M1: Identity & access — members, RBAC, JWT auth, invitations

Adds the access foundation everything else enforces against.

SharedKernel (shared access contracts, no Identity dependency for consumers):
- ScopeRef/ScopeType, RoleType, Capability, AccessPolicy (role x capability matrix),
  ICurrentUser, IPermissionService (scope-chain evaluation).

Identity module:
- Member, Membership, Invitation entities; internal IdentityDbContext (schema
  "identity") + InitialIdentity migration; design-time factory.
- JWT auth (HS256) issuing membership claims; PasswordHasher<Member>; CurrentUser
  (claims -> ICurrentUser) and PermissionService implementations.
- Public IMemberDirectory contract for other modules to resolve member display info.
- Endpoints: POST /bootstrap (first owner), /auth/login, GET /me, POST /invitations,
  POST /invitations/accept. Owner-only actions enforced via IPermissionService.
- Web host wires UseAuthentication/UseAuthorization and string-enum JSON.

Verified: build green; ArchitectureTests 8/8 (Identity references only SharedKernel);
IntegrationTests 11/11 incl. a new end-to-end flow — bootstrap -> login -> /me ->
invite -> accept -> login as invitee, and a Member is 403'd from inviting.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/Hosts/TeamUp.Web/Program.cs

@@ -1,3 +1,4 @@
+using System.Text.Json.Serialization;
 using OpenTelemetry.Trace;
 using Serilog;
 using TeamUp.Bootstrap;
@@ -12,6 +13,10 @@ builder.Host.UseSerilog((context, services, configuration) => configuration
 
 builder.Services.AddOpenApi();
 
+// Bind/serialize enums as strings across the API (e.g. ScopeType "Organization", RoleType "Member").
+builder.Services.ConfigureHttpJsonOptions(options =>
+    options.SerializerOptions.Converters.Add(new JsonStringEnumConverter()));
+
 builder.Services.AddTeamUpObservability(
     builder.Configuration,
     serviceName: "teamup-web",
@@ -42,6 +47,9 @@ app.UseSerilogRequestLogging();
 app.UseDefaultFiles();
 app.UseStaticFiles();
 
+app.UseAuthentication();
+app.UseAuthorization();
+
 app.MapHealthChecks("/health");
 app.MapTeamUpModules();
 

src/Hosts/TeamUp.Web/appsettings.json

@@ -5,6 +5,12 @@
   "Database": {
     "ApplyMigrationsOnStartup": false
   },
+  "Jwt": {
+    "Secret": "dev-only-teamup-jwt-signing-secret-change-in-production-0123456789",
+    "Issuer": "teamup",
+    "Audience": "teamup",
+    "ExpiryMinutes": 480
+  },
   "OpenTelemetry": {
     "OtlpEndpoint": ""
   },

src/Hosts/TeamUp.Worker/appsettings.json

@@ -5,6 +5,12 @@
   "Database": {
     "ApplyMigrationsOnStartup": false
   },
+  "Jwt": {
+    "Secret": "dev-only-teamup-jwt-signing-secret-change-in-production-0123456789",
+    "Issuer": "teamup",
+    "Audience": "teamup",
+    "ExpiryMinutes": 480
+  },
   "OpenTelemetry": {
     "OtlpEndpoint": ""
   },

src/Modules/TeamUp.Modules.Identity/Access/CurrentUser.cs

@@ -0,0 +1,52 @@
+using System.Security.Claims;
+using Microsoft.AspNetCore.Http;
+using Microsoft.IdentityModel.JsonWebTokens;
+using TeamUp.Modules.Identity.Auth;
+using TeamUp.SharedKernel.Access;
+
+namespace TeamUp.Modules.Identity.Access;
+
+/// <summary>
+/// Resolves <see cref="ICurrentUser"/> from the request's JWT claims. JWT bearer is configured with
+/// MapInboundClaims=false, so claim names stay raw ("sub", "email", "membership"). In the worker
+/// (no HttpContext) this reports unauthenticated.
+/// </summary>
+internal sealed class CurrentUser(IHttpContextAccessor accessor) : ICurrentUser
+{
+    private ClaimsPrincipal? Principal => accessor.HttpContext?.User;
+
+    public bool IsAuthenticated => Principal?.Identity?.IsAuthenticated == true;
+
+    public Guid MemberId =>
+        Guid.TryParse(Principal?.FindFirstValue(JwtRegisteredClaimNames.Sub), out var id)
+            ? id
+            : throw new InvalidOperationException("No authenticated member on the current request.");
+
+    public string Email => Principal?.FindFirstValue(JwtRegisteredClaimNames.Email) ?? string.Empty;
+
+    public IReadOnlyList<ScopedRole> Memberships
+    {
+        get
+        {
+            if (Principal is null)
+            {
+                return [];
+            }
+
+            var memberships = new List<ScopedRole>();
+            foreach (var claim in Principal.FindAll(JwtTokenService.MembershipClaim))
+            {
+                var parts = claim.Value.Split(':');
+                if (parts.Length == 3
+                    && Enum.TryParse<ScopeType>(parts[0], out var scopeType)
+                    && Guid.TryParse(parts[1], out var scopeId)
+                    && Enum.TryParse<RoleType>(parts[2], out var role))
+                {
+                    memberships.Add(new ScopedRole(new ScopeRef(scopeType, scopeId), role));
+                }
+            }
+
+            return memberships;
+        }
+    }
+}

src/Modules/TeamUp.Modules.Identity/Access/PermissionService.cs

@@ -0,0 +1,29 @@
+using TeamUp.SharedKernel.Access;
+
+namespace TeamUp.Modules.Identity.Access;
+
+/// <summary>
+/// Default <see cref="IPermissionService"/>: the current user has a capability if any of their
+/// memberships sits on a scope in the supplied chain and that role permits the capability.
+/// </summary>
+internal sealed class PermissionService(ICurrentUser currentUser) : IPermissionService
+{
+    public bool Has(Capability capability, params ScopeRef[] scopeChain)
+    {
+        if (!currentUser.IsAuthenticated || scopeChain.Length == 0)
+        {
+            return false;
+        }
+
+        foreach (var membership in currentUser.Memberships)
+        {
+            if (Array.IndexOf(scopeChain, membership.Scope) >= 0
+                && AccessPolicy.Permits(membership.Role, capability))
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}

src/Modules/TeamUp.Modules.Identity/Auth/JwtOptions.cs

@@ -0,0 +1,11 @@
+namespace TeamUp.Modules.Identity.Auth;
+
+internal sealed class JwtOptions
+{
+    public const string SectionName = "Jwt";
+
+    public string Secret { get; set; } = string.Empty;
+    public string Issuer { get; set; } = "teamup";
+    public string Audience { get; set; } = "teamup";
+    public int ExpiryMinutes { get; set; } = 480;
+}

src/Modules/TeamUp.Modules.Identity/Auth/JwtTokenService.cs

@@ -0,0 +1,47 @@
+using System.Security.Claims;
+using System.Text;
+using Microsoft.Extensions.Options;
+using Microsoft.IdentityModel.JsonWebTokens;
+using Microsoft.IdentityModel.Tokens;
+using TeamUp.Modules.Identity.Domain;
+
+namespace TeamUp.Modules.Identity.Auth;
+
+/// <summary>Issues signed JWTs carrying the member id, email, and one claim per membership.</summary>
+internal sealed class JwtTokenService(IOptions<JwtOptions> options, TimeProvider timeProvider)
+{
+    public const string MembershipClaim = "membership";
+
+    private readonly JwtOptions _options = options.Value;
+
+    public string Issue(Member member, IReadOnlyList<Membership> memberships)
+    {
+        var now = timeProvider.GetUtcNow();
+
+        var claims = new List<Claim>
+        {
+            new(JwtRegisteredClaimNames.Sub, member.Id.ToString()),
+            new(JwtRegisteredClaimNames.Email, member.Email),
+            new("name", member.DisplayName),
+        };
+
+        foreach (var membership in memberships)
+        {
+            claims.Add(new Claim(MembershipClaim, $"{membership.ScopeType}:{membership.ScopeId}:{membership.Role}"));
+        }
+
+        var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_options.Secret));
+        var descriptor = new SecurityTokenDescriptor
+        {
+            Issuer = _options.Issuer,
+            Audience = _options.Audience,
+            Subject = new ClaimsIdentity(claims),
+            IssuedAt = now.UtcDateTime,
+            NotBefore = now.UtcDateTime,
+            Expires = now.AddMinutes(_options.ExpiryMinutes).UtcDateTime,
+            SigningCredentials = new SigningCredentials(key, SecurityAlgorithms.HmacSha256),
+        };
+
+        return new JsonWebTokenHandler().CreateToken(descriptor);
+    }
+}

src/Modules/TeamUp.Modules.Identity/Contracts/IMemberDirectory.cs

@@ -0,0 +1,17 @@
+namespace TeamUp.Modules.Identity.Contracts;
+
+/// <summary>Public, non-sensitive member info other modules may display (e.g. board assignees).</summary>
+public sealed record MemberSummary(Guid Id, string Email, string DisplayName);
+
+/// <summary>
+/// The Identity module's public surface for resolving member display info by id. Other modules
+/// depend on this interface — never on Identity's entities or DbContext.
+/// </summary>
+public interface IMemberDirectory
+{
+    Task<MemberSummary?> FindByIdAsync(Guid memberId, CancellationToken cancellationToken = default);
+
+    Task<IReadOnlyDictionary<Guid, MemberSummary>> GetByIdsAsync(
+        IReadOnlyCollection<Guid> memberIds,
+        CancellationToken cancellationToken = default);
+}

src/Modules/TeamUp.Modules.Identity/Domain/Invitation.cs

@@ -0,0 +1,55 @@
+using TeamUp.SharedKernel.Access;
+using TeamUp.SharedKernel.Domain;
+
+namespace TeamUp.Modules.Identity.Domain;
+
+internal enum InvitationStatus
+{
+    Pending,
+    Accepted,
+    Revoked,
+}
+
+/// <summary>An invitation to join at a scope+role. Accepting it creates the member + membership.</summary>
+internal sealed class Invitation : Entity
+{
+    public string Email { get; private set; } = null!;
+    public ScopeType ScopeType { get; private set; }
+    public Guid ScopeId { get; private set; }
+    public RoleType Role { get; private set; }
+    public string Token { get; private set; } = null!;
+    public InvitationStatus Status { get; private set; }
+    public Guid InvitedByMemberId { get; private set; }
+    public DateTimeOffset CreatedAtUtc { get; private set; }
+    public DateTimeOffset? AcceptedAtUtc { get; private set; }
+
+    private Invitation()
+    {
+    }
+
+    public Invitation(
+        string email,
+        ScopeRef scope,
+        RoleType role,
+        string token,
+        Guid invitedByMemberId,
+        DateTimeOffset createdAtUtc)
+    {
+        Email = email;
+        ScopeType = scope.Type;
+        ScopeId = scope.Id;
+        Role = role;
+        Token = token;
+        InvitedByMemberId = invitedByMemberId;
+        Status = InvitationStatus.Pending;
+        CreatedAtUtc = createdAtUtc;
+    }
+
+    public ScopeRef Scope => new(ScopeType, ScopeId);
+
+    public void Accept(DateTimeOffset whenUtc)
+    {
+        Status = InvitationStatus.Accepted;
+        AcceptedAtUtc = whenUtc;
+    }
+}

src/Modules/TeamUp.Modules.Identity/Domain/Member.cs

@@ -0,0 +1,43 @@
+using TeamUp.SharedKernel.Domain;
+
+namespace TeamUp.Modules.Identity.Domain;
+
+internal enum MemberStatus
+{
+    Invited,
+    Active,
+    Disabled,
+}
+
+/// <summary>An invited/active human in the system. Identity owns the credential; other modules
+/// reference a member only by id (via the public member directory).</summary>
+internal sealed class Member : Entity
+{
+    public string Email { get; private set; } = null!;
+    public string DisplayName { get; private set; } = null!;
+    public string PasswordHash { get; private set; } = null!;
+    public MemberStatus Status { get; private set; }
+    public DateTimeOffset CreatedAtUtc { get; private set; }
+
+    private Member()
+    {
+    }
+
+    public Member(
+        string email,
+        string displayName,
+        string passwordHash,
+        DateTimeOffset createdAtUtc,
+        MemberStatus status = MemberStatus.Active)
+    {
+        Email = email;
+        DisplayName = displayName;
+        PasswordHash = passwordHash;
+        CreatedAtUtc = createdAtUtc;
+        Status = status;
+    }
+
+    public void SetPasswordHash(string passwordHash) => PasswordHash = passwordHash;
+
+    public void Activate() => Status = MemberStatus.Active;
+}

src/Modules/TeamUp.Modules.Identity/Domain/Membership.cs

@@ -0,0 +1,29 @@
+using TeamUp.SharedKernel.Access;
+using TeamUp.SharedKernel.Domain;
+
+namespace TeamUp.Modules.Identity.Domain;
+
+/// <summary>A member's role at a scope. Additive — a member may hold several.</summary>
+internal sealed class Membership : Entity
+{
+    public Guid MemberId { get; private set; }
+    public ScopeType ScopeType { get; private set; }
+    public Guid ScopeId { get; private set; }
+    public RoleType Role { get; private set; }
+    public DateTimeOffset CreatedAtUtc { get; private set; }
+
+    private Membership()
+    {
+    }
+
+    public Membership(Guid memberId, ScopeRef scope, RoleType role, DateTimeOffset createdAtUtc)
+    {
+        MemberId = memberId;
+        ScopeType = scope.Type;
+        ScopeId = scope.Id;
+        Role = role;
+        CreatedAtUtc = createdAtUtc;
+    }
+
+    public ScopeRef Scope => new(ScopeType, ScopeId);
+}

src/Modules/TeamUp.Modules.Identity/Endpoints/IdentityDtos.cs

@@ -0,0 +1,34 @@
+using TeamUp.SharedKernel.Access;
+
+namespace TeamUp.Modules.Identity.Endpoints;
+
+internal sealed record BootstrapRequest(
+    string OrganizationName,
+    string OwnerEmail,
+    string OwnerDisplayName,
+    string OwnerPassword);
+
+internal sealed record BootstrapResponse(string Token, Guid MemberId, Guid OrganizationId);
+
+internal sealed record LoginRequest(string Email, string Password);
+
+internal sealed record AuthResponse(string Token, Guid MemberId);
+
+internal sealed record MembershipDto(string ScopeType, Guid ScopeId, string Role);
+
+internal sealed record MeResponse(
+    Guid MemberId,
+    string Email,
+    string DisplayName,
+    IReadOnlyList<MembershipDto> Memberships);
+
+internal sealed record InviteRequest(
+    string Email,
+    ScopeType ScopeType,
+    Guid ScopeId,
+    RoleType Role,
+    Guid OrganizationId);
+
+internal sealed record InviteResponse(Guid InvitationId, string Token);
+
+internal sealed record AcceptInviteRequest(string Token, string DisplayName, string Password);

src/Modules/TeamUp.Modules.Identity/Endpoints/IdentityEndpoints.cs

@@ -0,0 +1,165 @@
+using System.Security.Cryptography;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Identity;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.EntityFrameworkCore;
+using TeamUp.Modules.Identity.Auth;
+using TeamUp.Modules.Identity.Domain;
+using TeamUp.Modules.Identity.Persistence;
+using TeamUp.SharedKernel.Access;
+using TeamUp.SharedKernel.Modularity;
+
+namespace TeamUp.Modules.Identity.Endpoints;
+
+internal static class IdentityEndpoints
+{
+    public static void Map(IEndpointRouteBuilder endpoints)
+    {
+        var group = endpoints.MapGroup("/api/identity").WithTags("Identity");
+
+        group.MapGet("/ping", () => TypedResults.Ok(new ModulePing("identity")));
+        group.MapPost("/bootstrap", Bootstrap).AllowAnonymous();
+        group.MapPost("/auth/login", Login).AllowAnonymous();
+        group.MapGet("/me", Me).RequireAuthorization();
+        group.MapPost("/invitations", CreateInvitation).RequireAuthorization();
+        group.MapPost("/invitations/accept", AcceptInvitation).AllowAnonymous();
+    }
+
+    private static async Task<IResult> Bootstrap(
+        BootstrapRequest request,
+        IdentityDbContext db,
+        IPasswordHasher<Member> hasher,
+        JwtTokenService tokens,
+        TimeProvider clock,
+        CancellationToken ct)
+    {
+        if (string.IsNullOrWhiteSpace(request.OwnerEmail) || string.IsNullOrWhiteSpace(request.OwnerPassword))
+        {
+            return Results.BadRequest("Owner email and password are required.");
+        }
+
+        if (await db.Members.AnyAsync(ct))
+        {
+            return Results.Conflict("The system is already bootstrapped.");
+        }
+
+        var now = clock.GetUtcNow();
+        var organizationId = Guid.CreateVersion7();
+        var owner = new Member(request.OwnerEmail.Trim(), request.OwnerDisplayName.Trim(), string.Empty, now);
+        owner.SetPasswordHash(hasher.HashPassword(owner, request.OwnerPassword));
+
+        var membership = new Membership(owner.Id, ScopeRef.Org(organizationId), RoleType.Owner, now);
+
+        db.Members.Add(owner);
+        db.Memberships.Add(membership);
+        await db.SaveChangesAsync(ct);
+
+        var token = tokens.Issue(owner, [membership]);
+        return Results.Ok(new BootstrapResponse(token, owner.Id, organizationId));
+    }
+
+    private static async Task<IResult> Login(
+        LoginRequest request,
+        IdentityDbContext db,
+        IPasswordHasher<Member> hasher,
+        JwtTokenService tokens,
+        CancellationToken ct)
+    {
+        var member = await db.Members.FirstOrDefaultAsync(m => m.Email == request.Email, ct);
+        if (member is null || member.Status == MemberStatus.Disabled)
+        {
+            return Results.Unauthorized();
+        }
+
+        var result = hasher.VerifyHashedPassword(member, member.PasswordHash, request.Password);
+        if (result == PasswordVerificationResult.Failed)
+        {
+            return Results.Unauthorized();
+        }
+
+        var memberships = await db.Memberships.Where(m => m.MemberId == member.Id).ToListAsync(ct);
+        return Results.Ok(new AuthResponse(tokens.Issue(member, memberships), member.Id));
+    }
+
+    private static async Task<IResult> Me(ICurrentUser currentUser, IdentityDbContext db, CancellationToken ct)
+    {
+        var member = await db.Members.FirstOrDefaultAsync(m => m.Id == currentUser.MemberId, ct);
+        if (member is null)
+        {
+            return Results.NotFound();
+        }
+
+        var memberships = currentUser.Memberships
+            .Select(m => new MembershipDto(m.Scope.Type.ToString(), m.Scope.Id, m.Role.ToString()))
+            .ToList();
+
+        return Results.Ok(new MeResponse(member.Id, member.Email, member.DisplayName, memberships));
+    }
+
+    private static async Task<IResult> CreateInvitation(
+        InviteRequest request,
+        ICurrentUser currentUser,
+        IPermissionService permissions,
+        IdentityDbContext db,
+        TimeProvider clock,
+        CancellationToken ct)
+    {
+        var targetScope = new ScopeRef(request.ScopeType, request.ScopeId);
+        var orgScope = ScopeRef.Org(request.OrganizationId);
+        var chain = targetScope == orgScope
+            ? new[] { targetScope }
+            : new[] { targetScope, orgScope };
+
+        if (!permissions.Has(Capability.InvitePeople, chain))
+        {
+            return Results.Forbid();
+        }
+
+        if (string.IsNullOrWhiteSpace(request.Email))
+        {
+            return Results.BadRequest("Email is required.");
+        }
+
+        var token = Convert.ToHexString(RandomNumberGenerator.GetBytes(32));
+        var invitation = new Invitation(
+            request.Email.Trim(), targetScope, request.Role, token, currentUser.MemberId, clock.GetUtcNow());
+
+        db.Invitations.Add(invitation);
+        await db.SaveChangesAsync(ct);
+
+        return Results.Ok(new InviteResponse(invitation.Id, token));
+    }
+
+    private static async Task<IResult> AcceptInvitation(
+        AcceptInviteRequest request,
+        IdentityDbContext db,
+        IPasswordHasher<Member> hasher,
+        JwtTokenService tokens,
+        TimeProvider clock,
+        CancellationToken ct)
+    {
+        var invitation = await db.Invitations.FirstOrDefaultAsync(i => i.Token == request.Token, ct);
+        if (invitation is null || invitation.Status != InvitationStatus.Pending)
+        {
+            return Results.BadRequest("Invitation not found or already used.");
+        }
+
+        if (string.IsNullOrWhiteSpace(request.Password) || string.IsNullOrWhiteSpace(request.DisplayName))
+        {
+            return Results.BadRequest("Display name and password are required.");
+        }
+
+        var now = clock.GetUtcNow();
+        var member = new Member(invitation.Email, request.DisplayName.Trim(), string.Empty, now);
+        member.SetPasswordHash(hasher.HashPassword(member, request.Password));
+        var membership = new Membership(member.Id, invitation.Scope, invitation.Role, now);
+        invitation.Accept(now);
+
+        db.Members.Add(member);
+        db.Memberships.Add(membership);
+        await db.SaveChangesAsync(ct);
+
+        return Results.Ok(new AuthResponse(tokens.Issue(member, [membership]), member.Id));
+    }
+}

src/Modules/TeamUp.Modules.Identity/IdentityModule.cs

@@ -1,27 +1,65 @@
-using Microsoft.AspNetCore.Builder;
-using Microsoft.AspNetCore.Http;
+using System.Text;
+using Microsoft.AspNetCore.Authentication.JwtBearer;
+using Microsoft.AspNetCore.Identity;
 using Microsoft.AspNetCore.Routing;
+using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.IdentityModel.Tokens;
+using TeamUp.Modules.Identity.Access;
+using TeamUp.Modules.Identity.Auth;
+using TeamUp.Modules.Identity.Contracts;
+using TeamUp.Modules.Identity.Domain;
+using TeamUp.Modules.Identity.Endpoints;
+using TeamUp.Modules.Identity.Persistence;
+using TeamUp.SharedKernel.Access;
 using TeamUp.SharedKernel.Modularity;
+using TeamUp.SharedKernel.Persistence;
 
 namespace TeamUp.Modules.Identity;
 
-/// <summary>Identity &amp; access: members, memberships, roles, permission enforcement (M1).</summary>
+/// <summary>Identity &amp; access: members, memberships, invitations, JWT auth, permission enforcement (M1).</summary>
 public sealed class IdentityModule : IModule
 {
     public string Name => "identity";
 
     public void Register(IServiceCollection services, IConfiguration configuration)
     {
-        // Skeleton: no services yet. M1 introduces this module's (internal) DbContext,
-        // FluentValidation validators, and domain services here.
+        var connectionString = configuration.GetConnectionString("Postgres")
+            ?? throw new InvalidOperationException("Missing connection string 'ConnectionStrings:Postgres'.");
+
+        services.AddDbContext<IdentityDbContext>(options => options.UseNpgsql(connectionString));
+        services.AddScoped<IModuleDbContext>(sp => sp.GetRequiredService<IdentityDbContext>());
+
+        services.TryAddSingleton(TimeProvider.System);
+        services.AddHttpContextAccessor();
+        services.AddScoped<ICurrentUser, CurrentUser>();
+        services.AddScoped<IPermissionService, PermissionService>();
+        services.AddScoped<IMemberDirectory, MemberDirectory>();
+        services.AddScoped<JwtTokenService>();
+        services.AddSingleton<IPasswordHasher<Member>, PasswordHasher<Member>>();
+
+        services.Configure<JwtOptions>(configuration.GetSection(JwtOptions.SectionName));
+        var jwt = configuration.GetSection(JwtOptions.SectionName).Get<JwtOptions>() ?? new JwtOptions();
+
+        services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
+            .AddJwtBearer(options =>
+            {
+                options.MapInboundClaims = false;
+                options.TokenValidationParameters = new TokenValidationParameters
+                {
+                    ValidateIssuer = true,
+                    ValidIssuer = jwt.Issuer,
+                    ValidateAudience = true,
+                    ValidAudience = jwt.Audience,
+                    ValidateIssuerSigningKey = true,
+                    IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(jwt.Secret)),
+                    ValidateLifetime = true,
+                };
+            });
+        services.AddAuthorization();
     }
 
-    public void MapEndpoints(IEndpointRouteBuilder endpoints)
-    {
-        endpoints.MapGroup($"/api/{Name}")
-            .WithTags("Identity")
-            .MapGet("/ping", () => TypedResults.Ok(new ModulePing(Name)));
-    }
+    public void MapEndpoints(IEndpointRouteBuilder endpoints) => IdentityEndpoints.Map(endpoints);
 }

src/Modules/TeamUp.Modules.Identity/Persistence/IdentityDbContext.cs

@@ -0,0 +1,54 @@
+using Microsoft.EntityFrameworkCore;
+using TeamUp.Modules.Identity.Domain;
+using TeamUp.SharedKernel.Persistence;
+
+namespace TeamUp.Modules.Identity.Persistence;
+
+internal sealed class IdentityDbContext(DbContextOptions<IdentityDbContext> options)
+    : DbContext(options), IModuleDbContext
+{
+    public DbSet<Member> Members => Set<Member>();
+    public DbSet<Membership> Memberships => Set<Membership>();
+    public DbSet<Invitation> Invitations => Set<Invitation>();
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        modelBuilder.HasDefaultSchema("identity");
+
+        modelBuilder.Entity<Member>(member =>
+        {
+            member.ToTable("members");
+            member.HasKey(m => m.Id);
+            member.Property(m => m.Email).HasMaxLength(256).IsRequired();
+            member.HasIndex(m => m.Email).IsUnique();
+            member.Property(m => m.DisplayName).HasMaxLength(128).IsRequired();
+            member.Property(m => m.PasswordHash).HasMaxLength(512).IsRequired();
+            member.Property(m => m.Status).HasConversion<string>().HasMaxLength(32);
+        });
+
+        modelBuilder.Entity<Membership>(membership =>
+        {
+            membership.ToTable("memberships");
+            membership.HasKey(m => m.Id);
+            membership.Property(m => m.ScopeType).HasConversion<string>().HasMaxLength(32);
+            membership.Property(m => m.Role).HasConversion<string>().HasMaxLength(32);
+            membership.Ignore(m => m.Scope);
+            membership.HasIndex(m => m.MemberId);
+            membership.HasIndex(m => new { m.MemberId, m.ScopeType, m.ScopeId, m.Role }).IsUnique();
+        });
+
+        modelBuilder.Entity<Invitation>(invitation =>
+        {
+            invitation.ToTable("invitations");
+            invitation.HasKey(i => i.Id);
+            invitation.Property(i => i.Email).HasMaxLength(256).IsRequired();
+            invitation.Property(i => i.Token).HasMaxLength(128).IsRequired();
+            invitation.HasIndex(i => i.Token).IsUnique();
+            invitation.HasIndex(i => i.Email);
+            invitation.Property(i => i.ScopeType).HasConversion<string>().HasMaxLength(32);
+            invitation.Property(i => i.Role).HasConversion<string>().HasMaxLength(32);
+            invitation.Property(i => i.Status).HasConversion<string>().HasMaxLength(32);
+            invitation.Ignore(i => i.Scope);
+        });
+    }
+}

src/Modules/TeamUp.Modules.Identity/Persistence/IdentityDbContextFactory.cs

@@ -0,0 +1,21 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Design;
+
+namespace TeamUp.Modules.Identity.Persistence;
+
+/// <summary>Design-time factory so `dotnet ef` can build the internal context without a host.</summary>
+internal sealed class IdentityDbContextFactory : IDesignTimeDbContextFactory<IdentityDbContext>
+{
+    public IdentityDbContext CreateDbContext(string[] args)
+    {
+        var connectionString =
+            Environment.GetEnvironmentVariable("ConnectionStrings__Postgres")
+            ?? "Host=localhost;Port=5432;Database=teamup;Username=teamup;Password=teamup";
+
+        var options = new DbContextOptionsBuilder<IdentityDbContext>()
+            .UseNpgsql(connectionString)
+            .Options;
+
+        return new IdentityDbContext(options);
+    }
+}

src/Modules/TeamUp.Modules.Identity/Persistence/MemberDirectory.cs

@@ -0,0 +1,24 @@
+using Microsoft.EntityFrameworkCore;
+using TeamUp.Modules.Identity.Contracts;
+
+namespace TeamUp.Modules.Identity.Persistence;
+
+internal sealed class MemberDirectory(IdentityDbContext db) : IMemberDirectory
+{
+    public async Task<MemberSummary?> FindByIdAsync(Guid memberId, CancellationToken cancellationToken = default) =>
+        await db.Members
+            .Where(m => m.Id == memberId)
+            .Select(m => new MemberSummary(m.Id, m.Email, m.DisplayName))
+            .FirstOrDefaultAsync(cancellationToken);
+
+    public async Task<IReadOnlyDictionary<Guid, MemberSummary>> GetByIdsAsync(
+        IReadOnlyCollection<Guid> memberIds,
+        CancellationToken cancellationToken = default)
+    {
+        var ids = memberIds.ToHashSet();
+        return await db.Members
+            .Where(m => ids.Contains(m.Id))
+            .Select(m => new MemberSummary(m.Id, m.Email, m.DisplayName))
+            .ToDictionaryAsync(m => m.Id, cancellationToken);
+    }
+}

src/Modules/TeamUp.Modules.Identity/Persistence/Migrations/20260609042521_InitialIdentity.Designer.cs

@@ -0,0 +1,156 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+using TeamUp.Modules.Identity.Persistence;
+
+#nullable disable
+
+namespace TeamUp.Modules.Identity.Persistence.Migrations
+{
+    [DbContext(typeof(IdentityDbContext))]
+    [Migration("20260609042521_InitialIdentity")]
+    partial class InitialIdentity
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasDefaultSchema("identity")
+                .HasAnnotation("ProductVersion", "10.0.8")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
+
+            modelBuilder.Entity("TeamUp.Modules.Identity.Domain.Invitation", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset?>("AcceptedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.Property<Guid>("InvitedByMemberId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Role")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
+                    b.Property<Guid>("ScopeId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("ScopeType")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
+                    b.Property<string>("Status")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
+                    b.Property<string>("Token")
+                        .IsRequired()
+                        .HasMaxLength(128)
+                        .HasColumnType("character varying(128)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Email");
+
+                    b.HasIndex("Token")
+                        .IsUnique();
+
+                    b.ToTable("invitations", "identity");
+                });
+
+            modelBuilder.Entity("TeamUp.Modules.Identity.Domain.Member", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("DisplayName")
+                        .IsRequired()
+                        .HasMaxLength(128)
+                        .HasColumnType("character varying(128)");
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.Property<string>("PasswordHash")
+                        .IsRequired()
+                        .HasMaxLength(512)
+                        .HasColumnType("character varying(512)");
+
+                    b.Property<string>("Status")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Email")
+                        .IsUnique();
+
+                    b.ToTable("members", "identity");
+                });
+
+            modelBuilder.Entity("TeamUp.Modules.Identity.Domain.Membership", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("MemberId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Role")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
+                    b.Property<Guid>("ScopeId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("ScopeType")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("MemberId");
+
+                    b.HasIndex("MemberId", "ScopeType", "ScopeId", "Role")
+                        .IsUnique();
+
+                    b.ToTable("memberships", "identity");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

src/Modules/TeamUp.Modules.Identity/Persistence/Migrations/20260609042521_InitialIdentity.cs

@@ -0,0 +1,122 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace TeamUp.Modules.Identity.Persistence.Migrations
+{
+    /// <inheritdoc />
+    public partial class InitialIdentity : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.EnsureSchema(
+                name: "identity");
+
+            migrationBuilder.CreateTable(
+                name: "invitations",
+                schema: "identity",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uuid", nullable: false),
+                    Email = table.Column<string>(type: "character varying(256)", maxLength: 256, nullable: false),
+                    ScopeType = table.Column<string>(type: "character varying(32)", maxLength: 32, nullable: false),
+                    ScopeId = table.Column<Guid>(type: "uuid", nullable: false),
+                    Role = table.Column<string>(type: "character varying(32)", maxLength: 32, nullable: false),
+                    Token = table.Column<string>(type: "character varying(128)", maxLength: 128, nullable: false),
+                    Status = table.Column<string>(type: "character varying(32)", maxLength: 32, nullable: false),
+                    InvitedByMemberId = table.Column<Guid>(type: "uuid", nullable: false),
+                    CreatedAtUtc = table.Column<DateTimeOffset>(type: "timestamp with time zone", nullable: false),
+                    AcceptedAtUtc = table.Column<DateTimeOffset>(type: "timestamp with time zone", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_invitations", x => x.Id);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "members",
+                schema: "identity",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uuid", nullable: false),
+                    Email = table.Column<string>(type: "character varying(256)", maxLength: 256, nullable: false),
+                    DisplayName = table.Column<string>(type: "character varying(128)", maxLength: 128, nullable: false),
+                    PasswordHash = table.Column<string>(type: "character varying(512)", maxLength: 512, nullable: false),
+                    Status = table.Column<string>(type: "character varying(32)", maxLength: 32, nullable: false),
+                    CreatedAtUtc = table.Column<DateTimeOffset>(type: "timestamp with time zone", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_members", x => x.Id);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "memberships",
+                schema: "identity",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uuid", nullable: false),
+                    MemberId = table.Column<Guid>(type: "uuid", nullable: false),
+                    ScopeType = table.Column<string>(type: "character varying(32)", maxLength: 32, nullable: false),
+                    ScopeId = table.Column<Guid>(type: "uuid", nullable: false),
+                    Role = table.Column<string>(type: "character varying(32)", maxLength: 32, nullable: false),
+                    CreatedAtUtc = table.Column<DateTimeOffset>(type: "timestamp with time zone", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_memberships", x => x.Id);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_invitations_Email",
+                schema: "identity",
+                table: "invitations",
+                column: "Email");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_invitations_Token",
+                schema: "identity",
+                table: "invitations",
+                column: "Token",
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_members_Email",
+                schema: "identity",
+                table: "members",
+                column: "Email",
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_memberships_MemberId",
+                schema: "identity",
+                table: "memberships",
+                column: "MemberId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_memberships_MemberId_ScopeType_ScopeId_Role",
+                schema: "identity",
+                table: "memberships",
+                columns: new[] { "MemberId", "ScopeType", "ScopeId", "Role" },
+                unique: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "invitations",
+                schema: "identity");
+
+            migrationBuilder.DropTable(
+                name: "members",
+                schema: "identity");
+
+            migrationBuilder.DropTable(
+                name: "memberships",
+                schema: "identity");
+        }
+    }
+}

src/Modules/TeamUp.Modules.Identity/Persistence/Migrations/IdentityDbContextModelSnapshot.cs

@@ -0,0 +1,153 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+using TeamUp.Modules.Identity.Persistence;
+
+#nullable disable
+
+namespace TeamUp.Modules.Identity.Persistence.Migrations
+{
+    [DbContext(typeof(IdentityDbContext))]
+    partial class IdentityDbContextModelSnapshot : ModelSnapshot
+    {
+        protected override void BuildModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasDefaultSchema("identity")
+                .HasAnnotation("ProductVersion", "10.0.8")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
+
+            modelBuilder.Entity("TeamUp.Modules.Identity.Domain.Invitation", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset?>("AcceptedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.Property<Guid>("InvitedByMemberId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Role")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
+                    b.Property<Guid>("ScopeId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("ScopeType")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
+                    b.Property<string>("Status")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
+                    b.Property<string>("Token")
+                        .IsRequired()
+                        .HasMaxLength(128)
+                        .HasColumnType("character varying(128)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Email");
+
+                    b.HasIndex("Token")
+                        .IsUnique();
+
+                    b.ToTable("invitations", "identity");
+                });
+
+            modelBuilder.Entity("TeamUp.Modules.Identity.Domain.Member", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("DisplayName")
+                        .IsRequired()
+                        .HasMaxLength(128)
+                        .HasColumnType("character varying(128)");
+
+                    b.Property<string>("Email")
+                        .IsRequired()
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.Property<string>("PasswordHash")
+                        .IsRequired()
+                        .HasMaxLength(512)
+                        .HasColumnType("character varying(512)");
+
+                    b.Property<string>("Status")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Email")
+                        .IsUnique();
+
+                    b.ToTable("members", "identity");
+                });
+
+            modelBuilder.Entity("TeamUp.Modules.Identity.Domain.Membership", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<Guid>("MemberId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Role")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
+                    b.Property<Guid>("ScopeId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("ScopeType")
+                        .IsRequired()
+                        .HasMaxLength(32)
+                        .HasColumnType("character varying(32)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("MemberId");
+
+                    b.HasIndex("MemberId", "ScopeType", "ScopeId", "Role")
+                        .IsUnique();
+
+                    b.ToTable("memberships", "identity");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

src/Modules/TeamUp.Modules.Identity/TeamUp.Modules.Identity.csproj

@@ -1,10 +1,20 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
-  <!-- A self-contained module. References SharedKernel ONLY (ASP.NET flows transitively for the
-       IModule seam). M1 adds this module's EF/Npgsql/FluentValidation/Mapperly packages when it
-       gains an (internal) DbContext and validators. It must never reference another module. -->
+  <!-- Identity & access: members, memberships, invitations, JWT auth, permission enforcement.
+       References SharedKernel only; never another module. -->
   <ItemGroup>
     <ProjectReference Include="..\..\Shared\TeamUp.SharedKernel\TeamUp.SharedKernel.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Microsoft.EntityFrameworkCore" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" PrivateAssets="all" />
+    <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" />
+    <PackageReference Include="FluentValidation" />
+    <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" />
+    <PackageReference Include="Microsoft.Extensions.Identity.Core" />
+    <PackageReference Include="Microsoft.IdentityModel.JsonWebTokens" />
+    <PackageReference Include="Microsoft.IdentityModel.Tokens" />
+  </ItemGroup>
+
 </Project>

src/Shared/TeamUp.SharedKernel/Access/AccessPolicy.cs

@@ -0,0 +1,26 @@
+namespace TeamUp.SharedKernel.Access;
+
+/// <summary>
+/// The role × capability matrix (docs/PRODUCT.md "Access / RBAC"). Pure policy — no scope logic
+/// here; scope coverage is applied by <see cref="IPermissionService"/>. Owner is org-wide and can
+/// do everything; TeamOwner is scoped to its own team; Member works tasks; Viewer reads only.
+/// </summary>
+public static class AccessPolicy
+{
+    public static bool Permits(RoleType role, Capability capability) => role switch
+    {
+        RoleType.Owner => true,
+        RoleType.TeamOwner => capability is
+            Capability.InvitePeople
+            or Capability.CreateProductsAndTeams
+            or Capability.ConfigureAgents
+            or Capability.SetAutonomy
+            or Capability.ApproveHeldActions
+            or Capability.WorkTasks
+            or Capability.ViewBoard
+            or Capability.ViewAuditLog,
+        RoleType.Member => capability is Capability.WorkTasks or Capability.ViewBoard,
+        RoleType.Viewer => capability is Capability.ViewBoard,
+        _ => false,
+    };
+}

src/Shared/TeamUp.SharedKernel/Access/Capability.cs

@@ -0,0 +1,19 @@
+namespace TeamUp.SharedKernel.Access;
+
+/// <summary>
+/// A permission-checked action, evaluated against a scope. Mirrors the capability rows of the
+/// access matrix in docs/PRODUCT.md ("Access / RBAC").
+/// </summary>
+public enum Capability
+{
+    ManageBilling,
+    ManageApiKeys,
+    InvitePeople,
+    CreateProductsAndTeams,
+    ConfigureAgents,
+    SetAutonomy,
+    ApproveHeldActions,
+    WorkTasks,
+    ViewBoard,
+    ViewAuditLog,
+}

src/Shared/TeamUp.SharedKernel/Access/ICurrentUser.cs

@@ -0,0 +1,20 @@
+namespace TeamUp.SharedKernel.Access;
+
+/// <summary>A role held at a scope.</summary>
+public readonly record struct ScopedRole(ScopeRef Scope, RoleType Role);
+
+/// <summary>
+/// The authenticated principal for the current request — or unauthenticated. Resolved from the
+/// JWT by the Identity module; available to every module via DI.
+/// </summary>
+public interface ICurrentUser
+{
+    bool IsAuthenticated { get; }
+
+    /// <summary>The member id. Throws if not authenticated — guard with <see cref="IsAuthenticated"/>.</summary>
+    Guid MemberId { get; }
+
+    string Email { get; }
+
+    IReadOnlyList<ScopedRole> Memberships { get; }
+}

src/Shared/TeamUp.SharedKernel/Access/IPermissionService.cs

@@ -0,0 +1,12 @@
+namespace TeamUp.SharedKernel.Access;
+
+/// <summary>
+/// Evaluates whether the current user may perform a capability at a scope. The caller passes the
+/// scope chain from most-specific to broadest (e.g. a team, then its org); a covering role at any
+/// link grants the capability. This keeps Identity free of OrgBoard's scope hierarchy — the module
+/// performing the action supplies the chain it already knows.
+/// </summary>
+public interface IPermissionService
+{
+    bool Has(Capability capability, params ScopeRef[] scopeChain);
+}

src/Shared/TeamUp.SharedKernel/Access/RoleType.cs

@@ -0,0 +1,10 @@
+namespace TeamUp.SharedKernel.Access;
+
+/// <summary>A role granted to a member at a scope. Memberships are additive.</summary>
+public enum RoleType
+{
+    Owner,
+    TeamOwner,
+    Member,
+    Viewer,
+}

src/Shared/TeamUp.SharedKernel/Access/Scope.cs

@@ -0,0 +1,18 @@
+namespace TeamUp.SharedKernel.Access;
+
+/// <summary>The kind of scope a role is granted at. V1 uses Organization and Team.</summary>
+public enum ScopeType
+{
+    Organization,
+    Division,
+    Product,
+    Team,
+}
+
+/// <summary>A reference to the scope a role applies to (additive across memberships).</summary>
+public readonly record struct ScopeRef(ScopeType Type, Guid Id)
+{
+    public static ScopeRef Org(Guid id) => new(ScopeType.Organization, id);
+
+    public static ScopeRef Team(Guid id) => new(ScopeType.Team, id);
+}