diff --git a/src/ClaudeDo.Data/Repositories/ListRepository.cs b/src/ClaudeDo.Data/Repositories/ListRepository.cs
new file mode 100644
index 0000000..eb185ae
--- /dev/null
+++ b/src/ClaudeDo.Data/Repositories/ListRepository.cs
@@ -0,0 +1,124 @@
+using ClaudeDo.Data.Models;
+using Microsoft.Data.Sqlite;
+
+namespace ClaudeDo.Data.Repositories;
+
+public sealed class ListRepository
+{
+    private readonly SqliteConnectionFactory _factory;
+
+    public ListRepository(SqliteConnectionFactory factory) => _factory = factory;
+
+    public async Task AddAsync(ListEntity entity, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            INSERT INTO lists (id, name, created_at, working_dir, default_commit_type)
+            VALUES (@id, @name, @created_at, @working_dir, @default_commit_type)
+            """;
+        cmd.Parameters.AddWithValue("@id", entity.Id);
+        cmd.Parameters.AddWithValue("@name", entity.Name);
+        cmd.Parameters.AddWithValue("@created_at", entity.CreatedAt.ToString("o"));
+        cmd.Parameters.AddWithValue("@working_dir", (object?)entity.WorkingDir ?? DBNull.Value);
+        cmd.Parameters.AddWithValue("@default_commit_type", entity.DefaultCommitType);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task UpdateAsync(ListEntity entity, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            UPDATE lists SET name = @name, working_dir = @working_dir,
+                             default_commit_type = @default_commit_type
+            WHERE id = @id
+            """;
+        cmd.Parameters.AddWithValue("@id", entity.Id);
+        cmd.Parameters.AddWithValue("@name", entity.Name);
+        cmd.Parameters.AddWithValue("@working_dir", (object?)entity.WorkingDir ?? DBNull.Value);
+        cmd.Parameters.AddWithValue("@default_commit_type", entity.DefaultCommitType);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task DeleteAsync(string listId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "DELETE FROM lists WHERE id = @id";
+        cmd.Parameters.AddWithValue("@id", listId);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task<ListEntity?> GetByIdAsync(string listId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "SELECT id, name, created_at, working_dir, default_commit_type FROM lists WHERE id = @id";
+        cmd.Parameters.AddWithValue("@id", listId);
+
+        await using var reader = await cmd.ExecuteReaderAsync(ct);
+        if (!await reader.ReadAsync(ct)) return null;
+        return ReadList(reader);
+    }
+
+    public async Task<List<ListEntity>> GetAllAsync(CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "SELECT id, name, created_at, working_dir, default_commit_type FROM lists ORDER BY created_at";
+
+        await using var reader = await cmd.ExecuteReaderAsync(ct);
+        var result = new List<ListEntity>();
+        while (await reader.ReadAsync(ct))
+            result.Add(ReadList(reader));
+        return result;
+    }
+
+    public async Task<List<TagEntity>> GetTagsAsync(string listId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            SELECT t.id, t.name FROM tags t
+            JOIN list_tags lt ON lt.tag_id = t.id
+            WHERE lt.list_id = @list_id
+            """;
+        cmd.Parameters.AddWithValue("@list_id", listId);
+
+        await using var reader = await cmd.ExecuteReaderAsync(ct);
+        var result = new List<TagEntity>();
+        while (await reader.ReadAsync(ct))
+            result.Add(new TagEntity { Id = reader.GetInt64(0), Name = reader.GetString(1) });
+        return result;
+    }
+
+    public async Task AddTagAsync(string listId, long tagId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "INSERT OR IGNORE INTO list_tags (list_id, tag_id) VALUES (@list_id, @tag_id)";
+        cmd.Parameters.AddWithValue("@list_id", listId);
+        cmd.Parameters.AddWithValue("@tag_id", tagId);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task RemoveTagAsync(string listId, long tagId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "DELETE FROM list_tags WHERE list_id = @list_id AND tag_id = @tag_id";
+        cmd.Parameters.AddWithValue("@list_id", listId);
+        cmd.Parameters.AddWithValue("@tag_id", tagId);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    private static ListEntity ReadList(SqliteDataReader reader) => new()
+    {
+        Id = reader.GetString(0),
+        Name = reader.GetString(1),
+        CreatedAt = DateTime.Parse(reader.GetString(2)),
+        WorkingDir = reader.IsDBNull(3) ? null : reader.GetString(3),
+        DefaultCommitType = reader.GetString(4),
+    };
+}
diff --git a/src/ClaudeDo.Data/Repositories/TagRepository.cs b/src/ClaudeDo.Data/Repositories/TagRepository.cs
new file mode 100644
index 0000000..d73d9b7
--- /dev/null
+++ b/src/ClaudeDo.Data/Repositories/TagRepository.cs
@@ -0,0 +1,33 @@
+using Microsoft.Data.Sqlite;
+
+namespace ClaudeDo.Data.Repositories;
+
+public sealed class TagRepository
+{
+    private readonly SqliteConnectionFactory _factory;
+
+    public TagRepository(SqliteConnectionFactory factory) => _factory = factory;
+
+    public async Task<long> GetOrCreateAsync(string name, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        return await GetOrCreateAsync(conn, name, ct);
+    }
+
+    public static async Task<long> GetOrCreateAsync(SqliteConnection conn, string name, CancellationToken ct = default)
+    {
+        await using var sel = conn.CreateCommand();
+        sel.CommandText = "SELECT id FROM tags WHERE name = @name";
+        sel.Parameters.AddWithValue("@name", name);
+
+        var existing = await sel.ExecuteScalarAsync(ct);
+        if (existing is not null)
+            return (long)existing;
+
+        await using var ins = conn.CreateCommand();
+        ins.CommandText = "INSERT INTO tags (name) VALUES (@name) RETURNING id";
+        ins.Parameters.AddWithValue("@name", name);
+
+        return (long)(await ins.ExecuteScalarAsync(ct))!;
+    }
+}
diff --git a/src/ClaudeDo.Data/Repositories/TaskRepository.cs b/src/ClaudeDo.Data/Repositories/TaskRepository.cs
new file mode 100644
index 0000000..5bbb404
--- /dev/null
+++ b/src/ClaudeDo.Data/Repositories/TaskRepository.cs
@@ -0,0 +1,289 @@
+using ClaudeDo.Data.Models;
+using Microsoft.Data.Sqlite;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Data.Repositories;
+
+public sealed class TaskRepository
+{
+    private readonly SqliteConnectionFactory _factory;
+
+    public TaskRepository(SqliteConnectionFactory factory) => _factory = factory;
+
+    #region Status mapping
+
+    private static string ToDb(TaskStatus s) => s switch
+    {
+        TaskStatus.Manual => "manual",
+        TaskStatus.Queued => "queued",
+        TaskStatus.Running => "running",
+        TaskStatus.Done => "done",
+        TaskStatus.Failed => "failed",
+        _ => throw new ArgumentOutOfRangeException(nameof(s)),
+    };
+
+    private static TaskStatus FromDb(string s) => s switch
+    {
+        "manual" => TaskStatus.Manual,
+        "queued" => TaskStatus.Queued,
+        "running" => TaskStatus.Running,
+        "done" => TaskStatus.Done,
+        "failed" => TaskStatus.Failed,
+        _ => throw new ArgumentOutOfRangeException(nameof(s)),
+    };
+
+    #endregion
+
+    #region CRUD
+
+    public async Task AddAsync(TaskEntity entity, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            INSERT INTO tasks (id, list_id, title, description, status, scheduled_for,
+                               result, log_path, created_at, started_at, finished_at, commit_type)
+            VALUES (@id, @list_id, @title, @description, @status, @scheduled_for,
+                    @result, @log_path, @created_at, @started_at, @finished_at, @commit_type)
+            """;
+        BindTask(cmd, entity);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task UpdateAsync(TaskEntity entity, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            UPDATE tasks SET list_id = @list_id, title = @title, description = @description,
+                             status = @status, scheduled_for = @scheduled_for, result = @result,
+                             log_path = @log_path, started_at = @started_at,
+                             finished_at = @finished_at, commit_type = @commit_type
+            WHERE id = @id
+            """;
+        BindTask(cmd, entity);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task DeleteAsync(string taskId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "DELETE FROM tasks WHERE id = @id";
+        cmd.Parameters.AddWithValue("@id", taskId);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task<TaskEntity?> GetByIdAsync(string taskId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "SELECT id, list_id, title, description, status, scheduled_for, result, log_path, created_at, started_at, finished_at, commit_type FROM tasks WHERE id = @id";
+        cmd.Parameters.AddWithValue("@id", taskId);
+
+        await using var reader = await cmd.ExecuteReaderAsync(ct);
+        if (!await reader.ReadAsync(ct)) return null;
+        return ReadTask(reader);
+    }
+
+    public async Task<List<TaskEntity>> GetByListAsync(string listId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "SELECT id, list_id, title, description, status, scheduled_for, result, log_path, created_at, started_at, finished_at, commit_type FROM tasks WHERE list_id = @list_id ORDER BY created_at";
+        cmd.Parameters.AddWithValue("@list_id", listId);
+
+        await using var reader = await cmd.ExecuteReaderAsync(ct);
+        var result = new List<TaskEntity>();
+        while (await reader.ReadAsync(ct))
+            result.Add(ReadTask(reader));
+        return result;
+    }
+
+    #endregion
+
+    #region Tag junction
+
+    public async Task<List<TagEntity>> GetTagsAsync(string taskId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            SELECT t.id, t.name FROM tags t
+            JOIN task_tags tt ON tt.tag_id = t.id
+            WHERE tt.task_id = @task_id
+            """;
+        cmd.Parameters.AddWithValue("@task_id", taskId);
+
+        await using var reader = await cmd.ExecuteReaderAsync(ct);
+        var result = new List<TagEntity>();
+        while (await reader.ReadAsync(ct))
+            result.Add(new TagEntity { Id = reader.GetInt64(0), Name = reader.GetString(1) });
+        return result;
+    }
+
+    public async Task AddTagAsync(string taskId, long tagId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "INSERT OR IGNORE INTO task_tags (task_id, tag_id) VALUES (@task_id, @tag_id)";
+        cmd.Parameters.AddWithValue("@task_id", taskId);
+        cmd.Parameters.AddWithValue("@tag_id", tagId);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task RemoveTagAsync(string taskId, long tagId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "DELETE FROM task_tags WHERE task_id = @task_id AND tag_id = @tag_id";
+        cmd.Parameters.AddWithValue("@task_id", taskId);
+        cmd.Parameters.AddWithValue("@tag_id", tagId);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task<List<TagEntity>> GetEffectiveTagsAsync(string taskId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            SELECT DISTINCT t.id, t.name FROM tags t
+            WHERE t.id IN (
+                SELECT tag_id FROM task_tags WHERE task_id = @task_id
+                UNION
+                SELECT lt.tag_id FROM list_tags lt
+                JOIN tasks tk ON tk.list_id = lt.list_id
+                WHERE tk.id = @task_id
+            )
+            """;
+        cmd.Parameters.AddWithValue("@task_id", taskId);
+
+        await using var reader = await cmd.ExecuteReaderAsync(ct);
+        var result = new List<TagEntity>();
+        while (await reader.ReadAsync(ct))
+            result.Add(new TagEntity { Id = reader.GetInt64(0), Name = reader.GetString(1) });
+        return result;
+    }
+
+    #endregion
+
+    #region Queue selection
+
+    public async Task<TaskEntity?> GetNextQueuedAgentTaskAsync(DateTime now, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            SELECT t.id, t.list_id, t.title, t.description, t.status, t.scheduled_for,
+                   t.result, t.log_path, t.created_at, t.started_at, t.finished_at, t.commit_type
+            FROM tasks t
+            WHERE t.status = 'queued'
+              AND (t.scheduled_for IS NULL OR t.scheduled_for <= @now)
+              AND EXISTS (
+                  SELECT 1 FROM task_tags tt
+                  JOIN tags tg ON tg.id = tt.tag_id
+                  WHERE tt.task_id = t.id AND tg.name = 'agent'
+                  UNION
+                  SELECT 1 FROM list_tags lt
+                  JOIN tags tg ON tg.id = lt.tag_id
+                  WHERE lt.list_id = t.list_id AND tg.name = 'agent'
+              )
+            ORDER BY t.created_at ASC
+            LIMIT 1
+            """;
+        cmd.Parameters.AddWithValue("@now", now.ToString("o"));
+
+        await using var reader = await cmd.ExecuteReaderAsync(ct);
+        if (!await reader.ReadAsync(ct)) return null;
+        return ReadTask(reader);
+    }
+
+    #endregion
+
+    #region Transitions
+
+    public async Task MarkRunningAsync(string taskId, DateTime startedAt, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "UPDATE tasks SET status = 'running', started_at = @started_at WHERE id = @id";
+        cmd.Parameters.AddWithValue("@id", taskId);
+        cmd.Parameters.AddWithValue("@started_at", startedAt.ToString("o"));
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task MarkDoneAsync(string taskId, DateTime finishedAt, string? result, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "UPDATE tasks SET status = 'done', finished_at = @finished_at, result = @result WHERE id = @id";
+        cmd.Parameters.AddWithValue("@id", taskId);
+        cmd.Parameters.AddWithValue("@finished_at", finishedAt.ToString("o"));
+        cmd.Parameters.AddWithValue("@result", (object?)result ?? DBNull.Value);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task MarkFailedAsync(string taskId, DateTime finishedAt, string? errorMarkdown, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "UPDATE tasks SET status = 'failed', finished_at = @finished_at, result = @result WHERE id = @id";
+        cmd.Parameters.AddWithValue("@id", taskId);
+        cmd.Parameters.AddWithValue("@finished_at", finishedAt.ToString("o"));
+        cmd.Parameters.AddWithValue("@result", (object?)errorMarkdown ?? DBNull.Value);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task<int> FlipAllRunningToFailedAsync(string reason, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            UPDATE tasks SET status = 'failed',
+                             finished_at = @now,
+                             result = '[stale] ' || @reason
+            WHERE status = 'running'
+            """;
+        cmd.Parameters.AddWithValue("@now", DateTime.UtcNow.ToString("o"));
+        cmd.Parameters.AddWithValue("@reason", reason);
+        return await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    #endregion
+
+    #region Helpers
+
+    private static void BindTask(SqliteCommand cmd, TaskEntity e)
+    {
+        cmd.Parameters.AddWithValue("@id", e.Id);
+        cmd.Parameters.AddWithValue("@list_id", e.ListId);
+        cmd.Parameters.AddWithValue("@title", e.Title);
+        cmd.Parameters.AddWithValue("@description", (object?)e.Description ?? DBNull.Value);
+        cmd.Parameters.AddWithValue("@status", ToDb(e.Status));
+        cmd.Parameters.AddWithValue("@scheduled_for", e.ScheduledFor.HasValue ? e.ScheduledFor.Value.ToString("o") : DBNull.Value);
+        cmd.Parameters.AddWithValue("@result", (object?)e.Result ?? DBNull.Value);
+        cmd.Parameters.AddWithValue("@log_path", (object?)e.LogPath ?? DBNull.Value);
+        cmd.Parameters.AddWithValue("@created_at", e.CreatedAt.ToString("o"));
+        cmd.Parameters.AddWithValue("@started_at", e.StartedAt.HasValue ? e.StartedAt.Value.ToString("o") : DBNull.Value);
+        cmd.Parameters.AddWithValue("@finished_at", e.FinishedAt.HasValue ? e.FinishedAt.Value.ToString("o") : DBNull.Value);
+        cmd.Parameters.AddWithValue("@commit_type", e.CommitType);
+    }
+
+    private static TaskEntity ReadTask(SqliteDataReader r) => new()
+    {
+        Id = r.GetString(0),
+        ListId = r.GetString(1),
+        Title = r.GetString(2),
+        Description = r.IsDBNull(3) ? null : r.GetString(3),
+        Status = FromDb(r.GetString(4)),
+        ScheduledFor = r.IsDBNull(5) ? null : DateTime.Parse(r.GetString(5)),
+        Result = r.IsDBNull(6) ? null : r.GetString(6),
+        LogPath = r.IsDBNull(7) ? null : r.GetString(7),
+        CreatedAt = DateTime.Parse(r.GetString(8)),
+        StartedAt = r.IsDBNull(9) ? null : DateTime.Parse(r.GetString(9)),
+        FinishedAt = r.IsDBNull(10) ? null : DateTime.Parse(r.GetString(10)),
+        CommitType = r.GetString(11),
+    };
+
+    #endregion
+}
diff --git a/src/ClaudeDo.Data/Repositories/WorktreeRepository.cs b/src/ClaudeDo.Data/Repositories/WorktreeRepository.cs
new file mode 100644
index 0000000..ae96a54
--- /dev/null
+++ b/src/ClaudeDo.Data/Repositories/WorktreeRepository.cs
@@ -0,0 +1,102 @@
+using ClaudeDo.Data.Models;
+using Microsoft.Data.Sqlite;
+
+namespace ClaudeDo.Data.Repositories;
+
+public sealed class WorktreeRepository
+{
+    private readonly SqliteConnectionFactory _factory;
+
+    public WorktreeRepository(SqliteConnectionFactory factory) => _factory = factory;
+
+    private static string ToDb(WorktreeState s) => s switch
+    {
+        WorktreeState.Active => "active",
+        WorktreeState.Merged => "merged",
+        WorktreeState.Discarded => "discarded",
+        WorktreeState.Kept => "kept",
+        _ => throw new ArgumentOutOfRangeException(nameof(s)),
+    };
+
+    private static WorktreeState FromDb(string s) => s switch
+    {
+        "active" => WorktreeState.Active,
+        "merged" => WorktreeState.Merged,
+        "discarded" => WorktreeState.Discarded,
+        "kept" => WorktreeState.Kept,
+        _ => throw new ArgumentOutOfRangeException(nameof(s)),
+    };
+
+    public async Task AddAsync(WorktreeEntity entity, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = """
+            INSERT INTO worktrees (task_id, path, branch_name, base_commit, head_commit, diff_stat, state, created_at)
+            VALUES (@task_id, @path, @branch_name, @base_commit, @head_commit, @diff_stat, @state, @created_at)
+            """;
+        cmd.Parameters.AddWithValue("@task_id", entity.TaskId);
+        cmd.Parameters.AddWithValue("@path", entity.Path);
+        cmd.Parameters.AddWithValue("@branch_name", entity.BranchName);
+        cmd.Parameters.AddWithValue("@base_commit", entity.BaseCommit);
+        cmd.Parameters.AddWithValue("@head_commit", (object?)entity.HeadCommit ?? DBNull.Value);
+        cmd.Parameters.AddWithValue("@diff_stat", (object?)entity.DiffStat ?? DBNull.Value);
+        cmd.Parameters.AddWithValue("@state", ToDb(entity.State));
+        cmd.Parameters.AddWithValue("@created_at", entity.CreatedAt.ToString("o"));
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task<WorktreeEntity?> GetByTaskIdAsync(string taskId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "SELECT task_id, path, branch_name, base_commit, head_commit, diff_stat, state, created_at FROM worktrees WHERE task_id = @task_id";
+        cmd.Parameters.AddWithValue("@task_id", taskId);
+
+        await using var reader = await cmd.ExecuteReaderAsync(ct);
+        if (!await reader.ReadAsync(ct)) return null;
+        return ReadWorktree(reader);
+    }
+
+    public async Task UpdateHeadAsync(string taskId, string headCommit, string? diffStat, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "UPDATE worktrees SET head_commit = @head_commit, diff_stat = @diff_stat WHERE task_id = @task_id";
+        cmd.Parameters.AddWithValue("@task_id", taskId);
+        cmd.Parameters.AddWithValue("@head_commit", headCommit);
+        cmd.Parameters.AddWithValue("@diff_stat", (object?)diffStat ?? DBNull.Value);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task SetStateAsync(string taskId, WorktreeState state, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "UPDATE worktrees SET state = @state WHERE task_id = @task_id";
+        cmd.Parameters.AddWithValue("@task_id", taskId);
+        cmd.Parameters.AddWithValue("@state", ToDb(state));
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    public async Task DeleteAsync(string taskId, CancellationToken ct = default)
+    {
+        await using var conn = _factory.Open();
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = "DELETE FROM worktrees WHERE task_id = @task_id";
+        cmd.Parameters.AddWithValue("@task_id", taskId);
+        await cmd.ExecuteNonQueryAsync(ct);
+    }
+
+    private static WorktreeEntity ReadWorktree(SqliteDataReader r) => new()
+    {
+        TaskId = r.GetString(0),
+        Path = r.GetString(1),
+        BranchName = r.GetString(2),
+        BaseCommit = r.GetString(3),
+        HeadCommit = r.IsDBNull(4) ? null : r.GetString(4),
+        DiffStat = r.IsDBNull(5) ? null : r.GetString(5),
+        State = FromDb(r.GetString(6)),
+        CreatedAt = DateTime.Parse(r.GetString(7)),
+    };
+}
diff --git a/src/ClaudeDo.Worker/Program.cs b/src/ClaudeDo.Worker/Program.cs
index 55386fb..a3e06ac 100644
--- a/src/ClaudeDo.Worker/Program.cs
+++ b/src/ClaudeDo.Worker/Program.cs
@@ -1,6 +1,8 @@
 using ClaudeDo.Data;
+using ClaudeDo.Data.Repositories;
 using ClaudeDo.Worker.Config;
 using ClaudeDo.Worker.Hub;
+using ClaudeDo.Worker.Services;
 
 var cfg = WorkerConfig.Load();
 
@@ -12,6 +14,11 @@ SchemaInitializer.Apply(dbFactory);
 
 builder.Services.AddSingleton(cfg);
 builder.Services.AddSingleton(dbFactory);
+builder.Services.AddSingleton<TagRepository>();
+builder.Services.AddSingleton<ListRepository>();
+builder.Services.AddSingleton<TaskRepository>();
+builder.Services.AddSingleton<WorktreeRepository>();
+builder.Services.AddHostedService<StaleTaskRecovery>();
 builder.Services.AddSignalR();
 
 // Loopback-only bind. Firewall is irrelevant for 127.0.0.1.
diff --git a/src/ClaudeDo.Worker/Services/StaleTaskRecovery.cs b/src/ClaudeDo.Worker/Services/StaleTaskRecovery.cs
new file mode 100644
index 0000000..aa43d66
--- /dev/null
+++ b/src/ClaudeDo.Worker/Services/StaleTaskRecovery.cs
@@ -0,0 +1,26 @@
+using ClaudeDo.Data.Repositories;
+
+namespace ClaudeDo.Worker.Services;
+
+public sealed class StaleTaskRecovery : IHostedService
+{
+    private readonly TaskRepository _tasks;
+    private readonly ILogger<StaleTaskRecovery> _logger;
+
+    public StaleTaskRecovery(TaskRepository tasks, ILogger<StaleTaskRecovery> logger)
+    {
+        _tasks = tasks;
+        _logger = logger;
+    }
+
+    public async Task StartAsync(CancellationToken cancellationToken)
+    {
+        var flipped = await _tasks.FlipAllRunningToFailedAsync("worker restart", cancellationToken);
+        if (flipped > 0)
+            _logger.LogWarning("Stale task recovery: flipped {Count} running task(s) to failed", flipped);
+        else
+            _logger.LogInformation("Stale task recovery: no stale tasks found");
+    }
+
+    public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;
+}
diff --git a/tests/ClaudeDo.Worker.Tests/ClaudeDo.Worker.Tests.csproj b/tests/ClaudeDo.Worker.Tests/ClaudeDo.Worker.Tests.csproj
index 21410a0..bfa12a3 100644
--- a/tests/ClaudeDo.Worker.Tests/ClaudeDo.Worker.Tests.csproj
+++ b/tests/ClaudeDo.Worker.Tests/ClaudeDo.Worker.Tests.csproj
@@ -11,6 +11,7 @@
 
   <ItemGroup>
     <PackageReference Include="coverlet.collector" Version="6.0.0" />
+    <PackageReference Include="Microsoft.Data.Sqlite" Version="8.0.11" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
     <PackageReference Include="xunit" Version="2.5.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.5.3" />
diff --git a/tests/ClaudeDo.Worker.Tests/Infrastructure/DbFixture.cs b/tests/ClaudeDo.Worker.Tests/Infrastructure/DbFixture.cs
new file mode 100644
index 0000000..ebd8ff5
--- /dev/null
+++ b/tests/ClaudeDo.Worker.Tests/Infrastructure/DbFixture.cs
@@ -0,0 +1,23 @@
+using ClaudeDo.Data;
+
+namespace ClaudeDo.Worker.Tests.Infrastructure;
+
+public sealed class DbFixture : IDisposable
+{
+    public string DbPath { get; }
+    public SqliteConnectionFactory Factory { get; }
+
+    public DbFixture()
+    {
+        DbPath = Path.Combine(Path.GetTempPath(), $"claudedo_test_{Guid.NewGuid():N}.db");
+        Factory = new SqliteConnectionFactory(DbPath);
+        SchemaInitializer.Apply(Factory);
+    }
+
+    public void Dispose()
+    {
+        try { File.Delete(DbPath); } catch { /* best effort */ }
+        try { File.Delete(DbPath + "-wal"); } catch { }
+        try { File.Delete(DbPath + "-shm"); } catch { }
+    }
+}
diff --git a/tests/ClaudeDo.Worker.Tests/Repositories/ListRepositoryTests.cs b/tests/ClaudeDo.Worker.Tests/Repositories/ListRepositoryTests.cs
new file mode 100644
index 0000000..f1e931d
--- /dev/null
+++ b/tests/ClaudeDo.Worker.Tests/Repositories/ListRepositoryTests.cs
@@ -0,0 +1,107 @@
+using ClaudeDo.Data.Models;
+using ClaudeDo.Data.Repositories;
+using ClaudeDo.Worker.Tests.Infrastructure;
+
+namespace ClaudeDo.Worker.Tests.Repositories;
+
+public sealed class ListRepositoryTests : IDisposable
+{
+    private readonly DbFixture _db = new();
+    private readonly ListRepository _lists;
+    private readonly TagRepository _tags;
+
+    public ListRepositoryTests()
+    {
+        _lists = new ListRepository(_db.Factory);
+        _tags = new TagRepository(_db.Factory);
+    }
+
+    public void Dispose() => _db.Dispose();
+
+    [Fact]
+    public async Task AddAsync_And_GetByIdAsync_Roundtrips()
+    {
+        var entity = new ListEntity
+        {
+            Id = Guid.NewGuid().ToString(),
+            Name = "Shopping",
+            CreatedAt = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc),
+            WorkingDir = @"C:\Repos\Test",
+            DefaultCommitType = "feat",
+        };
+
+        await _lists.AddAsync(entity);
+        var loaded = await _lists.GetByIdAsync(entity.Id);
+
+        Assert.NotNull(loaded);
+        Assert.Equal(entity.Id, loaded.Id);
+        Assert.Equal(entity.Name, loaded.Name);
+        Assert.Equal(entity.WorkingDir, loaded.WorkingDir);
+        Assert.Equal(entity.DefaultCommitType, loaded.DefaultCommitType);
+    }
+
+    [Fact]
+    public async Task UpdateAsync_Changes_Fields()
+    {
+        var entity = new ListEntity
+        {
+            Id = Guid.NewGuid().ToString(),
+            Name = "Original",
+            CreatedAt = DateTime.UtcNow,
+        };
+        await _lists.AddAsync(entity);
+
+        entity.Name = "Updated";
+        entity.WorkingDir = @"C:\New";
+        await _lists.UpdateAsync(entity);
+
+        var loaded = await _lists.GetByIdAsync(entity.Id);
+        Assert.Equal("Updated", loaded!.Name);
+        Assert.Equal(@"C:\New", loaded.WorkingDir);
+    }
+
+    [Fact]
+    public async Task DeleteAsync_Removes_List()
+    {
+        var entity = new ListEntity
+        {
+            Id = Guid.NewGuid().ToString(),
+            Name = "ToDelete",
+            CreatedAt = DateTime.UtcNow,
+        };
+        await _lists.AddAsync(entity);
+        await _lists.DeleteAsync(entity.Id);
+
+        var loaded = await _lists.GetByIdAsync(entity.Id);
+        Assert.Null(loaded);
+    }
+
+    [Fact]
+    public async Task GetAllAsync_Returns_All_Lists()
+    {
+        var a = new ListEntity { Id = Guid.NewGuid().ToString(), Name = "A", CreatedAt = DateTime.UtcNow.AddMinutes(-1) };
+        var b = new ListEntity { Id = Guid.NewGuid().ToString(), Name = "B", CreatedAt = DateTime.UtcNow };
+        await _lists.AddAsync(a);
+        await _lists.AddAsync(b);
+
+        var all = await _lists.GetAllAsync();
+        Assert.True(all.Count >= 2);
+    }
+
+    [Fact]
+    public async Task TagJunction_AddAndRemove()
+    {
+        var listId = Guid.NewGuid().ToString();
+        await _lists.AddAsync(new ListEntity { Id = listId, Name = "Tagged", CreatedAt = DateTime.UtcNow });
+        var tagId = await _tags.GetOrCreateAsync("agent");
+
+        await _lists.AddTagAsync(listId, tagId);
+        var tags = await _lists.GetTagsAsync(listId);
+        Assert.Single(tags);
+        Assert.Equal("agent", tags[0].Name);
+
+        await _lists.RemoveTagAsync(listId, tagId);
+        tags = await _lists.GetTagsAsync(listId);
+        Assert.Empty(tags);
+    }
+}
diff --git a/tests/ClaudeDo.Worker.Tests/Repositories/TaskRepositoryTests.cs b/tests/ClaudeDo.Worker.Tests/Repositories/TaskRepositoryTests.cs
new file mode 100644
index 0000000..e99c376
--- /dev/null
+++ b/tests/ClaudeDo.Worker.Tests/Repositories/TaskRepositoryTests.cs
@@ -0,0 +1,217 @@
+using ClaudeDo.Data.Models;
+using ClaudeDo.Data.Repositories;
+using ClaudeDo.Worker.Tests.Infrastructure;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Worker.Tests.Repositories;
+
+public sealed class TaskRepositoryTests : IDisposable
+{
+    private readonly DbFixture _db = new();
+    private readonly TaskRepository _tasks;
+    private readonly ListRepository _lists;
+    private readonly TagRepository _tags;
+
+    public TaskRepositoryTests()
+    {
+        _tasks = new TaskRepository(_db.Factory);
+        _lists = new ListRepository(_db.Factory);
+        _tags = new TagRepository(_db.Factory);
+    }
+
+    public void Dispose() => _db.Dispose();
+
+    private async Task<string> CreateListAsync(string? id = null)
+    {
+        var listId = id ?? Guid.NewGuid().ToString();
+        await _lists.AddAsync(new ListEntity
+        {
+            Id = listId,
+            Name = "Test List",
+            CreatedAt = DateTime.UtcNow,
+        });
+        return listId;
+    }
+
+    private TaskEntity MakeTask(string listId, TaskStatus status = TaskStatus.Queued, DateTime? createdAt = null, DateTime? scheduledFor = null) => new()
+    {
+        Id = Guid.NewGuid().ToString(),
+        ListId = listId,
+        Title = "Test Task",
+        Description = "A description",
+        Status = status,
+        ScheduledFor = scheduledFor,
+        CreatedAt = createdAt ?? DateTime.UtcNow,
+        CommitType = "feat",
+    };
+
+    [Fact]
+    public async Task AddAsync_Roundtrips_AllFields()
+    {
+        var listId = await CreateListAsync();
+        var entity = new TaskEntity
+        {
+            Id = Guid.NewGuid().ToString(),
+            ListId = listId,
+            Title = "My Task",
+            Description = "Desc",
+            Status = TaskStatus.Queued,
+            ScheduledFor = new DateTime(2026, 1, 1, 12, 0, 0, DateTimeKind.Utc),
+            Result = "some result",
+            LogPath = "/tmp/log.ndjson",
+            CreatedAt = new DateTime(2026, 1, 1, 0, 0, 0, DateTimeKind.Utc),
+            StartedAt = new DateTime(2026, 1, 1, 1, 0, 0, DateTimeKind.Utc),
+            FinishedAt = new DateTime(2026, 1, 1, 2, 0, 0, DateTimeKind.Utc),
+            CommitType = "feat",
+        };
+
+        await _tasks.AddAsync(entity);
+        var loaded = await _tasks.GetByIdAsync(entity.Id);
+
+        Assert.NotNull(loaded);
+        Assert.Equal(entity.Id, loaded.Id);
+        Assert.Equal(entity.ListId, loaded.ListId);
+        Assert.Equal(entity.Title, loaded.Title);
+        Assert.Equal(entity.Description, loaded.Description);
+        Assert.Equal(entity.Status, loaded.Status);
+        Assert.Equal(entity.ScheduledFor!.Value.Date, loaded.ScheduledFor!.Value.Date);
+        Assert.Equal(entity.Result, loaded.Result);
+        Assert.Equal(entity.LogPath, loaded.LogPath);
+        Assert.Equal(entity.CommitType, loaded.CommitType);
+    }
+
+    [Fact]
+    public async Task GetNextQueuedAgentTaskAsync_Returns_OldestWithAgentTag_ViaTaskTag()
+    {
+        var listId = await CreateListAsync();
+        var agentTagId = await _tags.GetOrCreateAsync("agent");
+
+        var older = MakeTask(listId, createdAt: DateTime.UtcNow.AddMinutes(-10));
+        var newer = MakeTask(listId, createdAt: DateTime.UtcNow);
+        await _tasks.AddAsync(older);
+        await _tasks.AddAsync(newer);
+        await _tasks.AddTagAsync(older.Id, agentTagId);
+        await _tasks.AddTagAsync(newer.Id, agentTagId);
+
+        var picked = await _tasks.GetNextQueuedAgentTaskAsync(DateTime.UtcNow);
+        Assert.NotNull(picked);
+        Assert.Equal(older.Id, picked.Id);
+    }
+
+    [Fact]
+    public async Task GetNextQueuedAgentTaskAsync_Returns_TaskWithAgentTag_ViaListTag()
+    {
+        var listId = await CreateListAsync();
+        var agentTagId = await _tags.GetOrCreateAsync("agent");
+        await _lists.AddTagAsync(listId, agentTagId);
+
+        var task = MakeTask(listId);
+        await _tasks.AddAsync(task);
+
+        var picked = await _tasks.GetNextQueuedAgentTaskAsync(DateTime.UtcNow);
+        Assert.NotNull(picked);
+        Assert.Equal(task.Id, picked.Id);
+    }
+
+    [Fact]
+    public async Task GetNextQueuedAgentTaskAsync_ReturnsNull_WhenNoAgentTag()
+    {
+        var listId = await CreateListAsync();
+        var task = MakeTask(listId);
+        await _tasks.AddAsync(task);
+
+        var picked = await _tasks.GetNextQueuedAgentTaskAsync(DateTime.UtcNow);
+        Assert.Null(picked);
+    }
+
+    [Fact]
+    public async Task GetNextQueuedAgentTaskAsync_Skips_FutureScheduledFor()
+    {
+        var listId = await CreateListAsync();
+        var agentTagId = await _tags.GetOrCreateAsync("agent");
+
+        var task = MakeTask(listId, scheduledFor: DateTime.UtcNow.AddHours(1));
+        await _tasks.AddAsync(task);
+        await _tasks.AddTagAsync(task.Id, agentTagId);
+
+        var picked = await _tasks.GetNextQueuedAgentTaskAsync(DateTime.UtcNow);
+        Assert.Null(picked);
+    }
+
+    [Fact]
+    public async Task Transitions_MarkRunning_ThenMarkDone()
+    {
+        var listId = await CreateListAsync();
+        var task = MakeTask(listId);
+        await _tasks.AddAsync(task);
+
+        var startedAt = DateTime.UtcNow;
+        await _tasks.MarkRunningAsync(task.Id, startedAt);
+        var running = await _tasks.GetByIdAsync(task.Id);
+        Assert.Equal(TaskStatus.Running, running!.Status);
+        Assert.NotNull(running.StartedAt);
+
+        var finishedAt = DateTime.UtcNow;
+        await _tasks.MarkDoneAsync(task.Id, finishedAt, "All good");
+        var done = await _tasks.GetByIdAsync(task.Id);
+        Assert.Equal(TaskStatus.Done, done!.Status);
+        Assert.Equal("All good", done.Result);
+        Assert.NotNull(done.FinishedAt);
+    }
+
+    [Fact]
+    public async Task FlipAllRunningToFailedAsync_FlipsOnlyRunningRows()
+    {
+        var listId = await CreateListAsync();
+        var running1 = MakeTask(listId, status: TaskStatus.Running);
+        var running2 = MakeTask(listId, status: TaskStatus.Running);
+        var queued = MakeTask(listId, status: TaskStatus.Queued);
+        var done = MakeTask(listId, status: TaskStatus.Done);
+
+        await _tasks.AddAsync(running1);
+        await _tasks.AddAsync(running2);
+        await _tasks.AddAsync(queued);
+        await _tasks.AddAsync(done);
+
+        var flipped = await _tasks.FlipAllRunningToFailedAsync("worker restart");
+
+        Assert.Equal(2, flipped);
+
+        var r1 = await _tasks.GetByIdAsync(running1.Id);
+        Assert.Equal(TaskStatus.Failed, r1!.Status);
+        Assert.StartsWith("[stale] ", r1.Result);
+
+        var r2 = await _tasks.GetByIdAsync(running2.Id);
+        Assert.Equal(TaskStatus.Failed, r2!.Status);
+
+        var q = await _tasks.GetByIdAsync(queued.Id);
+        Assert.Equal(TaskStatus.Queued, q!.Status);
+
+        var d = await _tasks.GetByIdAsync(done.Id);
+        Assert.Equal(TaskStatus.Done, d!.Status);
+    }
+
+    [Fact]
+    public async Task GetEffectiveTagsAsync_Returns_Union_Of_ListTags_And_TaskTags()
+    {
+        var listId = await CreateListAsync();
+        var agentTagId = await _tags.GetOrCreateAsync("agent");
+        var manualTagId = await _tags.GetOrCreateAsync("manual");
+        var codeTagId = await TagRepository.GetOrCreateAsync(_db.Factory.Open(), "code");
+
+        await _lists.AddTagAsync(listId, agentTagId);
+
+        var task = MakeTask(listId);
+        await _tasks.AddAsync(task);
+        await _tasks.AddTagAsync(task.Id, manualTagId);
+        await _tasks.AddTagAsync(task.Id, codeTagId);
+
+        var effective = await _tasks.GetEffectiveTagsAsync(task.Id);
+        var names = effective.Select(t => t.Name).OrderBy(n => n).ToList();
+
+        Assert.Equal(3, names.Count);
+        Assert.Contains("agent", names);
+        Assert.Contains("code", names);
+        Assert.Contains("manual", names);
+    }
+}
diff --git a/tests/ClaudeDo.Worker.Tests/Services/StaleTaskRecoveryTests.cs b/tests/ClaudeDo.Worker.Tests/Services/StaleTaskRecoveryTests.cs
new file mode 100644
index 0000000..20d54ca
--- /dev/null
+++ b/tests/ClaudeDo.Worker.Tests/Services/StaleTaskRecoveryTests.cs
@@ -0,0 +1,60 @@
+using ClaudeDo.Data.Models;
+using ClaudeDo.Data.Repositories;
+using ClaudeDo.Worker.Services;
+using ClaudeDo.Worker.Tests.Infrastructure;
+using Microsoft.Extensions.Logging.Abstractions;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Worker.Tests.Services;
+
+public sealed class StaleTaskRecoveryTests : IDisposable
+{
+    private readonly DbFixture _db = new();
+    private readonly TaskRepository _tasks;
+    private readonly ListRepository _lists;
+
+    public StaleTaskRecoveryTests()
+    {
+        _tasks = new TaskRepository(_db.Factory);
+        _lists = new ListRepository(_db.Factory);
+    }
+
+    public void Dispose() => _db.Dispose();
+
+    [Fact]
+    public async Task StartAsync_Flips_Running_Tasks_To_Failed()
+    {
+        var listId = Guid.NewGuid().ToString();
+        await _lists.AddAsync(new ListEntity { Id = listId, Name = "Test", CreatedAt = DateTime.UtcNow });
+
+        var running = new TaskEntity
+        {
+            Id = Guid.NewGuid().ToString(),
+            ListId = listId,
+            Title = "Running task",
+            Status = TaskStatus.Running,
+            CreatedAt = DateTime.UtcNow,
+        };
+        var queued = new TaskEntity
+        {
+            Id = Guid.NewGuid().ToString(),
+            ListId = listId,
+            Title = "Queued task",
+            Status = TaskStatus.Queued,
+            CreatedAt = DateTime.UtcNow,
+        };
+
+        await _tasks.AddAsync(running);
+        await _tasks.AddAsync(queued);
+
+        var recovery = new StaleTaskRecovery(_tasks, NullLogger<StaleTaskRecovery>.Instance);
+        await recovery.StartAsync(CancellationToken.None);
+
+        var r = await _tasks.GetByIdAsync(running.Id);
+        Assert.Equal(TaskStatus.Failed, r!.Status);
+        Assert.StartsWith("[stale] ", r.Result);
+
+        var q = await _tasks.GetByIdAsync(queued.Id);
+        Assert.Equal(TaskStatus.Queued, q!.Status);
+    }
+}