diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.Security/Jwt/JwtTokenService.cs b/src/Server/ZB.MOM.WW.OtOpcUa.Security/Jwt/JwtTokenService.cs
index a240f4b9..89981d9e 100644
--- a/src/Server/ZB.MOM.WW.OtOpcUa.Security/Jwt/JwtTokenService.cs
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.Security/Jwt/JwtTokenService.cs
@@ -23,9 +23,27 @@ public sealed class JwtTokenService
     public const string UsernameClaimType = ZbClaimTypes.Username;
 
     /// <summary>
-    /// Role claim type used in the JWT payload. Kept as the short "Role" key for the
-    /// bearer token payload; the cookie-principal uses <see cref="ZbClaimTypes.Role"/>
-    /// (= <see cref="ClaimTypes.Role"/>) for framework role resolution.
+    /// Role claim type used in the JWT payload.
+    /// <para>
+    /// <b>Issued-only / no internal JwtBearer scheme:</b> OtOpcUa uses a single Cookie
+    /// authentication scheme; the JWT is minted by the <c>/auth/token</c> endpoint and
+    /// consumed externally (e.g. by OPC-UA clients or automation scripts). There is no
+    /// <c>AddJwtBearer</c> pipeline in OtOpcUa — the cookie stores the
+    /// <see cref="System.Security.Claims.ClaimsPrincipal"/> directly. Because no internal
+    /// bearer validation path exists, the short "Role" key is intentionally used here rather
+    /// than the long <see cref="ClaimTypes.Role"/> URI; external consumers receive exactly the
+    /// key they expect.
+    /// </para>
+    /// <para>
+    /// <b>If a JwtBearer scheme is ever added:</b> the
+    /// <see cref="Microsoft.IdentityModel.Tokens.TokenValidationParameters"/> passed to
+    /// <c>AddJwtBearer</c> MUST set <c>RoleClaimType = JwtTokenService.RoleClaimType</c> (and
+    /// <c>NameClaimType = JwtTokenService.UsernameClaimType</c>) so that
+    /// <c>[Authorize(Roles=...)]</c> and <c>ClaimsPrincipal.IsInRole</c> resolve correctly.
+    /// <see cref="BuildValidationParameters"/> is already wired to do this and MUST be used
+    /// rather than constructing <see cref="Microsoft.IdentityModel.Tokens.TokenValidationParameters"/>
+    /// ad hoc.
+    /// </para>
     /// </summary>
     public const string RoleClaimType = "Role";
 
@@ -66,6 +84,8 @@ public sealed class JwtTokenService
             new(DisplayNameClaimType, displayName),
             new(UsernameClaimType, username),
         };
+        // Role claims use the short RoleClaimType key ("Role") — see the <see cref="RoleClaimType"/>
+        // doc comment for the issued-only rationale and the JwtBearer caveat.
         foreach (var role in roles)
             claims.Add(new Claim(RoleClaimType, role));
 
@@ -86,18 +106,9 @@ public sealed class JwtTokenService
     public bool TryValidate(string token, out ClaimsPrincipal? principal)
     {
         principal = null;
-        var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_options.SigningKey));
-        var parameters = new TokenValidationParameters
-        {
-            ValidateIssuer = true,
-            ValidIssuer = _options.Issuer,
-            ValidateAudience = true,
-            ValidAudience = _options.Audience,
-            ValidateLifetime = true,
-            ValidateIssuerSigningKey = true,
-            IssuerSigningKey = key,
-            ClockSkew = TimeSpan.Zero,
-        };
+        // Delegate to BuildValidationParameters so RoleClaimType/NameClaimType are always in
+        // sync with the mint constants — no risk of this method diverging from the bearer path.
+        var parameters = BuildValidationParameters();
 
         try
         {
@@ -115,6 +126,14 @@ public sealed class JwtTokenService
     /// <summary>
     /// Returns the validation parameters that the JwtBearer middleware should use. Centralised
     /// so the bearer pipeline can't drift from <see cref="TryValidate"/>.
+    /// <para>
+    /// <b>Note:</b> <see cref="TokenValidationParameters.RoleClaimType"/> is set to
+    /// <see cref="RoleClaimType"/> and <see cref="TokenValidationParameters.NameClaimType"/> is
+    /// set to <see cref="UsernameClaimType"/> so that <c>[Authorize(Roles=...)]</c> and
+    /// <c>ClaimsPrincipal.IsInRole</c> resolve against the short role key ("Role") that
+    /// <see cref="Issue"/> mints — not the JWT-default "role" or "name" keys. This is the
+    /// required pairing whenever a JwtBearer scheme is wired.
+    /// </para>
     /// </summary>
     public TokenValidationParameters BuildValidationParameters() => new()
     {
@@ -126,5 +145,9 @@ public sealed class JwtTokenService
         ValidateIssuerSigningKey = true,
         IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_options.SigningKey)),
         ClockSkew = TimeSpan.Zero,
+        // Pair these with the constants used at mint time so role/name resolution is correct
+        // if this is ever passed to AddJwtBearer. See RoleClaimType doc comment for rationale.
+        RoleClaimType = RoleClaimType,
+        NameClaimType = UsernameClaimType,
     };
 }
diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.Security.Tests/AuthEndpointsIntegrationTests.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.Security.Tests/AuthEndpointsIntegrationTests.cs
index bbd92169..4bcb3452 100644
--- a/tests/Server/ZB.MOM.WW.OtOpcUa.Security.Tests/AuthEndpointsIntegrationTests.cs
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.Security.Tests/AuthEndpointsIntegrationTests.cs
@@ -19,6 +19,7 @@ using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
 using ZB.MOM.WW.OtOpcUa.Configuration.Enums;
 using ZB.MOM.WW.OtOpcUa.Configuration.Services;
 using ZB.MOM.WW.OtOpcUa.Security.Endpoints;
+using ZB.MOM.WW.OtOpcUa.Security.Jwt;
 using ZB.MOM.WW.OtOpcUa.Security.Ldap;
 
 namespace ZB.MOM.WW.OtOpcUa.Security.Tests;
@@ -360,11 +361,18 @@ public sealed class AuthEndpointsIntegrationTests : IAsyncLifetime
     /// <summary>
     /// Task 1.5 — JWT payload uses canonical claim keys: after login and token issue the JWT
     /// payload segment MUST contain "zb:username" and "zb:displayname" keys (not the old short
-    /// "Username"/"DisplayName" strings).
+    /// "Username"/"DisplayName" strings), AND the role claim(s) MUST be carried under the key
+    /// <see cref="JwtTokenService.RoleClaimType"/> (currently the short "Role" key — intentionally
+    /// NOT the long ClaimTypes.Role URI, because OtOpcUa is JWT-issued-only; see
+    /// <see cref="JwtTokenService.RoleClaimType"/> docs for the rationale and the caveat that
+    /// applies if a JwtBearer scheme is ever added).
     /// </summary>
     [Fact]
     public async Task Token_payload_uses_canonical_zb_claim_keys()
     {
+        // Arrange — the appsettings baseline maps group "ReadOnly" → role "ConfigViewer", so alice
+        // (whose groups are ["ReadOnly"]) will carry at least one role in the issued JWT.
+        // No extra DB rows needed — the appsettings GroupToRole entry is always active.
         var client = NewClient();
 
         var loginResp = await client.PostAsJsonAsync("/auth/login",
@@ -391,6 +399,19 @@ public sealed class AuthEndpointsIntegrationTests : IAsyncLifetime
             "JWT payload must carry 'zb:displayname' claim (canonical ZbClaimTypes.DisplayName)");
         displayNameEl.GetString().ShouldBe("Alice User");
 
+        // Role claim(s) must be carried under JwtTokenService.RoleClaimType (= "Role").
+        // This pins the role-key contract: any future rename of RoleClaimType will be caught here.
+        // The appsettings "ReadOnly" → "ConfigViewer" mapping guarantees alice has ≥1 role.
+        payloadJson.TryGetProperty(JwtTokenService.RoleClaimType, out var roleEl).ShouldBeTrue(
+            $"JWT payload must carry at least one role under JwtTokenService.RoleClaimType " +
+            $"(\"{JwtTokenService.RoleClaimType}\")");
+        // The role value may be a string (single) or array (multiple); either way it must be non-empty.
+        if (roleEl.ValueKind == JsonValueKind.Array)
+            roleEl.EnumerateArray().Select(e => e.GetString()).ShouldNotBeEmpty(
+                "JWT role array must contain at least one role value");
+        else
+            roleEl.GetString().ShouldNotBeNullOrEmpty("JWT role value must not be empty");
+
         // Old short-name literals must NOT be present.
         payloadJson.TryGetProperty("Username", out _).ShouldBeFalse(
             "JWT payload must not carry old 'Username' key after Task 1.5 migration");