
 
 let actionOutcomeMetaKey = "computer-use-mcp/outcome"
 
diff --git a/Sources/computer-use-mcp/Core/AppResolver.swift b/Sources/computer-use-mcp/Core/AppResolver.swift
index 36ec44e..a57ed3e 100644
--- a/Sources/computer-use-mcp/Core/AppResolver.swift
+++ b/Sources/computer-use-mcp/Core/AppResolver.swift
@@ -1,8 +1,10 @@
 // Resolve a target app by name or bundle identifier, and enumerate
 // controllable apps.
 
-import AppKit
 import Foundation
+#if os(macOS)
+import AppKit
+#endif
 
 struct ResolvedApp {
     let pid: pid_t
@@ -61,10 +63,17 @@ private final class RunningApplicationsCache: @unchecked Sendable {
 /// pid size silently dropped the oldest three quarters of the list and made
 /// login-time apps unresolvable.
 func allProcessIDs() -> [pid_t] {
+    #if os(macOS)
     var pids = [pid_t](repeating: 0, count: 8192)
     let returned = proc_listallpids(&pids, Int32(pids.count * MemoryLayout<pid_t>.size))
     guard returned > 0 else { return [] }
     return pids.prefix(min(Int(returned), pids.count)).filter { $0 > 0 }
+    #else
+    (try? FileManager.default.contentsOfDirectory(atPath: "/proc"))?.compactMap { entry in
+        guard entry.allSatisfy(\.isNumber), let pid = Int32(entry), pid > 0 else { return nil }
+        return pid
+    } ?? []
+    #endif
 }
 
 func resolveApp(_ identifier: String) throws -> ResolvedApp {
diff --git a/Sources/computer-use-mcp/Core/FocusTelemetry.swift b/Sources/computer-use-mcp/Core/FocusTelemetry.swift
index 0ff9e16..af70310 100644
--- a/Sources/computer-use-mcp/Core/FocusTelemetry.swift
+++ b/Sources/computer-use-mcp/Core/FocusTelemetry.swift
@@ -1,7 +1,9 @@
-import AppKit
-import ApplicationServices
 import Foundation
 import MCP
+#if os(macOS)
+import AppKit
+import ApplicationServices
+#endif
 
 private let focusTelemetryMetaKey = "computer-use-mcp/focus"
 private let deliveryTelemetryMetaKey = "computer-use-mcp/delivery"
diff --git a/Sources/computer-use-mcp/Core/GeometrySanitization.swift b/Sources/computer-use-mcp/Core/GeometrySanitization.swift
index bc07c36..27fc84f 100644
--- a/Sources/computer-use-mcp/Core/GeometrySanitization.swift
+++ b/Sources/computer-use-mcp/Core/GeometrySanitization.swift
@@ -1,4 +1,5 @@
-import CoreGraphics
+
+import Foundation
 
 /// Geometry from AX/CoreGraphics/JavaScript can cross process boundaries with
 /// NaN or infinite components. Swift traps when such values are converted to
diff --git a/Sources/computer-use-mcp/Core/HitTest.swift b/Sources/computer-use-mcp/Core/HitTest.swift
index 8589c1d..fa93d1c 100644
--- a/Sources/computer-use-mcp/Core/HitTest.swift
+++ b/Sources/computer-use-mcp/Core/HitTest.swift
@@ -1,8 +1,10 @@
 // Coordinate → element hit-testing, the fallback when a target is not (or is
 // wrongly) represented in the accessibility tree.
 
-import ApplicationServices
 import Foundation
+#if os(macOS)
+import ApplicationServices
+#endif
 
 /// The accessibility element at a global screen point, restricted to the
 /// target app. Returns nil when nothing (or another app's window) is there.
diff --git a/Sources/computer-use-mcp/Core/Input.swift b/Sources/computer-use-mcp/Core/Input.swift
index bf90e66..a8b8c6b 100644
--- a/Sources/computer-use-mcp/Core/Input.swift
+++ b/Sources/computer-use-mcp/Core/Input.swift
@@ -1,3 +1,4 @@
+ #if os(macOS)
 // Background-safe synthetic input delivery.
 //
 // The ladder, in order of preference, for delivering a mouse/scroll/key event
@@ -15,10 +16,12 @@
 // there is no reliable success signal, so escalation to Tier 4 is never
 // automatic — it requires the caller's explicit opt-in.
 
+import Foundation
+#if os(macOS)
 import AppKit
 import ApplicationServices
 import CoreGraphics
-import Foundation
+#endif
 
 // Private SPI mapping an AX window element to its CGWindowID, used as the
 // NSEvent windowNumber. Undocumented but stable; always guard the result.
@@ -495,3 +498,4 @@ func deliverKey(_ chord: KeyChord, context: DeliveryContext, targetAppIsActive:
     }
     return mode
 }
+#endif
diff --git a/Sources/computer-use-mcp/Core/InterferenceGuard.swift b/Sources/computer-use-mcp/Core/InterferenceGuard.swift
index 441f571..1c01895 100644
--- a/Sources/computer-use-mcp/Core/InterferenceGuard.swift
+++ b/Sources/computer-use-mcp/Core/InterferenceGuard.swift
@@ -13,9 +13,11 @@
 // delivery (private-source events posted to a pid or window) does not update —
 // the agent cannot trip its own guard.
 
-import CoreGraphics
 import Foundation
 import MCP
+#if os(macOS)
+import CoreGraphics
+#endif
 
 /// Pure yield decision, separated from system state for tests.
 func interferenceShouldYield(
diff --git a/Sources/computer-use-mcp/Core/Keymap.swift b/Sources/computer-use-mcp/Core/Keymap.swift
index 040f3f7..de4eb10 100644
--- a/Sources/computer-use-mcp/Core/Keymap.swift
+++ b/Sources/computer-use-mcp/Core/Keymap.swift
@@ -1,11 +1,14 @@
+ #if os(macOS)
 // Parse xdotool-style key strings ("cmd+shift+s", "Return", "a") into a
 // CGKeyCode + modifier flags. Named keys use layout-independent virtual
 // keycodes; printable characters are translated against the current keyboard
 // layout via UCKeyTranslate.
 
+import Foundation
+#if os(macOS)
 import Carbon.HIToolbox
 import CoreGraphics
-import Foundation
+#endif
 
 struct KeyChord {
     let keyCode: CGKeyCode
@@ -138,3 +141,4 @@ enum Keymap {
         return String(utf16CodeUnits: chars, count: length)
     }
 }
+#endif
diff --git a/Sources/computer-use-mcp/Core/OCR.swift b/Sources/computer-use-mcp/Core/OCR.swift
index f7ed3b5..ab813be 100644
--- a/Sources/computer-use-mcp/Core/OCR.swift
+++ b/Sources/computer-use-mcp/Core/OCR.swift
@@ -3,9 +3,11 @@
 // accessibility tree is missing or empty — custom-drawn UIs, games,
 // remote-desktop and virtualization windows.
 
-import CoreGraphics
 import Foundation
+#if os(macOS)
+import CoreGraphics
 import Vision
+#endif
 
 struct OCRLine: Sendable {
     let text: String
@@ -13,6 +15,7 @@ struct OCRLine: Sendable {
     let box: [Int]
 }
 
+ #if os(macOS)
 func recognizeText(inPNG pngData: Data, pixelWidth: Int, pixelHeight: Int) async throws -> [OCRLine] {
     let request = VNRecognizeTextRequest()
     request.recognitionLevel = .accurate
@@ -31,6 +34,11 @@ func recognizeText(inPNG pngData: Data, pixelWidth: Int, pixelHeight: Int) async
         }
     }.value
 }
+#else
+func recognizeText(inPNG pngData: Data, pixelWidth: Int, pixelHeight: Int) async throws -> [OCRLine] {
+    throw ToolError.failed("OCR is unsupported on Linux.")
+}
+#endif
 
 /// Vision boxes are normalized with a bottom-left origin; screenshots use
 /// top-left pixel coordinates.
diff --git a/Sources/computer-use-mcp/Core/PointTarget.swift b/Sources/computer-use-mcp/Core/PointTarget.swift
index a3a93ef..fdf9712 100644
--- a/Sources/computer-use-mcp/Core/PointTarget.swift
+++ b/Sources/computer-use-mcp/Core/PointTarget.swift
@@ -1,10 +1,12 @@
 // Shared resolution for pointer tools (click, scroll): turn the tool args into
 // a concrete (AXUIElement, global point, delivery context).
 
-import ApplicationServices
-import CoreGraphics
 import Foundation
 import MCP
+#if os(macOS)
+import ApplicationServices
+import CoreGraphics
+#endif
 
 struct PointTarget {
     /// The element under the point (hit-tested or resolved from an id), if any.
diff --git a/Sources/computer-use-mcp/Core/SafetyPolicy.swift b/Sources/computer-use-mcp/Core/SafetyPolicy.swift
index 625677b..d04f642 100644
--- a/Sources/computer-use-mcp/Core/SafetyPolicy.swift
+++ b/Sources/computer-use-mcp/Core/SafetyPolicy.swift
@@ -12,10 +12,12 @@
 //   COMPUTER_USE_MCP_CONFIRM_APPS=a,b,c     apps where every action needs confirm
 //   COMPUTER_USE_MCP_DESTRUCTIVE=pat,pat    extra destructive label substrings
 
+import Foundation
+#if os(macOS)
 import ApplicationServices
 import Carbon.HIToolbox
 import CoreGraphics
-import Foundation
+#endif
 import MCP
 
 struct SafetyError: Error, CustomStringConvertible {
diff --git a/Sources/computer-use-mcp/Core/Screenshot.swift b/Sources/computer-use-mcp/Core/Screenshot.swift
index cdb2e99..c5fd474 100644
--- a/Sources/computer-use-mcp/Core/Screenshot.swift
+++ b/Sources/computer-use-mcp/Core/Screenshot.swift
@@ -1,11 +1,13 @@
 // Window screenshots via ScreenCaptureKit. Captures a single app window
 // without bringing it to the foreground.
 
-import CoreGraphics
 import Foundation
+#if os(macOS)
+import CoreGraphics
 import ImageIO
 @preconcurrency import ScreenCaptureKit
 import UniformTypeIdentifiers
+#endif
 
 struct WindowCapture {
     let pngData: Data
@@ -37,6 +39,7 @@ enum ScreenshotDetail: Sendable {
     }
 }
 
+#if os(macOS)
 func captureWindow(pid: pid_t, title: String?, frame: CGRect, detail: ScreenshotDetail) async throws -> WindowCapture {
     guard CGPreflightScreenCaptureAccess() else {
         throw ToolError.failed(
@@ -59,7 +62,6 @@ func captureWindow(pid: pid_t, title: String?, frame: CGRect, detail: Screenshot
         }
     }
 }
-
 /// SCShareableContent enumerates every shareable window in the system through
 /// replayd — the most expensive part of a capture. Within a burst of actions
 /// the window list barely changes, so it is cached briefly; a request the
@@ -237,3 +239,8 @@ private func encodePNG(_ image: CGImage) -> Data? {
     guard CGImageDestinationFinalize(destination) else { return nil }
     return data as Data
 }
+#else
+func captureWindow(pid: pid_t, title: String?, frame: CGRect, detail: ScreenshotDetail) async throws -> WindowCapture {
+    throw ToolError.failed("Screenshots are unsupported on Linux.")
+}
+#endif
diff --git a/Sources/computer-use-mcp/Core/ScrollRouting.swift b/Sources/computer-use-mcp/Core/ScrollRouting.swift
index 2ce708b..78bede6 100644
--- a/Sources/computer-use-mcp/Core/ScrollRouting.swift
+++ b/Sources/computer-use-mcp/Core/ScrollRouting.swift
@@ -6,9 +6,11 @@
 // scrollability, and drive the highest-ranked container (special-casing web
 // areas). Mirrors BCU's ScrollRouteService, tuned to what our trees expose.
 
+import Foundation
+#if os(macOS)
 import ApplicationServices
 import CoreGraphics
-import Foundation
+#endif
 
 /// Extracted, side-effect-free features of a scroll-container candidate, so the
 /// scoring policy is a pure function separate from the live AX reads.
diff --git a/Sources/computer-use-mcp/Core/SessionPower.swift b/Sources/computer-use-mcp/Core/SessionPower.swift
index 346dbae..07c9e1d 100644
--- a/Sources/computer-use-mcp/Core/SessionPower.swift
+++ b/Sources/computer-use-mcp/Core/SessionPower.swift
@@ -8,9 +8,11 @@
 // an invisible session (unlocking is the user's decision — no Codex-style
 // auto-unlock behind a fake lock screen).
 
-import CoreGraphics
 import Foundation
+#if os(macOS)
+import CoreGraphics
 import IOKit.pwr_mgt
+#endif
 
 /// Recoverable pause for mutating tools while the screen is locked.
 /// Read-only perception stays available. `isLocked` is an autoclosure so the
diff --git a/Sources/computer-use-mcp/Core/SkyLightInput.swift b/Sources/computer-use-mcp/Core/SkyLightInput.swift
index 2a53c3a..23a86c6 100644
--- a/Sources/computer-use-mcp/Core/SkyLightInput.swift
+++ b/Sources/computer-use-mcp/Core/SkyLightInput.swift
@@ -1,6 +1,8 @@
+import Foundation
+#if os(macOS)
 import CoreGraphics
 import Darwin
-import Foundation
+#endif
 
 private let skyLightFrameworkPath = "/System/Library/PrivateFrameworks/SkyLight.framework/SkyLight"
 
diff --git a/Sources/computer-use-mcp/Core/Snapshot.swift b/Sources/computer-use-mcp/Core/Snapshot.swift
index be916df..815e88a 100644
--- a/Sources/computer-use-mcp/Core/Snapshot.swift
+++ b/Sources/computer-use-mcp/Core/Snapshot.swift
@@ -10,9 +10,11 @@
 // Snapshots are persisted to disk so ids work across processes (the `serve`
 // server and the `call` harness, or a restarted server).
 
+import Foundation
+#if os(macOS)
 import ApplicationServices
 import CryptoKit
-import Foundation
+#endif
 
 struct LocatorStep: Codable, Equatable {
     let role: String
@@ -434,8 +436,17 @@ actor SnapshotStore {
 /// generation tags.
 func treeFingerprint(_ treeText: String) -> String {
     let normalized = treeText.replacing(/e\d+@s\d+/, with: "e@")
+    #if os(macOS)
     let digest = SHA256.hash(data: Data(normalized.utf8))
     return digest.map { String(format: "%02x", $0) }.joined()
+    #else
+    var hash: UInt64 = 14695981039346656037
+    for byte in normalized.utf8 {
+        hash ^= UInt64(byte)
+        hash &*= 1099511628211
+    }
+    return String(format: "%016llx", hash)
+    #endif
 }
 
 /// What changed between the previous snapshot and a fresh capture, after id
diff --git a/Sources/computer-use-mcp/Core/Target.swift b/Sources/computer-use-mcp/Core/Target.swift
index 31b6487..66d5212 100644
--- a/Sources/computer-use-mcp/Core/Target.swift
+++ b/Sources/computer-use-mcp/Core/Target.swift
@@ -1,9 +1,11 @@
 // Shared target resolution for interaction tools: app + element_id (from the
 // latest snapshot) → live AXUIElement, re-resolved via its locator path.
 
-import ApplicationServices
 import Foundation
 import MCP
+#if os(macOS)
+import ApplicationServices
+#endif
 
 struct ResolvedTarget {
     let app: ResolvedApp
diff --git a/Sources/computer-use-mcp/Core/TextExtraction.swift b/Sources/computer-use-mcp/Core/TextExtraction.swift
index 0e27b90..e5863a5 100644
--- a/Sources/computer-use-mcp/Core/TextExtraction.swift
+++ b/Sources/computer-use-mcp/Core/TextExtraction.swift
@@ -1,3 +1,4 @@
+ #if os(macOS)
 // Visible-range and rich-text extraction for read_text.
 //
 // A large text surface (a long article, an editor buffer) can hold far more
@@ -8,9 +9,11 @@
 // and renders the attributed runs to lightweight markdown so links and
 // emphasis survive as text (BCU-style extraction).
 
+import Foundation
+#if os(macOS)
 import AppKit
 import ApplicationServices
-import Foundation
+#endif
 
 enum TextExtraction {
     /// Character count above which read_text auto-switches to the visible-range
@@ -142,8 +145,9 @@ private func linkURL(from attributes: [NSAttributedString.Key: Any]) -> String?
             let element = ref as! AXUIElement
             if let url = axString(element, kAXURLAttribute), !url.isEmpty { return url }
         }
-        if let url = value as? URL { return url.absoluteString }
-        if let string = value as? String, !string.isEmpty { return string }
+    if let url = value as? URL { return url.absoluteString }
+    if let string = value as? String, !string.isEmpty { return string }
     }
     return nil
 }
+#endif
diff --git a/Sources/computer-use-mcp/Core/TreeBuilder.swift b/Sources/computer-use-mcp/Core/TreeBuilder.swift
index 5da02b6..8334ae8 100644
--- a/Sources/computer-use-mcp/Core/TreeBuilder.swift
+++ b/Sources/computer-use-mcp/Core/TreeBuilder.swift
@@ -6,8 +6,10 @@
 // dense-collection viewport windowing, and skeleton depth truncation — are
 // unit-testable against an in-memory tree with no live accessibility API.
 
-import ApplicationServices
 import Foundation
+#if os(macOS)
+import ApplicationServices
+#endif
 
 struct BuiltTree {
     let text: String
diff --git a/Sources/computer-use-mcp/Core/URLPolicy.swift b/Sources/computer-use-mcp/Core/URLPolicy.swift
index 8074fd1..370c521 100644
--- a/Sources/computer-use-mcp/Core/URLPolicy.swift
+++ b/Sources/computer-use-mcp/Core/URLPolicy.swift
@@ -9,9 +9,11 @@
 // Substring match, case-insensitive. open_url applies the same patterns to
 // its URL argument directly.
 
-import ApplicationServices
 import Foundation
 import MCP
+#if os(macOS)
+import ApplicationServices
+#endif
 
 let browserBundleIdentifiers: Set<String> = [
     "com.apple.safari", "com.apple.safaritechnologypreview",
diff --git a/Sources/computer-use-mcp/Core/Window.swift b/Sources/computer-use-mcp/Core/Window.swift
index f2873b4..033fc10 100644
--- a/Sources/computer-use-mcp/Core/Window.swift
+++ b/Sources/computer-use-mcp/Core/Window.swift
@@ -1,8 +1,10 @@
 // Target-window selection for an app: front window by default, or by title.
 
+import Foundation
+#if os(macOS)
 import ApplicationServices
 import CoreGraphics
-import Foundation
+#endif
 
 /// Backing scale of the display containing a global top-left point — the
 /// fallback pixels-per-point when a window cannot be captured and no prior
diff --git a/Sources/computer-use-mcp/Core/WindowMotion.swift b/Sources/computer-use-mcp/Core/WindowMotion.swift
index 8f0c20c..e211716 100644
--- a/Sources/computer-use-mcp/Core/WindowMotion.swift
+++ b/Sources/computer-use-mcp/Core/WindowMotion.swift
@@ -16,9 +16,11 @@
 // the corrective write, sleeping) is injected — so the logic is unit-tested
 // without a live window. The live wiring lives in Tools/SystemTools.swift.
 
+import Foundation
+#if os(macOS)
 import ApplicationServices
 import CoreGraphics
-import Foundation
+#endif
 
 enum WindowMotion {
     // MARK: - Tunables
diff --git a/Sources/computer-use-mcp/Daemon/DaemonClient.swift b/Sources/computer-use-mcp/Daemon/DaemonClient.swift
index bacfc19..eb7e9d5 100644
--- a/Sources/computer-use-mcp/Daemon/DaemonClient.swift
+++ b/Sources/computer-use-mcp/Daemon/DaemonClient.swift
@@ -6,6 +6,11 @@
 
 import Foundation
 import MCP
+#if os(Linux)
+import Glibc
+#else
+import Darwin
+#endif
 
 actor DaemonClient {
     static let shared = DaemonClient()
@@ -98,7 +103,11 @@ actor DaemonClient {
     }
 
     private static func connect() -> Int32? {
+        #if os(Linux)
+        let fd = socket(AF_UNIX, Int32(SOCK_STREAM.rawValue), 0)
+        #else
         let fd = socket(AF_UNIX, SOCK_STREAM, 0)
+        #endif
         guard fd >= 0 else { return nil }
         var address = sockaddr_un()
         address.sun_family = sa_family_t(AF_UNIX)
@@ -114,7 +123,11 @@ actor DaemonClient {
         let result = fits
             ? withUnsafePointer(to: &address) { pointer in
                 pointer.withMemoryRebound(to: sockaddr.self, capacity: 1) {
+                    #if os(Linux)
+                    SwiftGlibc.connect(fd, $0, size)
+                    #else
                     Darwin.connect(fd, $0, size)
+                    #endif
                 }
             } : -1
         guard result == 0 else {
diff --git a/Sources/computer-use-mcp/Daemon/DaemonProtocol.swift b/Sources/computer-use-mcp/Daemon/DaemonProtocol.swift
index 947b6f9..1e589dc 100644
--- a/Sources/computer-use-mcp/Daemon/DaemonProtocol.swift
+++ b/Sources/computer-use-mcp/Daemon/DaemonProtocol.swift
@@ -3,8 +3,12 @@
 // connection is the session identity for app leases.
 
 import Foundation
-import Security
 import MCP
+#if os(macOS)
+import Security
+#else
+import Glibc
+#endif
 
 func daemonSocketPath() -> String {
     daemonRuntimePaths().socket
@@ -390,12 +394,18 @@ private func readDaemonAuthToken(path: String) -> String? {
 
 private func generateDaemonAuthToken() throws -> String {
     var bytes = [UInt8](repeating: 0, count: 32)
+    #if os(macOS)
     let status = bytes.withUnsafeMutableBytes { buffer in
         SecRandomCopyBytes(kSecRandomDefault, buffer.count, buffer.baseAddress!)
     }
     guard status == errSecSuccess else {
         throw DaemonAuthError.randomFailed
     }
+    #else
+    for index in bytes.indices {
+        bytes[index] = UInt8.random(in: .min ... .max)
+    }
+    #endif
     return Data(bytes).base64EncodedString()
 }
 
diff --git a/Sources/computer-use-mcp/Daemon/DaemonServer.swift b/Sources/computer-use-mcp/Daemon/DaemonServer.swift
index 382f632..35f69f6 100644
--- a/Sources/computer-use-mcp/Daemon/DaemonServer.swift
+++ b/Sources/computer-use-mcp/Daemon/DaemonServer.swift
@@ -7,9 +7,13 @@
 // shared system services, and per-app leases (AppLeases) keep two sessions
 // from interleaving actions inside the same app.
 
-import Darwin
 import Foundation
 import MCP
+#if os(Linux)
+import Glibc
+#else
+import Darwin
+#endif
 
 private let daemonConnectionLimiter = DaemonConnectionLimiter(maxConnections: DaemonProtocolLimits.maxConcurrentConnections)
 
@@ -84,7 +88,11 @@ func runDaemon() async -> Never {
 private func bindDaemonSocket() -> Int32 {
     let path = daemonSocketPath()
     unlink(path)  // stale socket from a dead daemon; the lock arbitrates liveness
+    #if os(Linux)
+    let fd = socket(AF_UNIX, Int32(SOCK_STREAM.rawValue), 0)
+    #else
     let fd = socket(AF_UNIX, SOCK_STREAM, 0)
+    #endif
     guard fd >= 0 else { fatalError("daemon: socket() failed: \(errno)") }
 
     var address = sockaddr_un()
@@ -111,12 +119,27 @@ private func bindDaemonSocket() -> Int32 {
 }
 
 private func isTrustedPeer(_ fd: Int32) -> Bool {
+    #if os(Linux)
+    var credentials = LinuxPeerCredentials()
+    var length = socklen_t(MemoryLayout<LinuxPeerCredentials>.size)
+    let result = withUnsafeMutablePointer(to: &credentials) { pointer in
+        getsockopt(
+            fd,
+            Int32(SOL_SOCKET),
+            Int32(SO_PEERCRED),
+            pointer,
+            &length
+        )
+    }
+    return result == 0 && credentials.uid == geteuid()
+    #else
     var uid: uid_t = 0
     var gid: gid_t = 0
     guard getpeereid(fd, &uid, &gid) == 0 else {
         return false
     }
     return uid == geteuid()
+    #endif
 }
 
 private func serveConnection(fd: Int32, authToken: String, connectionTasks: DaemonConnectionTasks) {
diff --git a/Sources/computer-use-mcp/HealthReport.swift b/Sources/computer-use-mcp/HealthReport.swift
index 3998616..ac6fc5d 100644
--- a/Sources/computer-use-mcp/HealthReport.swift
+++ b/Sources/computer-use-mcp/HealthReport.swift
@@ -1,11 +1,16 @@
+import Foundation
+#if os(macOS)
 import AppKit
 import ApplicationServices
 import CoreGraphics
 import Darwin
-import Foundation
 import ScreenCaptureKit
+#else
+import Glibc
+#endif
 
 func makeHealthReport(prompt: Bool, probeCaptureService: Bool) async -> HealthReport {
+    #if os(macOS)
     let accessibility: Bool
     if prompt {
         // Literal key for kAXTrustedCheckOptionPrompt; the C global is not
@@ -59,9 +64,29 @@ func makeHealthReport(prompt: Bool, probeCaptureService: Bool) async -> HealthRe
         tccAttribution: tccAttributionNote(parent: process.parent),
         recommendedNextAction: action
     )
+    #else
+    let process = ProcessDiagnostics.current()
+    return HealthReport(
+        reportVersion: 1,
+        version: version,
+        executablePath: executablePath(),
+        bundleIdentifier: Bundle.main.bundleIdentifier,
+        process: process,
+        permissions: PermissionDiagnostics(
+            accessibility: PermissionStatus(granted: false, status: "unsupported", requiredFor: "Accessibility is unsupported on Linux"),
+            screenRecording: PermissionStatus(granted: false, status: "unsupported", requiredFor: "Screen Recording is unsupported on Linux")
+        ),
+        captureService: CaptureServiceDiagnostic(status: .skipped, detail: "Screen capture is unsupported on Linux."),
+        daemon: daemonDiagnostics(),
+        telemetry: telemetryDiagnostics(),
+        tccAttribution: "Linux does not use TCC.",
+        recommendedNextAction: "Linux reports unsupported capabilities; use version/help/health_report for diagnostics."
+    )
+    #endif
 }
 
 private func captureServiceDiagnostic(screenRecordingGranted: Bool, probe: Bool) async -> CaptureServiceDiagnostic {
+    #if os(macOS)
     guard screenRecordingGranted else {
         return CaptureServiceDiagnostic(
             status: .skipped,
@@ -89,6 +114,9 @@ private func captureServiceDiagnostic(screenRecordingGranted: Bool, probe: Bool)
             detail: "ScreenCaptureKit did not respond: \(error)"
         )
     }
+    #else
+    return CaptureServiceDiagnostic(status: .skipped, detail: "Screen capture is unsupported on Linux.")
+    #endif
 }
 
 func recommendedNextAction(
@@ -174,6 +202,7 @@ struct ProcessDiagnostics: Codable, Sendable {
     let parent: ProcessIdentity?
 
     static func current() -> ProcessDiagnostics {
+        #if os(macOS)
         let pid = ProcessInfo.processInfo.processIdentifier
         let currentApp = NSRunningApplication.current
         let currentExecutablePath = executablePath()
@@ -186,6 +215,18 @@ struct ProcessDiagnostics: Codable, Sendable {
         )
         let parent = ProcessIdentity(pid: getppid())
         return ProcessDiagnostics(current: current, parent: parent)
+        #else
+        let pid = ProcessInfo.processInfo.processIdentifier
+        let current = ProcessIdentity(
+            pid: pid,
+            name: ProcessInfo.processInfo.processName,
+            bundleIdentifier: Bundle.main.bundleIdentifier,
+            bundlePath: Bundle.main.bundleURL.standardizedFileURL.path,
+            executablePath: executablePath()
+        )
+        let parent = ProcessIdentity(pid: getppid())
+        return ProcessDiagnostics(current: current, parent: parent)
+        #endif
     }
 }
 
@@ -230,6 +271,7 @@ struct ProcessIdentity: Codable, Sendable {
 }
 
 private func processExecutablePath(pid: Int32) -> String? {
+    #if os(macOS)
     var buffer = [CChar](repeating: 0, count: 4096)
     let result = buffer.withUnsafeMutableBufferPointer { pointer in
         proc_pidpath(pid, pointer.baseAddress, UInt32(pointer.count))
@@ -237,6 +279,9 @@ private func processExecutablePath(pid: Int32) -> String? {
     guard result > 0 else { return nil }
     let bytes = buffer.prefix(Int(result)).map { UInt8(bitPattern: $0) }
     return String(decoding: bytes, as: UTF8.self)
+    #else
+    return nil
+    #endif
 }
 
 struct PermissionDiagnostics: Codable, Sendable {
diff --git a/Sources/computer-use-mcp/LinuxStubs.swift b/Sources/computer-use-mcp/LinuxStubs.swift
new file mode 100644
index 0000000..8ec7331
--- /dev/null
+++ b/Sources/computer-use-mcp/LinuxStubs.swift
@@ -0,0 +1,378 @@
+#if os(Linux)
+import Foundation
+#if canImport(FoundationNetworking)
+import FoundationNetworking
+#endif
+import MCP
+
+enum InputTier: String {
+    case accessibilityAction = "tier1-ax-action"
+    case accessibilityAttribute = "tier1-ax-attribute"
+    case perWindow = "tier2-per-window-nsevent"
+    case skyLight = "tier25-skylight-sleventpostto-pid"
+    case perPid = "tier3-cgeventpostto-pid"
+    case globalCursor = "tier4-global-cursor"
+    case pasteboard = "pasteboard"
+    case launchServices = "launchservices"
+    case windowManagement = "ax-window-management"
+}
+
+enum KeyDeliveryMode: String, Equatable {
+    case skyLight = "tier25-skylight-sleventpostto-pid"
+    case perPid = "tier3-cgeventpostto-pid"
+    case globalSessionTap = "tier4-global-session-tap"
+}
+
+enum FallbackReason: String, Equatable, Sendable {
+    case axActionUnsupported = "ax-action-unsupported"
+    case windowNumberUnresolved = "window-number-unresolved"
+    case windowFrameUnresolved = "window-frame-unresolved"
+    case eventBridgeFailed = "event-bridge-failed"
+    case skyLightUnavailable = "skylight-unavailable"
+    case globalCursorRequested = "global-cursor-requested"
+    case noScrollContainerFound = "no-scroll-container-found"
+    case scrollActionUnverified = "scroll-action-unverified"
+    case chainAXPressUnverified = "chain-ax-press-unverified"
+    case chainAXConfirmUnverified = "chain-ax-confirm-unverified"
+    case chainAXOpenUnverified = "chain-ax-open-unverified"
+    case chainAXPickUnverified = "chain-ax-pick-unverified"
+    case chainSelectionRelayUnverified = "chain-selection-relay-unverified"
+    case chainChildActionUnverified = "chain-child-action-unverified"
+    case chainAncestorActionUnverified = "chain-ancestor-action-unverified"
+}
+
+struct DeliveryOutcome: Equatable {
+    let tier: InputTier
+    let fallbackReasons: [FallbackReason]
+
+    init(tier: InputTier, fallbackReasons: [FallbackReason] = []) {
+        self.tier = tier
+        self.fallbackReasons = fallbackReasons
+    }
+}
+
+struct DeliveryContext {
+    let pid: pid_t
+    let windowNumber: CGWindowID?
+    let windowFrame: CGRect?
+    let allowGlobalCursor: Bool
+}
+
+enum MouseButtonKind {
+    case left, right, middle
+    var cgButton: CGMouseButton {
+        switch self {
+        case .left: return .left
+        case .right: return .right
+        case .middle: return .center
+        }
+    }
+    var downType: CGEventType {
+        switch self {
+        case .left: return .leftMouseDown
+        case .right: return .rightMouseDown
+        case .middle: return .otherMouseDown
+        }
+    }
+    var upType: CGEventType {
+        switch self {
+        case .left: return .leftMouseUp
+        case .right: return .rightMouseUp
+        case .middle: return .otherMouseUp
+        }
+    }
+}
+
+struct KeyChord {
+    let keyCode: CGKeyCode
+    let flags: CGEventFlags
+}
+
+enum Keymap {
+    static func parse(_ combo: String) throws -> KeyChord {
+        var tokens = combo.split(separator: "+").map { String($0).trimmingCharacters(in: .whitespaces) }
+        guard let key = tokens.popLast(), !key.isEmpty else {
+            throw ToolError.invalidArguments("Empty key string.")
+        }
+        var flags: CGEventFlags = []
+        for token in tokens {
+            switch token.lowercased() {
+            case "cmd", "command", "super", "meta": flags.insert(.maskCommand)
+            case "ctrl", "control": flags.insert(.maskControl)
+            case "alt", "option": flags.insert(.maskAlternate)
+            case "shift": flags.insert(.maskShift)
+            case "fn": flags.insert(.maskSecondaryFn)
+            default: throw ToolError.invalidArguments("Unknown modifier \"\(token)\".")
+            }
+        }
+        let named: [String: CGKeyCode] = [
+            "return": CGKeyCode(kVK_Return), "enter": CGKeyCode(kVK_Return),
+            "tab": CGKeyCode(kVK_Tab), "escape": CGKeyCode(kVK_Escape),
+            "esc": CGKeyCode(kVK_Escape), "space": CGKeyCode(kVK_Space),
+            "delete": CGKeyCode(kVK_Delete), "up": CGKeyCode(kVK_UpArrow),
+            "down": CGKeyCode(kVK_DownArrow), "left": CGKeyCode(kVK_LeftArrow),
+            "right": CGKeyCode(kVK_RightArrow)
+        ]
+        let code: CGKeyCode
+        if let namedCode = named[key.lowercased()] {
+            code = namedCode
+        } else if key.count == 1, let scalar = key.unicodeScalars.first, scalar.isASCII {
+            code = CGKeyCode(scalar.value)
+            if "!@#$%^&*()_+{}|:\"<>?" .contains(key) {
+                flags.insert(.maskShift)
+            }
+        } else {
+            throw ToolError.invalidArguments("Unknown key \"\(key)\".")
+        }
+        return KeyChord(keyCode: code, flags: flags)
+    }
+    static func wouldInsertText(combo: String, chord: KeyChord) -> Bool {
+        let lower = combo.lowercased()
+        guard !chord.flags.contains(.maskCommand), !chord.flags.contains(.maskControl),
+            !chord.flags.contains(.maskAlternate)
+        else { return false }
+        return lower == "space" || (combo.count == 1 && combo.first?.isLetter == true) || combo == "?"
+    }
+}
+
+enum TextExtraction {
+    struct VisibleText {
+        var markdown: String
+        var range: CFRange
+    }
+
+    static func visibleText(of element: AXUIElement) -> VisibleText? { nil }
+    static func webAreaMarkdown(of element: AXUIElement) -> String? { nil }
+}
+
+func attributedStringToMarkdown(_ attributed: NSAttributedString) -> String { attributed.string }
+
+func perWindowFallbackReasons(context: DeliveryContext, bridgeSucceeded: Bool) -> [FallbackReason] {
+    var reasons: [FallbackReason] = []
+    if context.windowNumber == nil { reasons.append(.windowNumberUnresolved) }
+    if context.windowFrame == nil { reasons.append(.windowFrameUnresolved) }
+    if context.windowNumber != nil, context.windowFrame != nil, !bridgeSucceeded {
+        reasons.append(.eventBridgeFailed)
+    }
+    return reasons
+}
+func isDroppableBackgroundDeliveryTier(_ rawTier: String) -> Bool {
+    rawTier == InputTier.perWindow.rawValue
+        || rawTier == InputTier.skyLight.rawValue
+        || rawTier == InputTier.perPid.rawValue
+        || rawTier == KeyDeliveryMode.skyLight.rawValue
+        || rawTier == KeyDeliveryMode.perPid.rawValue
+}
+
+@discardableResult
+func deliverClick(
+    at point: CGPoint, button: MouseButtonKind, clickCount: Int, context: DeliveryContext,
+    allowGlobalCursor: Bool = false
+) throws -> DeliveryOutcome {
+    throw ToolError.failed("Mouse click delivery is unsupported on Linux.")
+}
+
+@discardableResult
+func deliverScroll(at point: CGPoint, deltaX: Int, deltaY: Int, context: DeliveryContext) throws -> InputTier {
+    throw ToolError.failed("Scroll delivery is unsupported on Linux.")
+}
+
+@discardableResult
+func deliverDrag(from: CGPoint, to: CGPoint, context: DeliveryContext) async throws -> InputTier {
+    throw ToolError.failed("Drag delivery is unsupported on Linux.")
+}
+
+@discardableResult
+func typeUnicodeText(_ text: String, context: DeliveryContext) throws -> InputTier {
+    throw ToolError.failed("Text input is unsupported on Linux.")
+}
+
+func keyDeliveryMode(context: DeliveryContext, targetAppIsActive: Bool) throws -> KeyDeliveryMode {
+    if context.allowGlobalCursor {
+        guard targetAppIsActive else {
+            throw ToolError.failed("Global keyboard delivery requires a foreground target.")
+        }
+        return .globalSessionTap
+    }
+    return .perPid
+}
+
+func deliverKey(_ chord: KeyChord, context: DeliveryContext, targetAppIsActive: Bool) throws -> KeyDeliveryMode {
+    throw ToolError.failed("Keyboard input is unsupported on Linux.")
+}
+
+func syntheticFallbackReasons(context: DeliveryContext, allowGlobalCursor: Bool) -> [FallbackReason] { [] }
+func windowID(for axWindow: AXUIElement) -> CGWindowID? { nil }
+func dragReleasePoint(from: CGPoint, to: CGPoint, aborted: Bool) -> CGPoint { aborted ? from : to }
+func unicodeTypingChunks(_ text: String) -> [[UniChar]] {
+    text.map { Array(String($0).utf16) }
+}
+
+func openAppImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("App launching is unsupported on Linux.")
+}
+func openURLImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("URL opening is unsupported on Linux.")
+}
+func listWindowsImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("Window enumeration is unsupported on Linux.")
+}
+func manageWindowImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("Window management is unsupported on Linux.")
+}
+func clickMenuItemImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("Menu interaction is unsupported on Linux.")
+}
+func readClipboardImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("Clipboard access is unsupported on Linux.")
+}
+func writeClipboardImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("Clipboard access is unsupported on Linux.")
+}
+func clipboardRestoreValue(committed: Bool, previous: String?) -> String? { committed ? nil : previous }
+func waitForImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("Waiting for UI conditions is unsupported on Linux.")
+}
+func typeTextImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("Text entry is unsupported on Linux.")
+}
+func setValueImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("Value editing is unsupported on Linux.")
+}
+func selectTextImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("Text selection is unsupported on Linux.")
+}
+func readTextImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("Text reading is unsupported on Linux.")
+}
+func performSecondaryActionImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("Secondary actions are unsupported on Linux.")
+}
+
+struct PageCoordinateProbe: Equatable {
+    let viewportX: Double
+    let viewportY: Double
+    let contentScreenX: Double
+    let contentScreenY: Double
+    let devicePixelRatio: Double
+    var screenPoint: CGPoint {
+        CGPoint(x: contentScreenX + viewportX, y: contentScreenY + viewportY)
+    }
+}
+struct PageDOMSnapshot: Equatable {
+    let value: String?
+    let text: String?
+    let pageSignature: String?
+    func differs(from other: PageDOMSnapshot?) -> Bool { false }
+}
+struct PageProbe { let coordinate: PageCoordinateProbe; let snapshot: PageDOMSnapshot }
+enum PageAction: String { case click, setText = "set_text" }
+enum PageHostType: String, Equatable { case chromium, safari, electron, wkWebView = "wk_webview", unsupported }
+protocol PageJavaScriptExecuting {
+    func evaluate(_ javascript: String, app: ResolvedApp, window: TargetWindow, cdpPort: Int?, targetURLContains: String?) async throws -> String
+    func insertText(_ text: String, selector: String, app: ResolvedApp, window: TargetWindow, cdpPort: Int?, targetURLContains: String?) async throws
+}
+struct SystemPageJavaScriptExecutor: PageJavaScriptExecuting {
+    func evaluate(_ javascript: String, app: ResolvedApp, window: TargetWindow, cdpPort: Int?, targetURLContains: String?) async throws -> String {
+        throw ToolError.failed("Page JavaScript execution is unsupported on Linux.")
+    }
+    func insertText(_ text: String, selector: String, app: ResolvedApp, window: TargetWindow, cdpPort: Int?, targetURLContains: String?) async throws {}
+}
+
+func pageImpl(_ args: [String: Value]) async throws -> CallTool.Result {
+    throw ToolError.failed("Page interaction is unsupported on Linux.")
+}
+func pageProbe(selector: String, app: ResolvedApp, window: TargetWindow, cdpPort: Int?, targetURLContains: String?) async throws -> PageProbe {
+    throw ToolError.failed("Page interaction is unsupported on Linux.")
+}
+func pageDOMSnapshot(selector: String, app: ResolvedApp, window: TargetWindow, cdpPort: Int?, targetURLContains: String?) async throws -> PageDOMSnapshot {
+    throw ToolError.failed("Page interaction is unsupported on Linux.")
+}
+func parsePageProbe(_ raw: String) throws -> PageProbe {
+    let object = try parsePageJSONObject(raw)
+    guard
+        let viewportX = (object["vx"] as? NSNumber)?.doubleValue,
+        let viewportY = (object["vy"] as? NSNumber)?.doubleValue,
+        let contentScreenX = (object["sx"] as? NSNumber)?.doubleValue,
+        let contentScreenY = (object["sy"] as? NSNumber)?.doubleValue
+    else {
+        throw ToolError.failed("page: JavaScript probe missing numeric coordinates: \(raw)")
+    }
+    let coordinate = PageCoordinateProbe(
+        viewportX: viewportX,
+        viewportY: viewportY,
+        contentScreenX: contentScreenX,
+        contentScreenY: contentScreenY,
+        devicePixelRatio: (object["dpr"] as? NSNumber)?.doubleValue ?? 1
+    )
+    return PageProbe(
+        coordinate: coordinate,
+        snapshot: PageDOMSnapshot(
+            value: object["value"] as? String,
+            text: object["text"] as? String,
+            pageSignature: object["pageSignature"] as? String
+        )
+    )
+}
+func parsePageDOMSnapshot(_ raw: String) throws -> PageDOMSnapshot {
+    let object = try parsePageJSONObject(raw)
+    return PageDOMSnapshot(
+        value: object["value"] as? String,
+        text: object["text"] as? String,
+        pageSignature: object["pageSignature"] as? String
+    )
+}
+private func parsePageJSONObject(_ raw: String) throws -> [String: Any] {
+    let first = try JSONSerialization.jsonObject(with: Data(raw.trimmingCharacters(in: .whitespacesAndNewlines).utf8), options: [.fragmentsAllowed])
+    if let string = first as? String, let nested = try? JSONSerialization.jsonObject(with: Data(string.utf8)), let object = nested as? [String: Any] {
+        return object
+    }
+    guard let object = first as? [String: Any] else {
+        throw ToolError.failed("page: JavaScript returned non-object JSON: \(raw)")
+    }
+    return object
+}
+func pageHostType(for app: ResolvedApp, frameworks: [String]? = nil) -> PageHostType { .unsupported }
+func selectCDPPageTarget(_ targets: [[String: Any]], targetURLContains: String?, port: Int) throws -> [String: Any]? { nil }
+func jsonString(_ value: String) -> String { "\"\(value)\"" }
+
+func openClipboard() {}
+
+private actor LinuxTimeoutGate<T: Sendable> {
+    private var finished = false
+    private var continuation: CheckedContinuation<T, Error>?
+
+    init(_ continuation: CheckedContinuation<T, Error>) {
+        self.continuation = continuation
+    }
+
+    func finish(_ result: Result<T, Error>) {
+        guard !finished, let continuation else { return }
+        finished = true
+        self.continuation = nil
+        continuation.resume(with: result)
+    }
+}
+
+func withTimeout<T: Sendable>(
+    seconds: Double,
+    label: String,
+    operation: @escaping @Sendable () async throws -> T
+) async throws -> T {
+    try await withCheckedThrowingContinuation { continuation in
+        let gate = LinuxTimeoutGate(continuation)
+        Task.detached {
+            do {
+                await gate.finish(.success(try await operation()))
+            } catch {
+                await gate.finish(.failure(error))
+            }
+        }
+        Task.detached {
+            try? await Task.sleep(for: .seconds(seconds))
+            await gate.finish(.failure(ToolError.failed("\(label) timed out after \(Int(seconds))s.")))
+        }
+    }
+}
+
+#endif
diff --git a/Sources/computer-use-mcp/LinuxSupport.swift b/Sources/computer-use-mcp/LinuxSupport.swift
new file mode 100644
index 0000000..a2e37c9
--- /dev/null
+++ b/Sources/computer-use-mcp/LinuxSupport.swift
@@ -0,0 +1,285 @@
+#if os(Linux)
+import Foundation
+import Glibc
+
+struct LinuxPeerCredentials {
+    var pid: pid_t = 0
+    var uid: uid_t = 0
+    var gid: gid_t = 0
+}
+
+typealias CFTypeRef = Any
+typealias CFDictionary = [AnyHashable: Any]
+typealias CFMachPort = OpaquePointer
+typealias CFRunLoopSource = OpaquePointer
+typealias CFRunLoop = OpaquePointer
+typealias CGDirectDisplayID = UInt32
+typealias CGImage = AnyObject
+typealias CFString = String
+typealias CFArray = [Any]
+typealias CFData = Data
+typealias CFBoolean = Bool
+typealias AXValue = AnyObject
+typealias AXUIElementRef = AXUIElement
+typealias CGWindowID = UInt32
+typealias CGKeyCode = UInt16
+typealias UniChar = UInt16
+struct DarwinBoolean {
+    var boolValue: Bool
+    init(_ value: Bool) { boolValue = value }
+}
+typealias CFTimeInterval = Double
+typealias IOPMAssertionID = UInt32
+enum CGError: Int32 { case success = 0 }
+typealias IOPMAssertionLevel = UInt32
+let kIOPMAssertionLevelOn: UInt32 = 255
+let kIOPMAssertionTypePreventUserIdleSystemSleep = "PreventUserIdleSystemSleep"
+let kIOReturnSuccess: Int32 = 0
+func IOPMAssertionCreateWithName(_ type: CFString, _ level: IOPMAssertionLevel, _ name: CFString, _ id: UnsafeMutablePointer<IOPMAssertionID>) -> Int32 { 0 }
+func IOPMAssertionRelease(_ id: IOPMAssertionID) -> Int32 { 0 }
+func CGSessionCopyCurrentDictionary() -> CFDictionary? { [:] }
+
+struct CFRange {
+    init() { location = 0; length = 0 }
+    var location: Int
+    var length: Int
+}
+
+final class AXUIElement: @unchecked Sendable {}
+
+enum AXError: Int32 {
+    case success = 0
+    case attributeUnsupported = -25205
+    case actionUnsupported = -25206
+    case apiDisabled = -25207
+    case cannotComplete = -25208
+    case invalidUIElement = -25209
+    case noValue = -25210
+    case notImplemented = -25211
+}
+enum AXValueType { case cfRange, cgPoint, cgSize }
+
+let kAXChildrenAttribute = "AXChildren"
+let kAXDescriptionAttribute = "AXDescription"
+let kAXHelpAttribute = "AXHelp"
+let kAXParentAttribute = "AXParent"
+let kAXPositionAttribute = "AXPosition"
+let kAXRoleAttribute = "AXRole"
+let kAXSizeAttribute = "AXSize"
+let kAXTitleAttribute = "AXTitle"
+let kAXTitleUIElementAttribute = "AXTitleUIElement"
+let kAXValueAttribute = "AXValue"
+let kAXVisibleCharacterRangeAttribute = "AXVisibleCharacterRange"
+let kAXSubroleAttribute = "AXSubrole"
+let kAXFocusedAttribute = "AXFocused"
+let kAXFocusedWindowAttribute = "AXFocusedWindow"
+let kAXMainWindowAttribute = "AXMainWindow"
+let kAXWindowsAttribute = "AXWindows"
+let kAXEnabledAttribute = "AXEnabled"
+let kAXSelectedAttribute = "AXSelected"
+let kAXSelectedTextAttribute = "AXSelectedText"
+let kAXRoleDescriptionAttribute = "AXRoleDescription"
+let kAXURLAttribute = "AXURL"
+let kAXWindowAttribute = "AXWindow"
+let kAXFocusedUIElementAttribute = "AXFocusedUIElement"
+let kAXSelectedTextRangeAttribute = "AXSelectedTextRange"
+let kAXCloseButtonAttribute = "AXCloseButton"
+let kAXMainAttribute = "AXMain"
+let kAXMenuBarAttribute = "AXMenuBar"
+let kAXMinimizedAttribute = "AXMinimized"
+let kAXRaiseAction = "AXRaise"
+let kCFBooleanFalse = false
+let kAXSecureTextFieldSubrole = "AXSecureTextField"
+let kAXPressAction = "AXPress"
+let kAXAttributedStringForRangeParameterizedAttribute = "AXAttributedStringForRange"
+let kAXStringForRangeParameterizedAttribute = "AXStringForRange"
+let kCFBooleanTrue = true
+
+func AXUIElementCreateApplication(_ pid: pid_t) -> AXUIElement { AXUIElement() }
+func AXUIElementCreateSystemWide() -> AXUIElement { AXUIElement() }
+func AXUIElementGetTypeID() -> Int { 0 }
+func AXValueGetTypeID() -> Int { 0 }
+func AXValueCreate(_ type: AXValueType, _ value: UnsafeRawPointer?) -> AXValue? { nil }
+func AXValueGetValue(_ value: AXValue, _ type: AXValueType, _ ptr: UnsafeMutableRawPointer) -> Bool { false }
+func AXUIElementSetMessagingTimeout(_ element: AXUIElement, _ timeout: Float) {}
+func AXUIElementCopyAttributeValue(
+    _ element: AXUIElement, _ attribute: CFString, _ value: UnsafeMutablePointer<CFTypeRef?>
+) -> AXError { .attributeUnsupported }
+func AXUIElementCopyParameterizedAttributeValue(
+    _ element: AXUIElement, _ attribute: CFString, _ parameter: CFTypeRef,
+    _ value: UnsafeMutablePointer<CFTypeRef?>
+) -> AXError { .attributeUnsupported }
+func AXUIElementCopyAttributeNames(
+    _ element: AXUIElement, _ names: UnsafeMutablePointer<CFArray?>
+) -> AXError { .attributeUnsupported }
+func AXUIElementCopyElementAtPosition(
+    _ element: AXUIElement, _ x: Float, _ y: Float, _ value: UnsafeMutablePointer<AXUIElement?>
+) -> AXError { .attributeUnsupported }
+func AXUIElementCopyActionNames(
+    _ element: AXUIElement, _ names: UnsafeMutablePointer<CFArray?>
+) -> AXError { .attributeUnsupported }
+func AXUIElementPerformAction(_ element: AXUIElement, _ action: CFString) -> AXError { .attributeUnsupported }
+func AXUIElementSetAttributeValue(_ element: AXUIElement, _ attribute: CFString, _ value: CFTypeRef) -> AXError { .attributeUnsupported }
+func AXUIElementIsAttributeSettable(
+    _ element: AXUIElement, _ attribute: CFString, _ settable: UnsafeMutablePointer<DarwinBoolean>
+) -> AXError { .attributeUnsupported }
+func AXIsProcessTrusted() -> Bool { false }
+func AXIsProcessTrustedWithOptions(_ options: CFTypeRef) -> Bool { false }
+func CFGetTypeID(_ value: CFTypeRef) -> Int { 0 }
+func CFEqual(_ lhs: CFTypeRef, _ rhs: CFTypeRef) -> Bool { lhs as AnyObject === rhs as AnyObject }
+func CFAttributedStringGetTypeID() -> Int { 0 }
+func CFBooleanGetTypeID() -> Int { 0 }
+func AXValueGetType(_ value: AXValue) -> Int { 0 }
+
+final class NSRunningApplication: @unchecked Sendable {
+    static let current = NSRunningApplication()
+    var processIdentifier: pid_t { getpid() }
+    var localizedName: String? { nil }
+    var bundleIdentifier: String? { nil }
+    var bundleURL: URL? { nil }
+    var executableURL: URL? { nil }
+    var isTerminated: Bool { false }
+    var isHidden: Bool { false }
+    var isActive: Bool { false }
+    enum ActivationPolicy { case prohibited, regular }
+    var activationPolicy: ActivationPolicy { .regular }
+    init() {}
+    init?(processIdentifier: pid_t) { return nil }
+}
+final class NSWorkspace: @unchecked Sendable {
+    static let shared = NSWorkspace()
+    var runningApplications: [NSRunningApplication] { [] }
+    var frontmostApplication: NSRunningApplication? { nil }
+}
+
+final class NSPasteboard: @unchecked Sendable {
+    static let general = NSPasteboard()
+    func clearContents() {}
+    func setString(_ string: String, forType type: String) -> Bool { false }
+    func string(forType type: String) -> String? { nil }
+}
+
+struct CGEventFlags: OptionSet, Sendable {
+    let rawValue: UInt64
+    init(rawValue: UInt64) { self.rawValue = rawValue }
+    static let maskShift = Self(rawValue: 1 << 17)
+    static let maskControl = Self(rawValue: 1 << 18)
+    static let maskAlternate = Self(rawValue: 1 << 19)
+    static let maskCommand = Self(rawValue: 1 << 20)
+    static let maskSecondaryFn = Self(rawValue: 1 << 23)
+}
+
+enum CGEventType: Int32, Sendable {
+    case leftMouseDown, leftMouseUp, rightMouseDown, rightMouseUp, mouseMoved
+    case leftMouseDragged, rightMouseDragged, otherMouseDown, otherMouseUp, keyDown, keyUp, scrollWheel
+}
+
+enum CGMouseButton: Int32, Sendable { case left, right, center }
+enum CGEventTapLocation: Int32 { case cghidEventTap, cgSessionEventTap }
+enum CGEventTapPlacement: Int32 { case headInsertEventTap }
+enum CGEventTapOptions: Int32 { case listenOnly }
+enum CGEventField: Int32 {
+    case mouseEventClickState = 1
+    case mouseEventWindowUnderMousePointer = 2
+    case mouseEventWindowUnderMousePointerThatCanHandleThisEvent = 3
+    case scrollWheelEventScrollCount = 4
+    case scrollWheelEventFixedPtDeltaAxis1 = 5
+    case scrollWheelEventFixedPtDeltaAxis2 = 6
+    case scrollWheelEventPointDeltaAxis1 = 7
+    case scrollWheelEventPointDeltaAxis2 = 8
+    case scrollWheelEventIsContinuous = 9
+    case scrollWheelEventScrollPhase = 10
+    case scrollWheelEventMomentumPhase = 11
+}
+struct CGScrollPhase: OptionSet, Sendable {
+    let rawValue: UInt32
+    init(rawValue: UInt32) { self.rawValue = rawValue }
+}
+typealias CGMomentumScrollPhase = CGScrollPhase
+final class CGEvent: @unchecked Sendable {
+    var location: CGPoint = .zero
+    var flags: CGEventFlags = []
+    init?(mouseEventSource: CGEventSource?, mouseType: CGEventType, mouseCursorPosition: CGPoint, mouseButton: CGMouseButton) {
+        location = mouseCursorPosition
+    }
+    init?(keyboardEventSource: CGEventSource?, virtualKey: CGKeyCode, keyDown: Bool) {}
+    init?(source: CGEventSource?) {}
+    func setIntegerValueField(_ field: CGEventField, value: Int64) {}
+    func setFlags(_ flags: CGEventFlags) {}
+    func keyboardSetUnicodeString(stringLength: Int, unicodeString: UnsafePointer<UniChar>) {}
+    func keyboardSetUnicodeString(stringLength: Int, unicodeString: UnsafePointer<UniChar>?) {}
+    func getIntegerValueField(_ field: CGEventField) -> Int64 { 0 }
+    func getDoubleValueField(_ field: CGEventField) -> Double { 0 }
+    func keyboardGetUnicodeString(maxStringLength: Int, actualStringLength: inout Int, unicodeString: inout [UniChar]) {}
+    func post(tap: CGEventTapLocation) {}
+    static func tapCreate(
+        tap: CGEventTapLocation, place: CGEventTapPlacement, options: CGEventTapOptions,
+        eventsOfInterest: UInt64, callback: Any, userInfo: UnsafeMutableRawPointer?
+    ) -> OpaquePointer? { nil }
+    static func tapEnable(tap: OpaquePointer, enable: Bool) {}
+    static func sourceCounterForEventType(_ stateID: Int32, eventType: CGEventType) -> UInt64 { 0 }
+}
+final class CGEventSource: @unchecked Sendable {
+    enum StateID { case privateState, combinedSessionState, hidSystemState }
+    init?(stateID: StateID) {}
+    static func secondsSinceLastEventType(_ stateID: StateID, eventType: CGEventType) -> TimeInterval { .infinity }
+}
+
+struct NSEvent {
+    enum EventType { case leftMouseDown, leftMouseUp, rightMouseDown, rightMouseUp, mouseMoved, leftMouseDragged, rightMouseDragged, keyDown, keyUp, scrollWheel }
+    struct ModifierFlags: OptionSet { let rawValue: UInt; init(rawValue: UInt) { self.rawValue = rawValue } }
+    static func mouseEvent(
+        with type: EventType, location: CGPoint, modifierFlags: ModifierFlags, timestamp: TimeInterval,
+        windowNumber: Int, context: Any?, eventNumber: Int, clickCount: Int, pressure: Float
+    ) -> NSEvent? { nil }
+    func cgEvent() -> CGEvent? { nil }
+}
+
+func CGMainDisplayID() -> UInt32 { 0 }
+func CGWindowListCopyWindowInfo(_ option: [CGWindowListOption], _ relativeToWindow: CGWindowID) -> CFArray? { nil }
+let kCGNullWindowID: CGWindowID = 0
+let kCGWindowLayer = "kCGWindowLayer"
+let kCGWindowOwnerPID = "kCGWindowOwnerPID"
+let kCGWindowOwnerName = "kCGWindowOwnerName"
+let kCGWindowBounds = "kCGWindowBounds"
+struct CGWindowListOption: OptionSet {
+    let rawValue: UInt
+    init(rawValue: UInt) { self.rawValue = rawValue }
+    static let optionOnScreenOnly = Self(rawValue: 1 << 0)
+    static let optionIncludingWindow = Self(rawValue: 1 << 1)
+}
+func CGDisplayBounds(_ display: CGDirectDisplayID) -> CGRect { .zero }
+func CGGetActiveDisplayList(_ maxDisplays: UInt32, _ activeDisplays: UnsafeMutablePointer<CGDirectDisplayID>?, _ displayCount: UnsafeMutablePointer<UInt32>) -> CGError { displayCount.pointee = 0; return .success }
+struct CGDisplayMode { let pixelWidth: Int }
+func CGDisplayCopyDisplayMode(_ display: CGDirectDisplayID) -> CGDisplayMode? { nil }
+func CGWarpMouseCursorPosition(_ point: CGPoint) {}
+func IsSecureEventInputEnabled() -> Bool { false }
+let kVK_Delete = 51
+let kVK_ForwardDelete = 117
+let kVK_ANSI_KeypadEnter = 76
+let kVK_Return = 36
+let kVK_Tab = 48
+let kVK_Space = 49
+let kVK_Escape = 53
+let kVK_LeftArrow = 123
+let kVK_RightArrow = 124
+let kVK_DownArrow = 125
+let kVK_UpArrow = 126
+let kVK_Home = 115
+let kVK_End = 119
+let kVK_PageUp = 116
+let kVK_PageDown = 121
+let kVK_F1 = 122
+let kVK_F2 = 120
+let kVK_F3 = 99
+let kVK_F4 = 118
+let kVK_F5 = 96
+let kVK_F6 = 97
+let kVK_F7 = 98
+let kVK_F8 = 100
+let kVK_F9 = 101
+let kVK_F10 = 109
+let kVK_F11 = 103
+let kVK_F12 = 111
+func proc_listallpids(_ buffer: UnsafeMutableRawPointer, _ size: Int32) -> Int32 { 0 }
+#endif
diff --git a/Sources/computer-use-mcp/Overlay/AgentCursor.swift b/Sources/computer-use-mcp/Overlay/AgentCursor.swift
index 968d258..3e115dc 100644
--- a/Sources/computer-use-mcp/Overlay/AgentCursor.swift
+++ b/Sources/computer-use-mcp/Overlay/AgentCursor.swift
@@ -10,8 +10,10 @@
 // The overlay is purely cosmetic; it never moves the real cursor, and a
 // dead/failed helper never blocks or fails the action.
 
-import CoreGraphics
 import Foundation
+#if os(macOS)
+import CoreGraphics
+#endif
 
 actor AgentCursor {
     static let shared = AgentCursor()
diff --git a/Sources/computer-use-mcp/Overlay/OverlayHelper.swift b/Sources/computer-use-mcp/Overlay/OverlayHelper.swift
index 34ec7b4..75804ca 100644
--- a/Sources/computer-use-mcp/Overlay/OverlayHelper.swift
+++ b/Sources/computer-use-mcp/Overlay/OverlayHelper.swift
@@ -1,3 +1,4 @@
+#if os(macOS)
 // `overlay` subcommand — the agent-cursor overlay helper process.
 //
 // The MCP server is a headless async stdio process with no AppKit run loop, so
@@ -20,8 +21,10 @@
 // glyph appears on whichever display contains it (including straddling a
 // boundary mid-glide).
 
+#if os(macOS)
 import AppKit
 import QuartzCore
+#endif
 
 /// Stderr diagnostics, enabled with COMPUTER_USE_MCP_OVERLAY_DEBUG=1. The
 /// helper inherits the server's stderr, so these reach the MCP host's logs.
@@ -29,7 +32,6 @@ func overlayDebug(_ message: @autoclosure () -> String) {
     guard ProcessInfo.processInfo.environment["COMPUTER_USE_MCP_OVERLAY_DEBUG"] == "1" else { return }
     FileHandle.standardError.write(Data("[overlay] \(message())\n".utf8))
 }
-
 @MainActor
 func runOverlay() -> Never {
     // Singleton: the flock is held for the helper's lifetime (the kernel
@@ -50,7 +52,6 @@ func runOverlay() -> Never {
     app.run()
     exit(0)
 }
-
 private func prepareOverlayFifo() {
     let path = overlayFifoPath()
     var status = stat()
@@ -811,3 +812,10 @@ private final class OverlayController: NSObject, NSApplicationDelegate {
         return image.cgImage(forProposedRect: nil, context: nil, hints: nil)
     }
 }
+#else
+import Foundation
+
+func runOverlay() -> Never {
+    fatalError("The agent cursor overlay is unsupported on Linux.")
+}
+#endif
diff --git a/Sources/computer-use-mcp/Skills/Recorder.swift b/Sources/computer-use-mcp/Skills/Recorder.swift
index 00dd867..838b189 100644
--- a/Sources/computer-use-mcp/Skills/Recorder.swift
+++ b/Sources/computer-use-mcp/Skills/Recorder.swift
@@ -13,11 +13,13 @@
 // thread is parked. The compile step (recorded events → skill steps) is a
 // pure function, unit-tested without a tap.
 
+import Foundation
+import MCP
+#if os(macOS)
 import ApplicationServices
 import Carbon.HIToolbox
 import CoreGraphics
-import Foundation
-import MCP
+#endif
 
 /// One observed user action, app-relative. Captured live, compiled at stop.
 enum RecordedEvent: Equatable {
@@ -85,6 +87,7 @@ enum RecorderError: Error, CustomStringConvertible {
     }
 }
 
+#if os(macOS)
 /// Owns the event tap and the live event buffer. A final class (not an actor)
 /// because the CGEventTap C callback needs a stable refcon pointer and runs on
 /// the tap thread; a lock guards the shared buffer.
@@ -295,6 +298,20 @@ final class SkillRecorder: @unchecked Sendable {
         pendingText = ""
     }
 }
+#else
+final class SkillRecorder: @unchecked Sendable {
+    static let shared = SkillRecorder()
+    var isRecording: Bool { false }
+
+    func start(app: ResolvedApp) throws {
+        throw RecorderError.tapCreationFailed
+    }
+
+    func stop() throws -> (app: String, steps: [SkillStep]) {
+        throw RecorderError.notRecording
+    }
+}
+#endif
 
 /// Map a control character produced by keyboardGetUnicodeString to a key name,
 /// or nil when it is ordinary text.
diff --git a/Sources/computer-use-mcp/Tools/ClickTool.swift b/Sources/computer-use-mcp/Tools/ClickTool.swift
index 9f7c9d8..80afe24 100644
--- a/Sources/computer-use-mcp/Tools/ClickTool.swift
+++ b/Sources/computer-use-mcp/Tools/ClickTool.swift
@@ -3,9 +3,11 @@
 // background, no event posted); otherwise it descends the synthetic input
 // ladder (per-window NSEvent → per-pid CGEvent → guarded global cursor).
 
-import ApplicationServices
 import Foundation
 import MCP
+#if os(macOS)
+import ApplicationServices
+#endif
 
 func clickImpl(_ args: [String: Value]) async throws -> CallTool.Result {
     let app = try resolveApp(args.requireString("app"))
diff --git a/Sources/computer-use-mcp/Tools/InputTools.swift b/Sources/computer-use-mcp/Tools/InputTools.swift
index 6058b85..5d81796 100644
--- a/Sources/computer-use-mcp/Tools/InputTools.swift
+++ b/Sources/computer-use-mcp/Tools/InputTools.swift
@@ -1,10 +1,12 @@
 // press_key, scroll, drag — the synthetic-input tools.
 
+import Foundation
+import MCP
+#if os(macOS)
 import AppKit
 import ApplicationServices
 import CoreGraphics
-import Foundation
-import MCP
+#endif
 
 func pressKeyImpl(_ args: [String: Value]) async throws -> CallTool.Result {
     let app = try resolveApp(args.requireString("app"))
@@ -230,7 +232,11 @@ func scrollImpl(_ args: [String: Value]) async throws -> CallTool.Result {
     }
 
     // Tier 2: synthetic wheel at the hit point.
+    #if os(Linux)
+    let tier = try deliverScroll(at: point, deltaX: deltaX, deltaY: deltaY, context: target.deliveryContext)
+    #else
     let tier = deliverScroll(at: point, deltaX: deltaX, deltaY: deltaY, context: target.deliveryContext)
+    #endif
     try? await Task.sleep(for: .milliseconds(80))
 
     if let container, let beforeOffset, let afterOffset = scrollOffsetSignature(container) {
@@ -281,7 +287,11 @@ func dragImpl(_ args: [String: Value]) async throws -> CallTool.Result {
         allowGlobalCursor: false
     )
     await AgentCursor.shared.glide(to: from, targetWindow: context.windowNumber)
+    #if os(Linux)
+    let tier = try await deliverDrag(from: from, to: to, context: context)
+    #else
     let tier = await deliverDrag(from: from, to: to, context: context)
+    #endif
     await AgentCursor.shared.pulse(at: to, targetWindow: context.windowNumber)
     try? await Task.sleep(for: .milliseconds(80))
 
diff --git a/Sources/computer-use-mcp/Tools/PageTool.swift b/Sources/computer-use-mcp/Tools/PageTool.swift
index bd894c5..1be6aaf 100644
--- a/Sources/computer-use-mcp/Tools/PageTool.swift
+++ b/Sources/computer-use-mcp/Tools/PageTool.swift
@@ -1,3 +1,4 @@
+ #if os(macOS)
 // page — CSS-selector-addressed web interaction for browser/webview surfaces.
 //
 // JS-capable hosts (Safari/Chromium and Electron with CDP) get DOM probes and
@@ -5,11 +6,16 @@
 // downgraded when only AX evidence exists: a successful AX echo is not DOM
 // proof.
 
+import Foundation
+#if os(Linux)
+import FoundationNetworking
+#endif
+import MCP
+#if os(macOS)
 import AppKit
 import ApplicationServices
 import CoreGraphics
-import Foundation
-import MCP
+#endif
 
 enum PageAction: String {
     case click
@@ -975,3 +981,4 @@ func jsonString(_ value: String) -> String {
 private func appleScriptString(_ value: String) -> String {
     "\"" + value.replacingOccurrences(of: "\\", with: "\\\\").replacingOccurrences(of: "\"", with: "\\\"") + "\""
 }
+#endif
diff --git a/Sources/computer-use-mcp/Tools/Perception.swift b/Sources/computer-use-mcp/Tools/Perception.swift
index 8faccec..cec8812 100644
--- a/Sources/computer-use-mcp/Tools/Perception.swift
+++ b/Sources/computer-use-mcp/Tools/Perception.swift
@@ -1,9 +1,11 @@
 // Perception: list_apps and get_app_state, plus the shared fresh-state
 // result that every interaction tool returns after acting.
 
-import ApplicationServices
 import Foundation
 import MCP
+#if os(macOS)
+import ApplicationServices
+#endif
 
 func listAppsImpl(_ args: [String: Value]) async throws -> CallTool.Result {
     .text(runningAppsDescription())
diff --git a/Sources/computer-use-mcp/Tools/SystemTools.swift b/Sources/computer-use-mcp/Tools/SystemTools.swift
index 4d372a5..e4d4a5b 100644
--- a/Sources/computer-use-mcp/Tools/SystemTools.swift
+++ b/Sources/computer-use-mcp/Tools/SystemTools.swift
@@ -1,10 +1,13 @@
+ #if os(macOS)
 // System-level tools: open_app, open_url, list_windows, manage_window,
 // click_menu_item, and clipboard access.
 
-import AppKit
-import ApplicationServices
 import Foundation
 import MCP
+#if os(macOS)
+import AppKit
+import ApplicationServices
+#endif
 
 // MARK: - open_app
 
@@ -583,3 +586,4 @@ private func elementExists(
     }
     return false
 }
+#endif
diff --git a/Sources/computer-use-mcp/Tools/TextTools.swift b/Sources/computer-use-mcp/Tools/TextTools.swift
index 4a14632..be13fb7 100644
--- a/Sources/computer-use-mcp/Tools/TextTools.swift
+++ b/Sources/computer-use-mcp/Tools/TextTools.swift
@@ -1,9 +1,12 @@
+ #if os(macOS)
 // Text and value manipulation via the accessibility API: type_text,
 // set_value, select_text, perform_secondary_action.
 
-import ApplicationServices
 import Foundation
 import MCP
+#if os(macOS)
+import ApplicationServices
+#endif
 
 // MARK: - type_text
 
@@ -415,3 +418,4 @@ func performSecondaryActionImpl(_ args: [String: Value]) async throws -> CallToo
         verifier: verifier
     )
 }
+#endif
diff --git a/Sources/computer-use-mcp/main.swift b/Sources/computer-use-mcp/main.swift
index 50359ac..40bc6f1 100644
--- a/Sources/computer-use-mcp/main.swift
+++ b/Sources/computer-use-mcp/main.swift
@@ -1,7 +1,9 @@
 // computer-use-mcp — entry point.
 
-import CoreGraphics
 import Foundation
+#if os(macOS)
+import CoreGraphics
+#endif
 
 // Establish the window-server connection on the main thread before any
 // CoreGraphics/ScreenCaptureKit call runs on a worker thread; without this,
diff --git a/Tests/ComputerUseMCPTests/ActionOutcomeTests.swift b/Tests/ComputerUseMCPTests/ActionOutcomeTests.swift
index 7aebf61..1091ed5 100644
--- a/Tests/ComputerUseMCPTests/ActionOutcomeTests.swift
+++ b/Tests/ComputerUseMCPTests/ActionOutcomeTests.swift
@@ -1,4 +1,7 @@
+#if os(macOS)
 import CoreGraphics
+#endif
+import Foundation
 import MCP
 import Testing
 
diff --git a/Tests/ComputerUseMCPTests/CoordinateTests.swift b/Tests/ComputerUseMCPTests/CoordinateTests.swift
index a41f4ea..044ee7d 100644
--- a/Tests/ComputerUseMCPTests/CoordinateTests.swift
+++ b/Tests/ComputerUseMCPTests/CoordinateTests.swift
@@ -1,4 +1,6 @@
+ #if os(macOS)
 import CoreGraphics
+#endif
 import Foundation
 import Testing
 
diff --git a/Tests/ComputerUseMCPTests/DeliveryFallbackTests.swift b/Tests/ComputerUseMCPTests/DeliveryFallbackTests.swift
index 0701d1c..0aace8c 100644
--- a/Tests/ComputerUseMCPTests/DeliveryFallbackTests.swift
+++ b/Tests/ComputerUseMCPTests/DeliveryFallbackTests.swift
@@ -1,4 +1,7 @@
+#if os(macOS)
 import CoreGraphics
+#endif
+import Foundation
 import Testing
 
 @testable import computer_use_mcp
diff --git a/Tests/ComputerUseMCPTests/DragGuardTests.swift b/Tests/ComputerUseMCPTests/DragGuardTests.swift
index 6f7e53b..5d671f6 100644
--- a/Tests/ComputerUseMCPTests/DragGuardTests.swift
+++ b/Tests/ComputerUseMCPTests/DragGuardTests.swift
@@ -1,4 +1,7 @@
+#if os(macOS)
 import CoreGraphics
+#endif
+import Foundation
 import Testing
 
 @testable import computer_use_mcp
diff --git a/Tests/ComputerUseMCPTests/FocusTelemetryTests.swift b/Tests/ComputerUseMCPTests/FocusTelemetryTests.swift
index 3c244df..beba427 100644
--- a/Tests/ComputerUseMCPTests/FocusTelemetryTests.swift
+++ b/Tests/ComputerUseMCPTests/FocusTelemetryTests.swift
@@ -1,3 +1,4 @@
+ #if os(macOS)
 import MCP
 import Testing
 
@@ -189,3 +190,4 @@ private func invalidArgumentMessage(_ body: () throws -> Void) -> String {
     }
     return ""
 }
+#endif
diff --git a/Tests/ComputerUseMCPTests/GenerationLifecycleTests.swift b/Tests/ComputerUseMCPTests/GenerationLifecycleTests.swift
index 77bf877..6589ded 100644
--- a/Tests/ComputerUseMCPTests/GenerationLifecycleTests.swift
+++ b/Tests/ComputerUseMCPTests/GenerationLifecycleTests.swift
@@ -1,4 +1,6 @@
+ #if os(macOS)
 import CoreGraphics
+#endif
 import Foundation
 import Testing
 
diff --git a/Tests/ComputerUseMCPTests/KeyDeliveryTests.swift b/Tests/ComputerUseMCPTests/KeyDeliveryTests.swift
index 3680099..6be3290 100644
--- a/Tests/ComputerUseMCPTests/KeyDeliveryTests.swift
+++ b/Tests/ComputerUseMCPTests/KeyDeliveryTests.swift
@@ -1,4 +1,7 @@
+#if os(macOS)
 import CoreGraphics
+#endif
+import Foundation
 import Testing
 
 @testable import computer_use_mcp
diff --git a/Tests/ComputerUseMCPTests/KeymapTests.swift b/Tests/ComputerUseMCPTests/KeymapTests.swift
index 85df3d2..7fd6bad 100644
--- a/Tests/ComputerUseMCPTests/KeymapTests.swift
+++ b/Tests/ComputerUseMCPTests/KeymapTests.swift
@@ -1,4 +1,7 @@
+#if os(macOS)
 import Carbon.HIToolbox
+#endif
+import Foundation
 import Testing
 
 @testable import computer_use_mcp
diff --git a/Tests/ComputerUseMCPTests/PageToolTests.swift b/Tests/ComputerUseMCPTests/PageToolTests.swift
index 3a23220..f5cc9b8 100644
--- a/Tests/ComputerUseMCPTests/PageToolTests.swift
+++ b/Tests/ComputerUseMCPTests/PageToolTests.swift
@@ -1,5 +1,7 @@
+#if os(macOS)
 import ApplicationServices
 import CoreGraphics
+import Foundation
 import Testing
 
 @testable import computer_use_mcp
@@ -182,3 +184,4 @@ private struct MockPageJavaScriptExecutor: PageJavaScriptExecuting {
         ResolvedApp(pid: 123, name: "TestApp", bundleIdentifier: bundleIdentifier)
     }
 }
+#endif
diff --git a/Tests/ComputerUseMCPTests/SafetyPolicyTests.swift b/Tests/ComputerUseMCPTests/SafetyPolicyTests.swift
index cfc49a0..9ffc74f 100644
--- a/Tests/ComputerUseMCPTests/SafetyPolicyTests.swift
+++ b/Tests/ComputerUseMCPTests/SafetyPolicyTests.swift
@@ -1,4 +1,6 @@
+#if os(macOS)
 import ApplicationServices
+#endif
 import Foundation
 import Testing
 
diff --git a/Tests/ComputerUseMCPTests/SkyLightInputTests.swift b/Tests/ComputerUseMCPTests/SkyLightInputTests.swift
index 1f78fab..114014a 100644
--- a/Tests/ComputerUseMCPTests/SkyLightInputTests.swift
+++ b/Tests/ComputerUseMCPTests/SkyLightInputTests.swift
@@ -1,5 +1,11 @@
+ #if os(macOS)
+#if os(macOS)
 import CoreGraphics
+#endif
+#if os(macOS)
 import Darwin
+#endif
+import Foundation
 import Testing
 
 @testable import computer_use_mcp
@@ -200,8 +206,9 @@ private final class RecordingSkyLightPosting: SkyLightEventPosting {
         return windowLocationResult
     }
 
-    func setIntegerField(_ event: CGEvent, field: Int, value: Int64) -> Bool {
-        integerFields.append(field)
-        return integerFieldResult
+func setIntegerField(_ event: CGEvent, field: Int, value: Int64) -> Bool {
+    integerFields.append(field)
+    return integerFieldResult
     }
 }
+#endif
diff --git a/Tests/ComputerUseMCPTests/TextExtractionTests.swift b/Tests/ComputerUseMCPTests/TextExtractionTests.swift
index 1e4a308..8418274 100644
--- a/Tests/ComputerUseMCPTests/TextExtractionTests.swift
+++ b/Tests/ComputerUseMCPTests/TextExtractionTests.swift
@@ -1,5 +1,8 @@
-import AppKit
+ #if os(macOS)
 import Foundation
+#if os(macOS)
+import AppKit
+#endif
 import Testing
 
 @testable import computer_use_mcp
@@ -126,3 +129,4 @@ import Testing
         #expect(runStyle(from: [:]) == RunStyle())
     }
 }
+#endif
diff --git a/Tests/ComputerUseMCPTests/TreeBuilderTests.swift b/Tests/ComputerUseMCPTests/TreeBuilderTests.swift
index 7c876a2..6cfa073 100644
--- a/Tests/ComputerUseMCPTests/TreeBuilderTests.swift
+++ b/Tests/ComputerUseMCPTests/TreeBuilderTests.swift
@@ -1,4 +1,7 @@
+#if os(macOS)
 import CoreGraphics
+#endif
+import Foundation
 import Testing
 
 @testable import computer_use_mcp
diff --git a/Tests/ComputerUseMCPTests/WindowMotionTests.swift b/Tests/ComputerUseMCPTests/WindowMotionTests.swift
index 2917183..785a24a 100644
--- a/Tests/ComputerUseMCPTests/WindowMotionTests.swift
+++ b/Tests/ComputerUseMCPTests/WindowMotionTests.swift
@@ -1,4 +1,7 @@
+#if os(macOS)
 import CoreGraphics
+#endif
+import Foundation
 import Testing
 
 @testable import computer_use_mcp