diff --git a/hands/Sources/byre-hands/Act.swift b/hands/Sources/byre-hands/Act.swift
index 10ff96a..7468d11 100644
--- a/hands/Sources/byre-hands/Act.swift
+++ b/hands/Sources/byre-hands/Act.swift
@@ -56,14 +56,14 @@ func runStep(_ step: [String: Any], _ id: Int, _ w: AXUIElement, _ table: RefTab
     for (k, right, count) in [("click", false, 1), ("double_click", false, 2), ("right_click", true, 1)] {
         if step[k] != nil {
             let p = try point(step[k], info, table)
-            await click(p, right: right, count: count)
+            try await click(p, right: right, count: count)
             return "\(k) at screen \(Int(p.x)),\(Int(p.y))"
         }
     }
     if step["drag"] != nil {
         let from = try point(step["drag"], info, table)
         let to = try point(step["to"], info, table)
-        await drag(from, to)
+        try await drag(from, to)
         return "dragged"
     }
     if step["scroll"] != nil {
@@ -77,7 +77,7 @@ func runStep(_ step: [String: Any], _ id: Int, _ w: AXUIElement, _ table: RefTab
         return "scrolled"
     }
     if let s = step.string("type") {
-        await type(s)
+        try await type(s)
         return "typed \(s.count) characters"
     }
     if let k = step.string("key") {
@@ -85,7 +85,7 @@ func runStep(_ step: [String: Any], _ id: Int, _ w: AXUIElement, _ table: RefTab
         return "key \(k)"
     }
     if let ms = try step.ms("wait") {
-        await pause(ms)
+        try await pause(ms)
         return "waited \(ms)ms"
     }
     throw ToolError("unknown step \(step.keys.sorted())")
@@ -93,11 +93,11 @@ func runStep(_ step: [String: Any], _ id: Int, _ w: AXUIElement, _ table: RefTab
 
 func waitFor(_ args: [String: Any], acted: Bool, _ present: (String) async throws -> Bool) async throws -> String? {
     let wait = try args.ms("wait_ms")
-    let timeout = Double(try args.ms("timeout_ms") ?? 10000) / 1000
+    let timeout = Double(try args.ms("wait_timeout_ms") ?? 10000) / 1000
     if let wait {
-        await pause(wait)
+        try await pause(wait)
     } else if acted {
-        await pause(300)
+        try await pause(300)
     }
     guard let needle = args.string("wait_for") else {
         return nil
@@ -110,16 +110,17 @@ func waitFor(_ args: [String: Any], acted: Bool, _ present: (String) async throw
         if Date().timeIntervalSince(start) > timeout {
             return String(format: "gave up waiting for %@ after %.1fs", needle.debugDescription, timeout)
         }
-        await pause(200)
+        try await pause(200)
     }
 }
 
 func runSteps(_ steps: [[String: Any]], _ id: Int, _ w: AXUIElement, _ table: RefTable) async throws -> [String] {
     var log: [String] = []
     for (i, step) in steps.enumerated() {
+        try Task.checkCancellation()
         do {
             log.append("\(i + 1). " + (try await runStep(step, id, w, table)))
-            await pause(50)
+            try await pause(50)
         } catch let e as ToolError {
             log.append("\(i + 1). " + e.message + "; stopped here")
             break
diff --git a/hands/Sources/byre-hands/Browser.swift b/hands/Sources/byre-hands/Browser.swift
index c18a279..9b4a657 100644
--- a/hands/Sources/byre-hands/Browser.swift
+++ b/hands/Sources/byre-hands/Browser.swift
@@ -65,12 +65,12 @@ func tabs() throws -> String {
 
 func waitLoaded(_ t: TabTarget, timeout: Double) async throws -> String {
     let start = Date()
-    await pause(300)
+    try await pause(300)
     while Date().timeIntervalSince(start) < timeout {
         if (try? js("document.readyState", t)) == "complete" {
             return String(format: "loaded after %.1fs", Date().timeIntervalSince(start))
         }
-        await pause(200)
+        try await pause(200)
     }
     return String(format: "still loading after %.1fs", timeout)
 }
@@ -97,7 +97,7 @@ func browserTool(_ args: [String: Any]) async throws -> [Content] {
         } else {
             _ = try osa("tell application \"Orion\" to set URL of \(target.spec) to \(quote(url))")
         }
-        log.append(try await waitLoaded(target, timeout: Double(try args.ms("timeout_ms") ?? 15000) / 1000))
+        log.append(try await waitLoaded(target, timeout: Double(try args.ms("wait_timeout_ms") ?? 15000) / 1000))
         log.append(try js("document.title + ' | ' + location.href", target))
     case "js":
         log.append(try js(try args.require("code", args.string), target))
@@ -125,7 +125,7 @@ func browserTool(_ args: [String: Any]) async throws -> [Content] {
         if let tab = target.tab {
             _ = try osa("tell application \"Orion\" to set current tab of window \(win) to tab \(tab) of window \(win)")
             log.append("selected tab \(tab) to capture it")
-            await pause(300)
+            try await pause(300)
         }
         let id = try orionWindow(win)
         let shot = try await capture(window: id, display: nil, crop: args.dict("crop"), maxEdge: args.double("max_edge") ?? 1568)
diff --git a/hands/Sources/byre-hands/Chrome.swift b/hands/Sources/byre-hands/Chrome.swift
index 80c58c4..bb1082f 100644
--- a/hands/Sources/byre-hands/Chrome.swift
+++ b/hands/Sources/byre-hands/Chrome.swift
@@ -153,6 +153,7 @@ final class Chrome: @unchecked Sendable {
     }
 
     func send(_ method: String, _ params: [String: Any] = [:], session: String? = nil, timeout: Int = 30) async throws -> [String: Any] {
+        try Task.checkCancellation()
         let id = lock.withLock {
             next += 1
             return next
@@ -180,7 +181,7 @@ final class Chrome: @unchecked Sendable {
                 }
             }
             Task {
-                await pause(timeout * 1000)
+                try? await pause(timeout * 1000)
                 resolve(id, .failure(ToolError("\(method) got no answer from Chrome in \(timeout)s")))
             }
         }
@@ -413,7 +414,7 @@ func openChrome() async throws -> (Chrome, String) {
         if let chrome = await chromeFromProfile() {
             return (chrome, "started Chrome with byre's profile\n")
         }
-        await pause(200)
+        try await pause(200)
     }
     throw ToolError("Chrome's debugger for byre's profile didn't answer within 15s; quit any already-running byre-profile Chrome once and retry")
 }
@@ -528,7 +529,7 @@ func traceStop(_ c: Chrome, _ t: TabState, _ target: String) async throws -> Str
         if Date().timeIntervalSince(start) > 60 {
             throw ToolError("Chrome didn't finish the trace within 60s")
         }
-        await pause(100)
+        try await pause(100)
         stream = c.lock.withLock { t.traceStream }
     }
     var data = Data()
@@ -686,14 +687,14 @@ func chromeTool(_ args: [String: Any]) async throws -> [Content] {
         if let err = r.string("errorText") {
             throw ToolError("navigating to \(url) failed: \(err)")
         }
-        let timeout = Double(try args.ms("timeout_ms") ?? 15000) / 1000
+        let timeout = Double(try args.ms("wait_timeout_ms") ?? 15000) / 1000
         let start = Date()
-        await pause(300)
+        try await pause(300)
         var loaded = false
         while !loaded, Date().timeIntervalSince(start) < timeout {
             loaded = (try? await evaluate(c, t, "document.readyState")) == "complete"
             if !loaded {
-                await pause(200)
+                try await pause(200)
             }
         }
         log.append(String(format: loaded ? "loaded after %.1fs" : "still loading after %.1fs", Date().timeIntervalSince(start)))
diff --git a/hands/Sources/byre-hands/Input.swift b/hands/Sources/byre-hands/Input.swift
index 9c6ee0f..a86168a 100644
--- a/hands/Sources/byre-hands/Input.swift
+++ b/hands/Sources/byre-hands/Input.swift
@@ -18,8 +18,8 @@ let modifierFlags: [String: CGEventFlags] = [
     "fn": .maskSecondaryFn,
 ]
 
-func pause(_ ms: Int) async {
-    try? await Task.sleep(nanoseconds: UInt64(ms) * 1_000_000)
+func pause(_ ms: Int) async throws {
+    try await Task.sleep(nanoseconds: UInt64(ms) * 1_000_000)
 }
 
 let shifted: [Character: String] = [
@@ -56,7 +56,12 @@ func lockInput() async throws -> Int32 {
             close(fd)
             throw ToolError("another agent has been driving this Mac's apps for 30s, so nothing ran; try again")
         }
-        await pause(100)
+        do {
+            try await pause(100)
+        } catch {
+            close(fd)
+            throw error
+        }
     }
     return fd
 }
@@ -82,7 +87,7 @@ func focusWindow(_ id: Int, _ w: AXUIElement) async throws -> WindowInfo {
     }
     NSRunningApplication(processIdentifier: info.pid)?.activate()
     AXUIElementPerformAction(w, kAXRaiseAction as CFString)
-    await pause(150)
+    try await pause(150)
     let now = try window(id)
     if try !isFront(now) {
         throw ToolError("could not bring window \(id) to the front (\(NSWorkspace.shared.frontmostApplication?.localizedName ?? "nothing") is frontmost), so no input was sent")
@@ -90,32 +95,34 @@ func focusWindow(_ id: Int, _ w: AXUIElement) async throws -> WindowInfo {
     return now
 }
 
-func click(_ p: CGPoint, right: Bool, count: Int) async {
+func click(_ p: CGPoint, right: Bool, count: Int) async throws {
     let (down, up): (CGEventType, CGEventType) = right ? (.rightMouseDown, .rightMouseUp) : (.leftMouseDown, .leftMouseUp)
     let button: CGMouseButton = right ? .right : .left
     post(CGEvent(mouseEventSource: nil, mouseType: .mouseMoved, mouseCursorPosition: p, mouseButton: button))
-    await pause(30)
+    try await pause(30)
     for i in 1...max(1, count) {
         for t in [down, up] {
             let e = CGEvent(mouseEventSource: nil, mouseType: t, mouseCursorPosition: p, mouseButton: button)
             e?.setIntegerValueField(.mouseEventClickState, value: Int64(i))
             post(e)
         }
-        await pause(30)
+        try await pause(30)
     }
 }
 
-func drag(_ from: CGPoint, _ to: CGPoint) async {
+func drag(_ from: CGPoint, _ to: CGPoint) async throws {
     post(CGEvent(mouseEventSource: nil, mouseType: .mouseMoved, mouseCursorPosition: from, mouseButton: .left))
     post(CGEvent(mouseEventSource: nil, mouseType: .leftMouseDown, mouseCursorPosition: from, mouseButton: .left))
-    await pause(50)
+    defer {
+        post(CGEvent(mouseEventSource: nil, mouseType: .leftMouseUp, mouseCursorPosition: to, mouseButton: .left))
+    }
+    try await pause(50)
     for i in 1...20 {
         let f = CGFloat(i) / 20
         let p = CGPoint(x: from.x + (to.x - from.x) * f, y: from.y + (to.y - from.y) * f)
         post(CGEvent(mouseEventSource: nil, mouseType: .leftMouseDragged, mouseCursorPosition: p, mouseButton: .left))
-        await pause(10)
+        try await pause(10)
     }
-    post(CGEvent(mouseEventSource: nil, mouseType: .leftMouseUp, mouseCursorPosition: to, mouseButton: .left))
 }
 
 func scroll(_ p: CGPoint, dx: Int32, dy: Int32) {
@@ -123,7 +130,7 @@ func scroll(_ p: CGPoint, dx: Int32, dy: Int32) {
     post(CGEvent(scrollWheelEvent2Source: nil, units: .line, wheelCount: 2, wheel1: dy, wheel2: dx, wheel3: 0))
 }
 
-func type(_ s: String) async {
+func type(_ s: String) async throws {
     for ch in s {
         for down in [true, false] {
             if let (code, flags) = keystroke(ch) {
@@ -137,7 +144,7 @@ func type(_ s: String) async {
             e?.keyboardSetUnicodeString(stringLength: units.count, unicodeString: units)
             post(e)
         }
-        await pause(15)
+        try await pause(15)
     }
 }
 
diff --git a/hands/Sources/byre-hands/Server.swift b/hands/Sources/byre-hands/Server.swift
index 0f088dd..b225400 100644
--- a/hands/Sources/byre-hands/Server.swift
+++ b/hands/Sources/byre-hands/Server.swift
@@ -30,6 +30,31 @@ struct Tool {
 }
 
 let stdoutLock = NSLock()
+let maxTimeoutMs = 600_000
+
+final class Once: @unchecked Sendable {
+    private let lock = NSLock()
+    private var done = false
+
+    func run(_ body: () -> Void) {
+        let first = lock.withLock {
+            defer { done = true }
+            return !done
+        }
+        if first {
+            body()
+        }
+    }
+}
+
+func withTimeout(_ schema: String) -> Any {
+    var s = try! JSONSerialization.jsonObject(with: Data(schema.utf8)) as! [String: Any]
+    var props = s["properties"] as? [String: Any] ?? [:]
+    props["timeout_ms"] = ["type": "integer", "description": "Give up on the call after this long (at most \(maxTimeoutMs))."]
+    s["properties"] = props
+    s["required"] = (s["required"] as? [String] ?? []) + ["timeout_ms"]
+    return s
+}
 
 let mediaDir: String? = {
     let args = CommandLine.arguments
@@ -84,7 +109,7 @@ struct Server {
             resp["result"] = [:] as [String: Any]
         case "tools/list":
             resp["result"] = ["tools": tools.map { t in
-                ["name": t.name, "description": t.description, "inputSchema": try! JSONSerialization.jsonObject(with: Data(t.schema.utf8))]
+                ["name": t.name, "description": t.description, "inputSchema": withTimeout(t.schema)]
             }]
         case "tools/call":
             resp["result"] = await call(params)
@@ -104,8 +129,28 @@ struct Server {
         guard let tool = tools.first(where: { $0.name == name }) else {
             return ["content": [Content.text("unknown tool: \(name)").json], "isError": true]
         }
+        guard let ms = args.int("timeout_ms"), ms > 0, ms <= maxTimeoutMs else {
+            return ["content": [Content.text("timeout_ms is required, between 1 and \(maxTimeoutMs)").json], "isError": true]
+        }
         do {
-            let content = try await withDisplayAwake { try await tool.run(args) }
+            let content = try await withCheckedThrowingContinuation { (c: CheckedContinuation<[Content], Error>) in
+                let once = Once()
+                let work = Task {
+                    do {
+                        let content = try await withDisplayAwake { try await tool.run(args) }
+                        once.run { c.resume(returning: content) }
+                    } catch {
+                        once.run { c.resume(throwing: error) }
+                    }
+                }
+                Task {
+                    try? await Task.sleep(for: .milliseconds(ms))
+                    once.run {
+                        work.cancel()
+                        c.resume(throwing: ToolError("\(name) gave no result within \(ms)ms"))
+                    }
+                }
+            }
             return ["content": content.map { $0.json }]
         } catch let e as ToolError {
             return ["content": [Content.text(e.message).json], "isError": true]
diff --git a/hands/Sources/byre-hands/Tools.swift b/hands/Sources/byre-hands/Tools.swift
index acd09b8..edf114e 100644
--- a/hands/Sources/byre-hands/Tools.swift
+++ b/hands/Sources/byre-hands/Tools.swift
@@ -7,7 +7,7 @@ let treeProps = """
 
 let thenProps = """
     "wait_ms": {"type": "integer", "description": "Wait this long after the steps, before wait_for, tree and capture (default 300 when there were steps)."},
-    "timeout_ms": {"type": "integer", "description": "How long wait_for waits before giving up (default 10000). Giving up is reported, not an error."},
+    "wait_timeout_ms": {"type": "integer", "description": "How long wait_for waits before giving up (default 10000). Giving up is reported, not an error."},
     "capture": {"type": "boolean", "description": "Finish with a capture of the window."},
     "crop": {"type": "object", "description": "Capture only this rectangle, in window points.", "properties": {"x": {"type": "number"}, "y": {"type": "number"}, "width": {"type": "number"}, "height": {"type": "number"}}},
     "max_edge": {"type": "number", "description": "Longest edge of the captured image in pixels, 16 to 8192 (default 1568, which is as much as you can see; captures are never scaled up)."}
@@ -121,7 +121,7 @@ let tools: [Tool] = [
             "params": {"type": "object", "description": "For cdp: the method's parameters."},
             "wait_for": {"type": "string", "description": "Then wait until this text (case-insensitive) is in the tab's title or page text, polling every 200ms."},
             "wait_ms": {"type": "integer", "description": "Wait this long after the op, before wait_for and capture."},
-            "timeout_ms": {"type": "integer", "description": "How long navigate waits for the load (default 15000) and wait_for waits (default 10000). Giving up is reported, not an error."},
+            "wait_timeout_ms": {"type": "integer", "description": "How long navigate waits for the load (default 15000) and wait_for waits (default 10000). Giving up is reported, not an error."},
             "capture": {"type": "boolean", "description": "Finish with a screenshot of the tab's page."},
             "max_edge": {"type": "number", "description": "Longest edge of the screenshot in pixels, 16 to 8192 (default 1568, which is as much as you can see)."},
             "save": {"type": "boolean", "description": "With capture, also save the screenshot as a PNG in the task's media folder; the reply gives its path, which a Markdown image in your final message can show."}
diff --git a/internal/agents/bash.go b/internal/agents/bash.go
index fadceed..ccf372a 100644
--- a/internal/agents/bash.go
+++ b/internal/agents/bash.go
@@ -17,22 +17,14 @@ import (
 const bashKeep = 64 << 10
 
 type bashArgs struct {
-	Command   string `json:"command"`
-	TimeoutMs *int   `json:"timeout_ms"`
+	Command string `json:"command"`
 }
 
-func (a bashArgs) timeout() (time.Duration, error) {
+func (a bashArgs) check() error {
 	if strings.TrimSpace(a.Command) == "" {
-		return 0, errors.New("command is empty")
+		return errors.New("command is empty")
 	}
-	timeout := defaultBashTimeout
-	if a.TimeoutMs != nil {
-		timeout = time.Duration(*a.TimeoutMs) * time.Millisecond
-	}
-	if timeout <= 0 || timeout > maxBashTimeout {
-		return 0, fmt.Errorf("timeout_ms must be between 1 and %d", maxBashTimeout.Milliseconds())
-	}
-	return timeout, nil
+	return nil
 }
 
 func (m *Manager) bashTool(l *live) mcp.Tool {
@@ -45,7 +37,7 @@ func (m *Manager) bashTool(l *live) mcp.Tool {
 			"type": "object",
 			"properties": {
 				"command": {"type": "string"},
-				"timeout_ms": {"type": "integer", "description": "Kill the command after this long (default 120000, at most 600000)."}
+				"timeout_ms": {"type": "integer", "description": "Kill the command after this long (at most 600000)."}
 			},
 			"required": ["command"]
 		}`),
@@ -61,7 +53,7 @@ func (m *Manager) bash(ctx context.Context, l *live, raw json.RawMessage) (strin
 	if err != nil {
 		return "", fmt.Errorf("malformed bash call: %w", err)
 	}
-	timeout, err := args.timeout()
+	err = args.check()
 	if err != nil {
 		return "", err
 	}
@@ -70,9 +62,7 @@ func (m *Manager) bash(ctx context.Context, l *live, raw json.RawMessage) (strin
 		return "", errors.New("SHELL is not set in byre's environment")
 	}
 
-	cctx, cancel := context.WithTimeout(ctx, timeout)
-	defer cancel()
-	cmd := procgroup.CommandContext(cctx, shell, "-l", "-c", args.Command)
+	cmd := procgroup.CommandContext(ctx, shell, "-l", "-c", args.Command)
 	cmd.Dir = l.dir
 	cmd.WaitDelay = 5 * time.Second
 	out := &tailWriter{}
@@ -83,10 +73,10 @@ func (m *Manager) bash(ctx context.Context, l *live, raw json.RawMessage) (strin
 	status := "exit status 0"
 	exit := &exec.ExitError{}
 	switch {
+	case errors.Is(ctx.Err(), context.DeadlineExceeded):
+		status = fmt.Sprintf("killed after %s", mcp.Timeout(ctx))
 	case ctx.Err() != nil:
 		return "", ctx.Err()
-	case cctx.Err() != nil:
-		status = fmt.Sprintf("killed after %s", timeout)
 	case errors.As(err, &exit):
 		status = exit.ProcessState.String()
 	case errors.Is(err, exec.ErrWaitDelay):
diff --git a/internal/agents/clients.go b/internal/agents/clients.go
index beeea23..ba610b8 100644
--- a/internal/agents/clients.go
+++ b/internal/agents/clients.go
@@ -19,14 +19,8 @@ import (
 )
 
 const (
-	defaultBashTimeout = 2 * time.Minute
-	maxBashTimeout     = 10 * time.Minute
-	replyGrace         = 30 * time.Second
-	copyTimeout        = 10 * time.Minute
-	fileTimeout        = 2 * time.Minute
-	handsTimeout       = 2 * time.Minute
-	defaultReadLimit   = 2000
-	clientByre         = "/Applications/Byre.app/Contents/Helpers/byre"
+	defaultReadLimit = 2000
+	clientByre       = "/Applications/Byre.app/Contents/Helpers/byre"
 )
 
 func (m *Manager) clientTools(l *live) []mcp.Tool {
@@ -53,7 +47,7 @@ func (m *Manager) clientTools(l *live) []mcp.Tool {
 				"properties": {
 					"client": {"type": "string", "description": "The client's name from list_clients, or its id when several are connected from that Mac."},
 					"command": {"type": "string"},
-					"timeout_ms": {"type": "integer", "description": "Kill the command after this long (default 120000, at most 600000)."}
+					"timeout_ms": {"type": "integer", "description": "Kill the command after this long (at most 600000)."}
 				},
 				"required": ["client", "command"]
 			}`),
@@ -319,18 +313,18 @@ func (m *Manager) clientBash(ctx context.Context, raw json.RawMessage) (string,
 	if err != nil {
 		return "", fmt.Errorf("malformed client_bash call: %w", err)
 	}
-	timeout, err := args.timeout()
+	err = args.check()
 	if err != nil {
 		return "", err
 	}
 
-	exitCode, output, err := m.runClientBash(ctx, args.Client, args.Command, timeout)
+	exitCode, output, err := m.runClientBash(ctx, args.Client, args.Command)
 	if err != nil {
 		return "", err
 	}
 	status := fmt.Sprintf("exit status %d", exitCode)
 	if exitCode == -1 {
-		status = fmt.Sprintf("killed after %s", timeout)
+		status = fmt.Sprintf("killed after %s", mcp.Timeout(ctx))
 	}
 	return status + "\n" + output, nil
 }
@@ -378,9 +372,7 @@ func (m *Manager) upload(ctx context.Context, client, full, dest string) error {
 	id := m.clients.AddTransfer(clients.Transfer{Dir: filepath.Dir(full), Name: filepath.Base(full)})
 	defer m.clients.RemoveTransfer(id)
 
-	cctx, cancel := context.WithTimeout(ctx, copyTimeout)
-	defer cancel()
-	_, err = m.clients.Call(cctx, client, api.ClientRequest{Op: api.Upload, Transfer: &id, Dest: &dest})
+	_, err = m.clients.Call(ctx, client, api.ClientRequest{Op: api.Upload, Transfer: &id, Dest: &dest})
 	return err
 }
 
@@ -410,7 +402,7 @@ func (m *Manager) clientOpen(ctx context.Context, l *live, raw json.RawMessage)
 	}
 
 	command := "open " + dir + "/" + shellQuote(name)
-	exitCode, output, err := m.runClientBash(ctx, args.Client, command, fileTimeout)
+	exitCode, output, err := m.runClientBash(ctx, args.Client, command)
 	if err != nil {
 		return "", err
 	}
@@ -445,9 +437,7 @@ func (m *Manager) showPage(ctx context.Context, l *live, raw json.RawMessage) (s
 	if u.Scheme != "http" && u.Scheme != "https" {
 		return "", fmt.Errorf("url %q isn't http or https", args.URL)
 	}
-	cctx, cancel := context.WithTimeout(ctx, fileTimeout)
-	defer cancel()
-	reply, err := m.clients.Call(cctx, args.Client, api.ClientRequest{Op: api.OpenPage, Task: &l.taskID, Url: &args.URL})
+	reply, err := m.clients.Call(ctx, args.Client, api.ClientRequest{Op: api.OpenPage, Task: &l.taskID, Url: &args.URL})
 	if err != nil {
 		return "", err
 	}
@@ -492,9 +482,7 @@ func (m *Manager) drivePage(ctx context.Context, l *live, raw json.RawMessage) m
 	default:
 		return mcp.TextResult(fmt.Sprintf("unknown op %q", args.Op), true)
 	}
-	cctx, cancel := context.WithTimeout(ctx, handsTimeout)
-	defer cancel()
-	reply, err := m.clients.Call(cctx, args.Client, req)
+	reply, err := m.clients.Call(ctx, args.Client, req)
 	if err != nil {
 		return mcp.TextResult(err.Error(), true)
 	}
@@ -540,9 +528,7 @@ func (m *Manager) show(ctx context.Context, l *live, raw json.RawMessage, tool s
 	} else if fi.IsDir() {
 		shown += "/"
 	}
-	cctx, cancel := context.WithTimeout(ctx, fileTimeout)
-	defer cancel()
-	_, err = m.clients.Call(cctx, args.Client, api.ClientRequest{Op: op, Task: &l.taskID, Path: &shown})
+	_, err = m.clients.Call(ctx, args.Client, api.ClientRequest{Op: op, Task: &l.taskID, Path: &shown})
 	if err != nil {
 		return "", err
 	}
@@ -581,9 +567,7 @@ func (m *Manager) clientDownload(ctx context.Context, l *live, raw json.RawMessa
 	id := m.clients.AddTransfer(clients.Transfer{Dir: tmp, Name: "archive.tgz", Receive: true})
 	defer m.clients.RemoveTransfer(id)
 
-	cctx, cancel := context.WithTimeout(ctx, copyTimeout)
-	defer cancel()
-	_, err = m.clients.Call(cctx, args.Client, api.ClientRequest{Op: api.Download, Path: &args.Path, Transfer: &id})
+	_, err = m.clients.Call(ctx, args.Client, api.ClientRequest{Op: api.Download, Path: &args.Path, Transfer: &id})
 	if err != nil {
 		return "", err
 	}
@@ -621,9 +605,7 @@ func (m *Manager) readClientFile(ctx context.Context, client, path string) ([]by
 	if err != nil {
 		return nil, err
 	}
-	cctx, cancel := context.WithTimeout(ctx, fileTimeout)
-	defer cancel()
-	reply, err := m.clients.Call(cctx, client, api.ClientRequest{Op: api.ReadFile, Path: &path})
+	reply, err := m.clients.Call(ctx, client, api.ClientRequest{Op: api.ReadFile, Path: &path})
 	if err != nil {
 		return nil, err
 	}
@@ -638,9 +620,7 @@ func (m *Manager) writeClientFile(ctx context.Context, client, path string, data
 	if err != nil {
 		return err
 	}
-	cctx, cancel := context.WithTimeout(ctx, fileTimeout)
-	defer cancel()
-	_, err = m.clients.Call(cctx, client, api.ClientRequest{Op: api.WriteFile, Path: &path, Data: &data})
+	_, err = m.clients.Call(ctx, client, api.ClientRequest{Op: api.WriteFile, Path: &path, Data: &data})
 	return err
 }
 
@@ -775,7 +755,7 @@ func clientShellPath(p string) (string, error) {
 
 func (m *Manager) runClientByre(ctx context.Context, client, sub, args string) (string, error) {
 	command := clientByre + " " + sub + args
-	exitCode, output, err := m.runClientBash(ctx, client, command, fileTimeout)
+	exitCode, output, err := m.runClientBash(ctx, client, command)
 	if err != nil {
 		return "", err
 	}
@@ -785,9 +765,13 @@ func (m *Manager) runClientByre(ctx context.Context, client, sub, args string) (
 	return output, nil
 }
 
-func (m *Manager) runClientBash(ctx context.Context, client, command string, timeout time.Duration) (int, string, error) {
-	ms := int(timeout.Milliseconds())
-	cctx, cancel := context.WithTimeout(ctx, timeout+replyGrace)
+func untilReply(ctx context.Context) (context.Context, context.CancelFunc) {
+	return context.WithTimeout(context.WithoutCancel(ctx), mcp.Timeout(ctx)+mcp.Grace)
+}
+
+func (m *Manager) runClientBash(ctx context.Context, client, command string) (int, string, error) {
+	ms := int(mcp.Timeout(ctx).Milliseconds())
+	cctx, cancel := untilReply(ctx)
 	defer cancel()
 	reply, err := m.clients.Call(cctx, client, api.ClientRequest{Op: api.Bash, Command: &command, TimeoutMs: &ms})
 	if err != nil {
@@ -814,18 +798,8 @@ func (m *Manager) clientHands(ctx context.Context, raw json.RawMessage) mcp.Resu
 	if args.Arguments == nil {
 		args.Arguments = &map[string]any{}
 	}
-
-	ms := func(m map[string]any, key string) time.Duration {
-		v, _ := m[key].(float64)
-		return time.Duration(v) * time.Millisecond
-	}
-	timeout := handsTimeout + ms(*args.Arguments, "wait_ms") + 2*ms(*args.Arguments, "timeout_ms")
-	steps, _ := (*args.Arguments)["steps"].([]any)
-	for _, s := range steps {
-		step, _ := s.(map[string]any)
-		timeout += ms(step, "wait")
-	}
-	cctx, cancel := context.WithTimeout(ctx, timeout)
+	(*args.Arguments)["timeout_ms"] = mcp.Timeout(ctx).Milliseconds()
+	cctx, cancel := untilReply(ctx)
 	defer cancel()
 	reply, err := m.clients.Call(cctx, args.Client, api.ClientRequest{Op: api.Hands, Tool: &args.Tool, Arguments: args.Arguments})
 	if err != nil {
diff --git a/internal/agents/files.go b/internal/agents/files.go
index cc6ece0..879a34d 100644
--- a/internal/agents/files.go
+++ b/internal/agents/files.go
@@ -262,9 +262,7 @@ func (m *Manager) grep(ctx context.Context, l *live, raw json.RawMessage) (strin
 			return "", err
 		}
 	}
-	cctx, cancel := context.WithTimeout(ctx, fileTimeout)
-	defer cancel()
-	return grep.Search(cctx, args.Pattern, l.dir, path, args.options())
+	return grep.Search(ctx, args.Pattern, l.dir, path, args.options())
 }
 
 type listArgs struct {
diff --git a/internal/agents/sign.go b/internal/agents/sign.go
index b46a8ab..639315f 100644
--- a/internal/agents/sign.go
+++ b/internal/agents/sign.go
@@ -10,7 +10,10 @@ import (
 	"g.fc.run/ai/byre/internal/clients"
 )
 
-const signTimeout = 2 * time.Minute
+const (
+	signTimeout = 2 * time.Minute
+	replyGrace  = 30 * time.Second
+)
 
 func (m *Manager) signer(ctx context.Context, user api.User) func(payload []byte) ([]byte, error) {
 	return func(payload []byte) ([]byte, error) {
diff --git a/internal/codex/session.go b/internal/codex/session.go
index e33a90d..6e1c6c5 100644
--- a/internal/codex/session.go
+++ b/internal/codex/session.go
@@ -270,7 +270,7 @@ func dynamicTools(servers []*mcp.Server) []DynamicToolSpec {
 				Type:        DynamicToolSpecTypeFunction,
 				Name:        t.Name,
 				Description: t.Description,
-				InputSchema: t.InputSchema,
+				InputSchema: t.Schema(),
 			})
 		}
 		specs = append(specs, DynamicToolSpec{
diff --git a/internal/mcp/server.go b/internal/mcp/server.go
index 7a4ced0..eebe72f 100644
--- a/internal/mcp/server.go
+++ b/internal/mcp/server.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"time"
 )
 
 const protocolVersion = "2025-06-18"
@@ -39,7 +40,72 @@ func TextResult(text string, isError bool) Result {
 	return Result{Content: []Content{{Type: "text", Text: text}}, IsError: isError}
 }
 
+const (
+	MaxTimeout = 10 * time.Minute
+	Grace      = 5 * time.Second
+)
+
+type timeoutKey struct{}
+
+func Timeout(ctx context.Context) time.Duration {
+	return ctx.Value(timeoutKey{}).(time.Duration)
+}
+
+func (t Tool) Schema() json.RawMessage {
+	s := map[string]any{}
+	err := json.Unmarshal(t.InputSchema, &s)
+	if err != nil {
+		panic(fmt.Sprintf("tool %s: input schema: %s", t.Name, err))
+	}
+	props, _ := s["properties"].(map[string]any)
+	if props == nil {
+		props = map[string]any{}
+		s["properties"] = props
+	}
+	if props["timeout_ms"] == nil {
+		props["timeout_ms"] = map[string]any{"type": "integer", "description": fmt.Sprintf("Give up on the call after this long (at most %d).", MaxTimeout.Milliseconds())}
+	}
+	required, _ := s["required"].([]any)
+	s["required"] = append(required, "timeout_ms")
+	out, err := json.Marshal(s)
+	if err != nil {
+		panic(fmt.Sprintf("tool %s: input schema: %s", t.Name, err))
+	}
+	return out
+}
+
 func (t Tool) Call(ctx context.Context, args json.RawMessage) Result {
+	p := struct {
+		TimeoutMs *int `json:"timeout_ms"`
+	}{}
+	err := json.Unmarshal(args, &p)
+	if err != nil {
+		return TextResult(fmt.Sprintf("malformed %s call: %s", t.Name, err), true)
+	}
+	if p.TimeoutMs == nil || *p.TimeoutMs <= 0 || *p.TimeoutMs > int(MaxTimeout.Milliseconds()) {
+		return TextResult(fmt.Sprintf("timeout_ms is required, between 1 and %d", MaxTimeout.Milliseconds()), true)
+	}
+	timeout := time.Duration(*p.TimeoutMs) * time.Millisecond
+
+	cctx, cancel := context.WithTimeout(context.WithValue(ctx, timeoutKey{}, timeout), timeout)
+	defer cancel()
+	done := make(chan Result, 1)
+	go func() {
+		done <- t.run(cctx, args)
+	}()
+	late := time.NewTimer(timeout + Grace)
+	defer late.Stop()
+	select {
+	case res := <-done:
+		return res
+	case <-ctx.Done():
+		return TextResult(ctx.Err().Error(), true)
+	case <-late.C:
+		return TextResult(fmt.Sprintf("%s gave no result within %s", t.Name, timeout), true)
+	}
+}
+
+func (t Tool) run(ctx context.Context, args json.RawMessage) Result {
 	if t.Rich != nil {
 		return t.Rich(ctx, args)
 	}
@@ -127,7 +193,7 @@ func (s *Server) dispatch(ctx context.Context, req request) (any, *rpcError) {
 	case "tools/list":
 		tools := []toolDesc{}
 		for _, t := range s.Tools {
-			tools = append(tools, toolDesc{Name: t.Name, Description: t.Description, InputSchema: t.InputSchema})
+			tools = append(tools, toolDesc{Name: t.Name, Description: t.Description, InputSchema: t.Schema()})
 		}
 		return map[string]any{"tools": tools}, nil