feat: add session show command

Author: tmuskal

docs/cli-reference.md

@@ -55,6 +55,10 @@ Create a new session identifier.
 
 List persisted sessions from `.agentpowershell/sessions.json`. Text mode includes the active flag, working directory, created/last/expires timestamps, and policy path. JSON mode emits a stable summary shape.
 
+### `session show [session-id]`
+
+Show one persisted session from `.agentpowershell/sessions.json`. If `session-id` is omitted, the command returns the most recently created session. Missing sessions return `status: not-found` and a non-zero exit code.
+
 ### `session destroy <session-id>`
 
 Remove a session from the session store.

docs/getting-started.md

@@ -45,6 +45,12 @@ List sessions:
 dotnet run --project src/AgentPowerShell.Cli -- session list
 ```
 
+Show the most recent session:
+
+```powershell
+dotnet run --project src/AgentPowerShell.Cli -- session show --output json
+```
+
 Execute an explicit inline PowerShell command through the current runtime path:
 
 ```powershell

src/AgentPowerShell.Cli/CliApp.cs

@@ -214,6 +214,41 @@ private static Command BuildSessionCommand(Option<string> outputOption)
             }
         }, outputOption);
 
+        var show = new Command("show", "Show one session");
+        var showSessionId = new Argument<string?>("session-id", () => null);
+        show.AddArgument(showSessionId);
+        show.SetHandler(async (string? id, string output) =>
+        {
+            using var store = new SessionStore(GetSessionsPath());
+            await store.LoadAsync(CancellationToken.None).ConfigureAwait(false);
+            var sessions = await store.ListAsync(CancellationToken.None).ConfigureAwait(false);
+
+            var session = string.IsNullOrWhiteSpace(id)
+                ? sessions.Count == 0 ? null : sessions[^1]
+                : await store.GetAsync(id, CancellationToken.None).ConfigureAwait(false);
+
+            if (session is null)
+            {
+                Emit(output, new
+                {
+                    command = "session show",
+                    sessionId = id,
+                    status = "not-found"
+                });
+                Environment.ExitCode = 1;
+                return;
+            }
+
+            var summary = ToSessionSummary(session);
+            if (string.Equals(output, "json", StringComparison.OrdinalIgnoreCase))
+            {
+                Emit(output, new { command = "session show", sessionId = summary.Id, session = summary });
+                return;
+            }
+
+            Console.WriteLine($"{summary.Id} | active={summary.IsActive} | cwd={summary.WorkingDirectory} | created={summary.CreatedAt:O} | last={summary.LastActivityAt:O} | expires={summary.ExpiresAt:O} | policy={summary.PolicyPath}");
+        }, showSessionId, outputOption);
+
         var destroy = new Command("destroy", "Destroy session");
         var sessionId = new Argument<string>("session-id");
         destroy.AddArgument(sessionId);
@@ -227,6 +262,7 @@ private static Command BuildSessionCommand(Option<string> outputOption)
 
         command.AddCommand(create);
         command.AddCommand(list);
+        command.AddCommand(show);
         command.AddCommand(destroy);
         return command;
     }

tests/AgentPowerShell.Tests/ExecutionPolicyTests.cs

@@ -1510,6 +1510,77 @@ public async Task CliApp_SessionList_Text_Mode_Includes_Usable_Metadata()
         }
     }
 
+    [Fact]
+    public async Task CliApp_SessionShow_Json_Mode_Returns_Latest_Session_By_Default()
+    {
+        var root = Path.Combine(Path.GetTempPath(), $"{Guid.NewGuid():N}-cli-session-show-json");
+        Directory.CreateDirectory(root);
+        var originalDirectory = Environment.CurrentDirectory;
+        var originalOut = Console.Out;
+
+        try
+        {
+            Environment.CurrentDirectory = root;
+
+            using (var store = new SessionStore(Path.Combine(root, ".agentpowershell", "sessions.json")))
+            {
+                await store.LoadAsync(CancellationToken.None);
+                await store.GetOrCreateAsync("session-a", root, new AgentPowerShellConfig().Sessions, CancellationToken.None);
+                await Task.Delay(10);
+                await store.GetOrCreateAsync("session-b", root, new AgentPowerShellConfig().Sessions, CancellationToken.None);
+            }
+
+            using var writer = new StringWriter();
+            Console.SetOut(writer);
+
+            Assert.Equal(0, CliApp.Run(["session", "show", "--output", "json"]));
+            var payload = writer.ToString();
+            Assert.Contains("\"command\":\"session show\"", payload, StringComparison.Ordinal);
+            Assert.Contains("\"sessionId\":\"session-b\"", payload, StringComparison.Ordinal);
+            Assert.Contains("\"id\":\"session-b\"", payload, StringComparison.Ordinal);
+        }
+        finally
+        {
+            Console.SetOut(originalOut);
+            Environment.CurrentDirectory = originalDirectory;
+            if (Directory.Exists(root))
+            {
+                Directory.Delete(root, recursive: true);
+            }
+        }
+    }
+
+    [Fact]
+    public void CliApp_SessionShow_Returns_NotFound_For_Missing_Session()
+    {
+        var root = Path.Combine(Path.GetTempPath(), $"{Guid.NewGuid():N}-cli-session-show-missing");
+        Directory.CreateDirectory(root);
+        var originalDirectory = Environment.CurrentDirectory;
+        var originalOut = Console.Out;
+
+        try
+        {
+            Environment.CurrentDirectory = root;
+            using var writer = new StringWriter();
+            Console.SetOut(writer);
+
+            Assert.Equal(1, CliApp.Run(["session", "show", "missing-session", "--output", "json"]));
+            var payload = writer.ToString();
+            Assert.Contains("\"command\":\"session show\"", payload, StringComparison.Ordinal);
+            Assert.Contains("\"status\":\"not-found\"", payload, StringComparison.Ordinal);
+            Assert.Contains("\"sessionId\":\"missing-session\"", payload, StringComparison.Ordinal);
+        }
+        finally
+        {
+            Console.SetOut(originalOut);
+            Environment.CurrentDirectory = originalDirectory;
+            if (Directory.Exists(root))
+            {
+                Directory.Delete(root, recursive: true);
+            }
+        }
+    }
+
     [Fact]
     public void DaemonLaunchResolver_Uses_Explicit_Dll_Path_When_Configured()
     {