diff --git a/src/ClaudeDo.Worker/Prime/PrimePrompts.cs b/src/ClaudeDo.Worker/Prime/PrimePrompts.cs
new file mode 100644
index 00000000..a1533344
--- /dev/null
+++ b/src/ClaudeDo.Worker/Prime/PrimePrompts.cs
@@ -0,0 +1,31 @@
+namespace ClaudeDo.Worker.Prime;
+
+/// <summary>Prompts and CLI args for the non-daily-prep Prime actions.
+/// The daily-prep ones live in <see cref="DailyPrepPrompt"/>.</summary>
+public static class PrimePrompts
+{
+    /// <summary>The whole point of a ping is to open the usage window, so it asks for the
+    /// cheapest possible answer. Not user-editable — a schedule's prompt override is ignored
+    /// for this kind.</summary>
+    public const string PingPrompt = "Reply with the single word: ok";
+
+    /// <summary>No tools at all: --strict-mcp-config without a --mcp-config argument loads no
+    /// MCP server, and one turn leaves no room to act on a tool result anyway.</summary>
+    public static IReadOnlyList<string> BuildPingArgs() =>
+    [
+        "-p", "--output-format", "stream-json", "--verbose",
+        "--permission-mode", "default",
+        "--max-turns", "1",
+        "--strict-mcp-config",
+    ];
+
+    /// <summary>ClaudeDo's MCP server only — no Read/Write/Edit/Bash. An unattended 07:00 run
+    /// may create and queue tasks; it may not touch the filesystem.</summary>
+    public static IReadOnlyList<string> BuildCustomArgs(int maxTurns) =>
+    [
+        "-p", "--output-format", "stream-json", "--verbose",
+        "--permission-mode", "acceptEdits",
+        "--max-turns", maxTurns.ToString(),
+        "--allowedTools", "mcp__claudedo",
+    ];
+}
diff --git a/src/ClaudeDo.Worker/Prime/PrimeRunner.cs b/src/ClaudeDo.Worker/Prime/PrimeRunner.cs
index 35d46bb6..91616c2e 100644
--- a/src/ClaudeDo.Worker/Prime/PrimeRunner.cs
+++ b/src/ClaudeDo.Worker/Prime/PrimeRunner.cs
@@ -1,4 +1,5 @@
 using ClaudeDo.Data;
+using ClaudeDo.Data.Models;
 using ClaudeDo.Data.Repositories;
 using ClaudeDo.Worker.Runner;
 using Microsoft.EntityFrameworkCore;
@@ -33,9 +34,27 @@ public sealed class PrimeRunner : IPrimeRunner
 
     public async Task<PrimeRunOutcome> FireAsync(PrimeScheduleDto schedule, CancellationToken ct)
     {
+        // One gate for all kinds — two schedules must never run at the same time.
         if (!await _gate.WaitAsync(0, ct))
-            return new PrimeRunOutcome(false, "Daily prep already running");
+            return new PrimeRunOutcome(false, "Prime run already running");
 
+        try
+        {
+            return schedule.Kind switch
+            {
+                PrimeActionKind.FillMyDay => await RunFillMyDayAsync(schedule, ct),
+                PrimeActionKind.Custom => await RunCustomAsync(schedule, ct),
+                _ => await RunPingAsync(ct),
+            };
+        }
+        finally
+        {
+            _gate.Release();
+        }
+    }
+
+    private async Task<PrimeRunOutcome> RunFillMyDayAsync(PrimeScheduleDto schedule, CancellationToken ct)
+    {
         var success = false;
         try
         {
@@ -45,8 +64,7 @@ public sealed class PrimeRunner : IPrimeRunner
 
             await _broadcaster.PrepStartedAsync();
 
-            var cwd = Paths.AppDataRoot();
-            Directory.CreateDirectory(cwd);
+            var cwd = Cwd();
 
             int maxTasks;
             await using (var dbCtx = await _dbFactory.CreateDbContextAsync(ct))
@@ -57,13 +75,12 @@ public sealed class PrimeRunner : IPrimeRunner
 
             var today = DateOnly.FromDateTime(_clock.Now.LocalDateTime);
             var prompt = DailyPrepPrompt.BuildPrompt(maxTasks, today, schedule.PromptOverride);
-            var args = DailyPrepPrompt.BuildArgs(MaxTurns);
 
             using var timeoutCts = CancellationTokenSource.CreateLinkedTokenSource(ct);
             timeoutCts.CancelAfter(FireTimeout);
 
             var result = await _claude.RunAsync(
-                arguments: args,
+                arguments: DailyPrepPrompt.BuildArgs(MaxTurns),
                 prompt: prompt,
                 workingDirectory: cwd,
                 onStdoutLine: async line =>
@@ -90,7 +107,57 @@ public sealed class PrimeRunner : IPrimeRunner
         finally
         {
             await _broadcaster.PrepFinishedAsync(success);
-            _gate.Release();
         }
     }
+
+    private Task<PrimeRunOutcome> RunPingAsync(CancellationToken ct) =>
+        RunQuietAsync(PrimePrompts.BuildPingArgs(), PrimePrompts.PingPrompt, "Ping complete", "Ping", ct);
+
+    private Task<PrimeRunOutcome> RunCustomAsync(PrimeScheduleDto schedule, CancellationToken ct)
+    {
+        var prompt = schedule.PromptOverride;
+        if (string.IsNullOrWhiteSpace(prompt))
+            return Task.FromResult(new PrimeRunOutcome(false, "Custom schedule has no prompt"));
+
+        return RunQuietAsync(PrimePrompts.BuildCustomArgs(MaxTurns), prompt, "Custom run complete", "Custom", ct);
+    }
+
+    /// <summary>Ping and Custom deliberately write no log file and raise no Prep* events — the
+    /// prep log belongs to the MyDay selection and would otherwise be overwritten with noise.</summary>
+    private async Task<PrimeRunOutcome> RunQuietAsync(
+        IReadOnlyList<string> args, string prompt, string successMessage, string label, CancellationToken ct)
+    {
+        try
+        {
+            using var timeoutCts = CancellationTokenSource.CreateLinkedTokenSource(ct);
+            timeoutCts.CancelAfter(FireTimeout);
+
+            var result = await _claude.RunAsync(
+                arguments: args,
+                prompt: prompt,
+                workingDirectory: Cwd(),
+                onStdoutLine: _ => Task.CompletedTask,
+                ct: timeoutCts.Token);
+
+            return result.IsSuccess
+                ? new PrimeRunOutcome(true, successMessage)
+                : new PrimeRunOutcome(false, $"exit code {result.ExitCode}");
+        }
+        catch (OperationCanceledException) when (!ct.IsCancellationRequested)
+        {
+            return new PrimeRunOutcome(false, $"timed out after {FireTimeout.TotalMinutes:0} min");
+        }
+        catch (Exception ex)
+        {
+            _logger.LogWarning(ex, "Prime {Label} run failed", label);
+            return new PrimeRunOutcome(false, ex.Message);
+        }
+    }
+
+    private static string Cwd()
+    {
+        var cwd = Paths.AppDataRoot();
+        Directory.CreateDirectory(cwd);
+        return cwd;
+    }
 }
diff --git a/src/ClaudeDo.Worker/Prime/PrimeScheduleDto.cs b/src/ClaudeDo.Worker/Prime/PrimeScheduleDto.cs
index ec138255..0719eb99 100644
--- a/src/ClaudeDo.Worker/Prime/PrimeScheduleDto.cs
+++ b/src/ClaudeDo.Worker/Prime/PrimeScheduleDto.cs
@@ -1,3 +1,5 @@
+using ClaudeDo.Data.Models;
+
 namespace ClaudeDo.Worker.Prime;
 
 public sealed record PrimeScheduleDto(
@@ -6,4 +8,5 @@ public sealed record PrimeScheduleDto(
     TimeSpan TimeOfDay,
     bool Enabled,
     DateTimeOffset? LastRunAt,
-    string? PromptOverride);
+    string? PromptOverride,
+    PrimeActionKind Kind);
diff --git a/src/ClaudeDo.Worker/Prime/PrimeScheduler.cs b/src/ClaudeDo.Worker/Prime/PrimeScheduler.cs
index 2e7b2543..0229c13a 100644
--- a/src/ClaudeDo.Worker/Prime/PrimeScheduler.cs
+++ b/src/ClaudeDo.Worker/Prime/PrimeScheduler.cs
@@ -102,7 +102,7 @@ public sealed class PrimeScheduler : BackgroundService
     }
 
     private static PrimeScheduleDto ToDto(Data.Models.PrimeScheduleEntity e) =>
-        new(e.Id, (int)e.Days, e.TimeOfDay, e.Enabled, e.LastRunAt, e.PromptOverride);
+        new(e.Id, (int)e.Days, e.TimeOfDay, e.Enabled, e.LastRunAt, e.PromptOverride, e.Kind);
 
     private async Task FireAsync(PrimeScheduleDto schedule, CancellationToken ct)
     {
diff --git a/tests/ClaudeDo.Worker.Tests/Prime/PrimeRunnerTests.cs b/tests/ClaudeDo.Worker.Tests/Prime/PrimeRunnerTests.cs
index e7acdc30..0e7b95f6 100644
--- a/tests/ClaudeDo.Worker.Tests/Prime/PrimeRunnerTests.cs
+++ b/tests/ClaudeDo.Worker.Tests/Prime/PrimeRunnerTests.cs
@@ -1,3 +1,4 @@
+using ClaudeDo.Data.Models;
 using ClaudeDo.Worker.Prime;
 using ClaudeDo.Worker.Runner;
 using ClaudeDo.Worker.Tests.Infrastructure;
@@ -22,6 +23,9 @@ public class PrimeRunnerTests : IDisposable
         private readonly string[] _emitLines;
         private readonly string? _result;
 
+        public IReadOnlyList<string>? LastArguments { get; private set; }
+        public string? LastPrompt { get; private set; }
+
         public FakeClaudeProcess(TimeSpan delay = default, int exitCode = 0, string[]? emitLines = null, string? result = null)
         {
             _delay = delay;
@@ -37,6 +41,9 @@ public class PrimeRunnerTests : IDisposable
             Func<string, Task> onStdoutLine,
             CancellationToken ct)
         {
+            LastArguments = arguments;
+            LastPrompt = prompt;
+
             if (_delay > TimeSpan.Zero)
                 await Task.Delay(_delay, ct);
 
@@ -72,7 +79,10 @@ public class PrimeRunnerTests : IDisposable
             broadcaster);
 
     private static PrimeScheduleDto DefaultSchedule() =>
-        new(Guid.Empty, 0, TimeSpan.Zero, true, null, null);
+        new(Guid.Empty, 0, TimeSpan.Zero, true, null, null, PrimeActionKind.FillMyDay);
+
+    private static PrimeScheduleDto Schedule(PrimeActionKind kind, string? promptOverride = null) =>
+        new(Guid.Empty, 0, TimeSpan.Zero, true, null, promptOverride, kind);
 
     [Fact]
     public async Task FireAsync_returns_success_when_claude_exits_zero()
@@ -114,7 +124,7 @@ public class PrimeRunnerTests : IDisposable
         var broadcaster = new RecordingPrimeBroadcaster();
         var claude = new FakeClaudeProcess(emitLines: ["{\"a\":1}", "{\"b\":2}"], exitCode: 0, result: "ok");
         var runner = NewRunner(claude, broadcaster);
-        var schedule = new PrimeScheduleDto(Guid.Empty, 0, TimeSpan.Zero, true, null, null);
+        var schedule = DefaultSchedule();
 
         var outcome = await runner.FireAsync(schedule, CancellationToken.None);
 
@@ -133,7 +143,7 @@ public class PrimeRunnerTests : IDisposable
 
         var claude = new FakeClaudeProcess(emitLines: new[] { "lineA", "lineB" }, exitCode: 0, result: "ok");
         var runner = NewRunner(claude, new RecordingPrimeBroadcaster());
-        await runner.FireAsync(new PrimeScheduleDto(Guid.Empty, 0, TimeSpan.Zero, true, null, null), CancellationToken.None);
+        await runner.FireAsync(DefaultSchedule(), CancellationToken.None);
 
         var contents = await File.ReadAllTextAsync(path);
         Assert.Contains("lineA", contents);
@@ -142,9 +152,105 @@ public class PrimeRunnerTests : IDisposable
         // Truncation: a second run with different lines replaces the file.
         var claude2 = new FakeClaudeProcess(emitLines: new[] { "lineC" }, exitCode: 0, result: "ok");
         var runner2 = NewRunner(claude2, new RecordingPrimeBroadcaster());
-        await runner2.FireAsync(new PrimeScheduleDto(Guid.Empty, 0, TimeSpan.Zero, true, null, null), CancellationToken.None);
+        await runner2.FireAsync(DefaultSchedule(), CancellationToken.None);
         var after = await File.ReadAllTextAsync(path);
         Assert.DoesNotContain("lineA", after);
         Assert.Contains("lineC", after);
     }
+
+    [Fact]
+    public async Task Ping_runs_a_single_turn_with_no_mcp_servers()
+    {
+        var claude = new FakeClaudeProcess(exitCode: 0, result: "ok");
+        var runner = NewRunner(claude, new RecordingPrimeBroadcaster());
+
+        var outcome = await runner.FireAsync(Schedule(PrimeActionKind.Ping), CancellationToken.None);
+
+        Assert.True(outcome.Success);
+        Assert.Contains("--strict-mcp-config", claude.LastArguments!);
+        var turnsIndex = claude.LastArguments!.ToList().IndexOf("--max-turns");
+        Assert.Equal("1", claude.LastArguments[turnsIndex + 1]);
+        Assert.DoesNotContain(DailyPrepPrompt.SetMyDayTool, claude.LastArguments);
+    }
+
+    [Fact]
+    public async Task Ping_writes_no_prep_log_and_raises_no_prep_events()
+    {
+        var path = DailyPrepPrompt.LogPath();
+        Directory.CreateDirectory(Path.GetDirectoryName(path)!);
+        await File.WriteAllTextAsync(path, "previous fill-my-day run");
+
+        var broadcaster = new RecordingPrimeBroadcaster();
+        var claude = new FakeClaudeProcess(emitLines: ["ping-line"], exitCode: 0, result: "ok");
+        var runner = NewRunner(claude, broadcaster);
+
+        await runner.FireAsync(Schedule(PrimeActionKind.Ping), CancellationToken.None);
+
+        Assert.Equal("previous fill-my-day run", await File.ReadAllTextAsync(path));
+        Assert.Equal(0, broadcaster.StartedCount);
+        Assert.Empty(broadcaster.Lines);
+        Assert.Empty(broadcaster.FinishedResults);
+    }
+
+    [Fact]
+    public async Task Custom_sends_the_prompt_override_verbatim_with_claudedo_mcp_only()
+    {
+        var claude = new FakeClaudeProcess(exitCode: 0, result: "ok");
+        var runner = NewRunner(claude, new RecordingPrimeBroadcaster());
+
+        var outcome = await runner.FireAsync(
+            Schedule(PrimeActionKind.Custom, "Queue the three oldest idle tasks."),
+            CancellationToken.None);
+
+        Assert.True(outcome.Success);
+        Assert.Equal("Queue the three oldest idle tasks.", claude.LastPrompt);
+        Assert.Contains("--allowedTools", claude.LastArguments!);
+        Assert.Contains("mcp__claudedo", claude.LastArguments!);
+        Assert.DoesNotContain("--strict-mcp-config", claude.LastArguments!);
+    }
+
+    [Fact]
+    public async Task Custom_writes_no_prep_log_and_raises_no_prep_events()
+    {
+        var path = DailyPrepPrompt.LogPath();
+        Directory.CreateDirectory(Path.GetDirectoryName(path)!);
+        await File.WriteAllTextAsync(path, "previous fill-my-day run");
+
+        var broadcaster = new RecordingPrimeBroadcaster();
+        var claude = new FakeClaudeProcess(emitLines: ["custom-line"], exitCode: 0, result: "ok");
+        var runner = NewRunner(claude, broadcaster);
+
+        await runner.FireAsync(Schedule(PrimeActionKind.Custom, "do a thing"), CancellationToken.None);
+
+        Assert.Equal("previous fill-my-day run", await File.ReadAllTextAsync(path));
+        Assert.Equal(0, broadcaster.StartedCount);
+        Assert.Empty(broadcaster.FinishedResults);
+    }
+
+    [Fact]
+    public async Task FillMyDay_still_appends_the_prompt_override()
+    {
+        var claude = new FakeClaudeProcess(exitCode: 0, result: "ok");
+        var runner = NewRunner(claude, new RecordingPrimeBroadcaster());
+
+        await runner.FireAsync(
+            Schedule(PrimeActionKind.FillMyDay, "Prefer the LogX tasks."),
+            CancellationToken.None);
+
+        Assert.Contains("Prefer the LogX tasks.", claude.LastPrompt);
+        Assert.Contains(DailyPrepPrompt.SetMyDayTool, claude.LastArguments!);
+    }
+
+    [Fact]
+    public async Task Gate_is_shared_across_kinds()
+    {
+        var runner = NewRunner(claudeDelay: TimeSpan.FromSeconds(2));
+
+        var first = runner.FireAsync(Schedule(PrimeActionKind.Ping), CancellationToken.None);
+        var second = await runner.FireAsync(Schedule(PrimeActionKind.FillMyDay), CancellationToken.None);
+
+        Assert.False(second.Success);
+        Assert.Contains("already running", second.Message, StringComparison.OrdinalIgnoreCase);
+        await first;
+    }
 }