diff --git a/Examples/Tests/ExampleTests/QueryingTests.swift b/Examples/Tests/ExampleTests/QueryingTests.swift
index 39606a7..0ca0b25 100644
--- a/Examples/Tests/ExampleTests/QueryingTests.swift
+++ b/Examples/Tests/ExampleTests/QueryingTests.swift
@@ -1,17 +1,175 @@
 import ExampleCode
+import Foundation
 import LibTmux
 import Testing
 import TmuxFixture
 
+private enum ArenaRoute: Equatable {
+    case fixture
+    case arena(socketPath: String, tmuxExecutable: String)
+}
+
+private enum ArenaContractError: Error {
+    case incomplete
+    case wrongArtifact
+}
+
+private struct ArenaEvidence: Codable {
+    let artifact: String
+    let challenge: String
+    let schema: Int
+    let serverProcessID: Int
+    let socketPath: String
+
+    enum CodingKeys: String, CodingKey {
+        case artifact
+        case challenge
+        case schema
+        case serverProcessID = "server_pid"
+        case socketPath = "socket_path"
+    }
+}
+
+private func arenaRoute(environment: [String: String]) throws -> ArenaRoute {
+    guard let descriptor = environment["LIBTMUX_ARENA_DESCRIPTOR"], !descriptor.isEmpty else {
+        return .fixture
+    }
+    guard let artifact = environment["LIBTMUX_ARENA_ARTIFACT"], !artifact.isEmpty,
+        let socketPath = environment["LIBTMUX_SOCKET_PATH"], !socketPath.isEmpty,
+        let tmuxExecutable = environment["LIBTMUX_TMUX_BIN"], !tmuxExecutable.isEmpty
+    else {
+        throw ArenaContractError.incomplete
+    }
+    guard artifact == "swift-querying" else {
+        throw ArenaContractError.wrongArtifact
+    }
+    return .arena(socketPath: socketPath, tmuxExecutable: tmuxExecutable)
+}
+
+private func arenaServer(for route: ArenaRoute) throws -> Server? {
+    guard case let .arena(socketPath, tmuxExecutable) = route else { return nil }
+    return try Server(socketPath: socketPath, tmuxExecutable: tmuxExecutable)
+}
+
+private func assertThreeListings(on server: Server) async throws {
+    let (sessions, windows, panes) = try await askWhatExists(server)
+    try #require(sessions == 1)
+    try #require(windows == 1)
+    try #require(panes == 1)
+}
+
+private func arenaEvidence(for server: Server, requestedSocket: String) async throws -> Data {
+    let serverProcessID = try #require(try await server.serverProcessID())
+    let actualSocketPath = try #require(try await server.format("#{socket_path}"))
+    try #require(actualSocketPath == requestedSocket)
+    let challenge = try #require(try await server.format("#{@libtmux_arena_challenge}"))
+    try #require(!challenge.isEmpty)
+    return try JSONEncoder().encode(
+        ArenaEvidence(
+            artifact: "swift-querying",
+            challenge: challenge,
+            schema: 1,
+            serverProcessID: serverProcessID,
+            socketPath: actualSocketPath
+        )
+    )
+}
+
 @Suite("querying", .timeLimit(.minutes(1)))
 struct QueryingTests {
+    @Test("arena aliases do not replace the fixture")
+    func arenaAliasesDoNotReplaceTheFixture() throws {
+        let route = try arenaRoute(
+            environment: [
+                "LIBTMUX_ARENA_DESCRIPTOR": "",
+                "LIBTMUX_ARENA_ARTIFACT": "swift-querying",
+                "LIBTMUX_SOCKET_PATH": "/not-an-arena-socket",
+                "LIBTMUX_TMUX_BIN": "/not-an-arena-tmux",
+            ]
+        )
+
+        #expect(route == .fixture)
+    }
+
+    @Test("an activated arena contract fails closed before server creation")
+    func activatedArenaContractFailsClosed() {
+        for environment in [
+            ["LIBTMUX_ARENA_DESCRIPTOR": "enabled"],
+            [
+                "LIBTMUX_ARENA_DESCRIPTOR": "enabled",
+                "LIBTMUX_ARENA_ARTIFACT": "",
+                "LIBTMUX_SOCKET_PATH": "/arena.sock",
+                "LIBTMUX_TMUX_BIN": "/usr/bin/tmux",
+            ],
+            [
+                "LIBTMUX_ARENA_DESCRIPTOR": "enabled",
+                "LIBTMUX_ARENA_ARTIFACT": "swift-querying",
+                "LIBTMUX_SOCKET_PATH": "",
+                "LIBTMUX_TMUX_BIN": "/usr/bin/tmux",
+            ],
+            [
+                "LIBTMUX_ARENA_DESCRIPTOR": "enabled",
+                "LIBTMUX_ARENA_ARTIFACT": "swift-querying",
+                "LIBTMUX_SOCKET_PATH": "/arena.sock",
+                "LIBTMUX_TMUX_BIN": "",
+            ],
+            [
+                "LIBTMUX_ARENA_DESCRIPTOR": "enabled",
+                "LIBTMUX_ARENA_ARTIFACT": "other-example",
+                "LIBTMUX_SOCKET_PATH": "/arena.sock",
+                "LIBTMUX_TMUX_BIN": "/usr/bin/tmux",
+            ],
+        ] {
+            #expect(throws: ArenaContractError.self) {
+                try arenaRoute(environment: environment)
+            }
+        }
+    }
+
+    @Test("the arena route uses a borrowed real server and encodes its evidence")
+    func arenaRouteUsesBorrowedServerAndEncodesEvidence() async throws {
+        try await withTmuxServer { owner in
+            let socketPath = try #require(try await owner.format("#{socket_path}"))
+            let challenge = "arena-challenge"
+            _ = try await owner.run(
+                TmuxCommand("set-option", ["-g", "@libtmux_arena_challenge", challenge])
+            )
+            let route = try arenaRoute(
+                environment: [
+                    "LIBTMUX_ARENA_DESCRIPTOR": "enabled",
+                    "LIBTMUX_ARENA_ARTIFACT": "swift-querying",
+                    "LIBTMUX_SOCKET_PATH": socketPath,
+                    "LIBTMUX_TMUX_BIN": owner.tmuxExecutable,
+                ]
+            )
+            let borrowed = try #require(try arenaServer(for: route))
+
+            #expect(borrowed.tmuxExecutable == owner.tmuxExecutable)
+            try await assertThreeListings(on: borrowed)
+            let evidence = try await arenaEvidence(for: borrowed, requestedSocket: socketPath)
+            let decoded = try JSONDecoder().decode(ArenaEvidence.self, from: evidence)
+
+            #expect(decoded.artifact == "swift-querying")
+            #expect(decoded.challenge == challenge)
+            #expect(decoded.socketPath == socketPath)
+            #expect(decoded.serverProcessID == (try await owner.serverProcessID()))
+            #expect(try await owner.serverProcessID() != nil)
+        }
+    }
+
     @Test("the three listings answer about a real server")
     func theThreeListings() async throws {
+        let route = try arenaRoute(environment: ProcessInfo.processInfo.environment)
+        if case let .arena(socketPath, _) = route {
+            let server = try #require(try arenaServer(for: route))
+            try await assertThreeListings(on: server)
+            let evidence = try await arenaEvidence(for: server, requestedSocket: socketPath)
+            print("LIBTMUX_ARENA_EVIDENCE=\(String(decoding: evidence, as: UTF8.self))")
+            return
+        }
+
         try await withTmuxServer { server in
-            let (sessions, windows, panes) = try await askWhatExists(server)
-            #expect(sessions == 1)
-            #expect(windows == 1)
-            #expect(panes == 1)
+            try await assertThreeListings(on: server)
         }
     }