diff --git a/docs/migration/contract-extraction-map.md b/docs/migration/contract-extraction-map.md
index a1a120e..e0860fa 100644
--- a/docs/migration/contract-extraction-map.md
+++ b/docs/migration/contract-extraction-map.md
@@ -8,6 +8,7 @@
 | thalos-service policy contracts | Contracts/Policies | Preserve policy semantics and required fields |
 | thalos-service policy context contracts | Contracts/Context | Keep field naming stable for compatibility window |
 | thalos-bff refresh session contracts | Contracts/Sessions | Candidate for shared capability standardization |
+| provider flow metadata (JWT/Azure/Google) | Contracts/Conventions | Provider metadata stays transport-neutral and additive |
 
 ## Namespace Strategy
 - Current Thalos namespaces are mapped to `BuildingBlock.Identity.Contracts.*`.
@@ -18,3 +19,4 @@
 2. Add compatibility bridge in Thalos consumers.
 3. Migrate service consumers first, then BFF consumers.
 4. Deprecate old namespace usage after compatibility window.
+5. Keep provider enum and provider-specific fields additive to avoid breaking consumers.
diff --git a/src/BuildingBlock.Identity.Contracts/Conventions/IdentityAuthProvider.cs b/src/BuildingBlock.Identity.Contracts/Conventions/IdentityAuthProvider.cs
new file mode 100644
index 0000000..6d4001b
--- /dev/null
+++ b/src/BuildingBlock.Identity.Contracts/Conventions/IdentityAuthProvider.cs
@@ -0,0 +1,22 @@
+namespace BuildingBlock.Identity.Contracts.Conventions;
+
+/// <summary>
+/// Supported identity authentication providers.
+/// </summary>
+public enum IdentityAuthProvider
+{
+    /// <summary>
+    /// AgileWebs-issued internal JWT flow.
+    /// </summary>
+    InternalJwt = 0,
+
+    /// <summary>
+    /// Microsoft Entra ID / Azure AD OAuth/OIDC flow.
+    /// </summary>
+    AzureAd = 1,
+
+    /// <summary>
+    /// Google OAuth/OIDC flow.
+    /// </summary>
+    Google = 2
+}
diff --git a/src/BuildingBlock.Identity.Contracts/Grpc/IdentityPolicyGrpcContract.cs b/src/BuildingBlock.Identity.Contracts/Grpc/IdentityPolicyGrpcContract.cs
index d4416e2..d508935 100644
--- a/src/BuildingBlock.Identity.Contracts/Grpc/IdentityPolicyGrpcContract.cs
+++ b/src/BuildingBlock.Identity.Contracts/Grpc/IdentityPolicyGrpcContract.cs
@@ -6,4 +6,9 @@ namespace BuildingBlock.Identity.Contracts.Grpc;
 /// <param name="SubjectId">Identity subject identifier.</param>
 /// <param name="TenantId">Tenant identifier.</param>
 /// <param name="PermissionCode">Permission code.</param>
-public sealed record IdentityPolicyGrpcContract(string SubjectId, string TenantId, string PermissionCode);
+/// <param name="Provider">Auth provider.</param>
+public sealed record IdentityPolicyGrpcContract(
+    string SubjectId,
+    string TenantId,
+    string PermissionCode,
+    string Provider = "InternalJwt");
diff --git a/src/BuildingBlock.Identity.Contracts/Requests/EvaluateIdentityPolicyRequest.cs b/src/BuildingBlock.Identity.Contracts/Requests/EvaluateIdentityPolicyRequest.cs
index 078c350..f60ad23 100644
--- a/src/BuildingBlock.Identity.Contracts/Requests/EvaluateIdentityPolicyRequest.cs
+++ b/src/BuildingBlock.Identity.Contracts/Requests/EvaluateIdentityPolicyRequest.cs
@@ -1,4 +1,5 @@
 using BuildingBlock.Identity.Contracts.Abstractions;
+using BuildingBlock.Identity.Contracts.Conventions;
 
 namespace BuildingBlock.Identity.Contracts.Requests;
 
@@ -8,5 +9,10 @@ namespace BuildingBlock.Identity.Contracts.Requests;
 /// <param name="SubjectId">Identity subject identifier.</param>
 /// <param name="TenantId">Tenant identifier.</param>
 /// <param name="PermissionCode">Permission code to evaluate.</param>
-public sealed record EvaluateIdentityPolicyRequest(string SubjectId, string TenantId, string PermissionCode)
+/// <param name="Provider">Auth provider used for the request.</param>
+public sealed record EvaluateIdentityPolicyRequest(
+    string SubjectId,
+    string TenantId,
+    string PermissionCode,
+    IdentityAuthProvider Provider = IdentityAuthProvider.InternalJwt)
     : IIdentityCapabilityContract;
diff --git a/src/BuildingBlock.Identity.Contracts/Requests/ExchangeIdentityProviderTokenRequest.cs b/src/BuildingBlock.Identity.Contracts/Requests/ExchangeIdentityProviderTokenRequest.cs
new file mode 100644
index 0000000..8b992f5
--- /dev/null
+++ b/src/BuildingBlock.Identity.Contracts/Requests/ExchangeIdentityProviderTokenRequest.cs
@@ -0,0 +1,17 @@
+using BuildingBlock.Identity.Contracts.Abstractions;
+using BuildingBlock.Identity.Contracts.Conventions;
+
+namespace BuildingBlock.Identity.Contracts.Requests;
+
+/// <summary>
+/// Requests identity provider token exchange for a subject token.
+/// </summary>
+/// <param name="TenantId">Tenant identifier.</param>
+/// <param name="Provider">External identity provider.</param>
+/// <param name="ExternalToken">Provider-issued token (id/access token).</param>
+/// <param name="CorrelationId">Correlation identifier.</param>
+public sealed record ExchangeIdentityProviderTokenRequest(
+    string TenantId,
+    IdentityAuthProvider Provider,
+    string ExternalToken,
+    string CorrelationId = "") : IIdentityCapabilityContract;
diff --git a/src/BuildingBlock.Identity.Contracts/Requests/IdentityPolicyContextRequest.cs b/src/BuildingBlock.Identity.Contracts/Requests/IdentityPolicyContextRequest.cs
index 60a2515..7ab75d5 100644
--- a/src/BuildingBlock.Identity.Contracts/Requests/IdentityPolicyContextRequest.cs
+++ b/src/BuildingBlock.Identity.Contracts/Requests/IdentityPolicyContextRequest.cs
@@ -1,4 +1,5 @@
 using BuildingBlock.Identity.Contracts.Abstractions;
+using BuildingBlock.Identity.Contracts.Conventions;
 
 namespace BuildingBlock.Identity.Contracts.Requests;
 
@@ -8,5 +9,10 @@ namespace BuildingBlock.Identity.Contracts.Requests;
 /// <param name="SubjectId">Identity subject identifier.</param>
 /// <param name="TenantId">Tenant identifier.</param>
 /// <param name="PermissionCode">Permission code to evaluate.</param>
-public sealed record IdentityPolicyContextRequest(string SubjectId, string TenantId, string PermissionCode)
+/// <param name="Provider">Auth provider used for the request.</param>
+public sealed record IdentityPolicyContextRequest(
+    string SubjectId,
+    string TenantId,
+    string PermissionCode,
+    IdentityAuthProvider Provider = IdentityAuthProvider.InternalJwt)
     : IIdentityCapabilityContract;
diff --git a/src/BuildingBlock.Identity.Contracts/Requests/IssueIdentityTokenRequest.cs b/src/BuildingBlock.Identity.Contracts/Requests/IssueIdentityTokenRequest.cs
index 23d5b4e..7154b43 100644
--- a/src/BuildingBlock.Identity.Contracts/Requests/IssueIdentityTokenRequest.cs
+++ b/src/BuildingBlock.Identity.Contracts/Requests/IssueIdentityTokenRequest.cs
@@ -1,4 +1,5 @@
 using BuildingBlock.Identity.Contracts.Abstractions;
+using BuildingBlock.Identity.Contracts.Conventions;
 
 namespace BuildingBlock.Identity.Contracts.Requests;
 
@@ -7,4 +8,10 @@ namespace BuildingBlock.Identity.Contracts.Requests;
 /// </summary>
 /// <param name="SubjectId">Identity subject identifier.</param>
 /// <param name="TenantId">Tenant identifier.</param>
-public sealed record IssueIdentityTokenRequest(string SubjectId, string TenantId) : IIdentityCapabilityContract;
+/// <param name="Provider">Auth provider used for the request.</param>
+/// <param name="ExternalToken">External provider token when applicable.</param>
+public sealed record IssueIdentityTokenRequest(
+    string SubjectId,
+    string TenantId,
+    IdentityAuthProvider Provider = IdentityAuthProvider.InternalJwt,
+    string ExternalToken = "") : IIdentityCapabilityContract;
diff --git a/src/BuildingBlock.Identity.Contracts/Requests/RefreshIdentitySessionRequest.cs b/src/BuildingBlock.Identity.Contracts/Requests/RefreshIdentitySessionRequest.cs
index d0a1617..9050aae 100644
--- a/src/BuildingBlock.Identity.Contracts/Requests/RefreshIdentitySessionRequest.cs
+++ b/src/BuildingBlock.Identity.Contracts/Requests/RefreshIdentitySessionRequest.cs
@@ -1,4 +1,5 @@
 using BuildingBlock.Identity.Contracts.Abstractions;
+using BuildingBlock.Identity.Contracts.Conventions;
 
 namespace BuildingBlock.Identity.Contracts.Requests;
 
@@ -7,5 +8,9 @@ namespace BuildingBlock.Identity.Contracts.Requests;
 /// </summary>
 /// <param name="RefreshToken">Refresh token value.</param>
 /// <param name="CorrelationId">Correlation identifier.</param>
-public sealed record RefreshIdentitySessionRequest(string RefreshToken, string CorrelationId)
+/// <param name="Provider">Auth provider used for the request.</param>
+public sealed record RefreshIdentitySessionRequest(
+    string RefreshToken,
+    string CorrelationId,
+    IdentityAuthProvider Provider = IdentityAuthProvider.InternalJwt)
     : IIdentityCapabilityContract;
diff --git a/src/BuildingBlock.Identity.Contracts/Responses/ExchangeIdentityProviderTokenResponse.cs b/src/BuildingBlock.Identity.Contracts/Responses/ExchangeIdentityProviderTokenResponse.cs
new file mode 100644
index 0000000..3ebee51
--- /dev/null
+++ b/src/BuildingBlock.Identity.Contracts/Responses/ExchangeIdentityProviderTokenResponse.cs
@@ -0,0 +1,17 @@
+using BuildingBlock.Identity.Contracts.Abstractions;
+using BuildingBlock.Identity.Contracts.Conventions;
+
+namespace BuildingBlock.Identity.Contracts.Responses;
+
+/// <summary>
+/// Returns token exchange result from an external provider token.
+/// </summary>
+/// <param name="SubjectId">Resolved identity subject identifier.</param>
+/// <param name="TenantId">Tenant identifier.</param>
+/// <param name="Provider">External identity provider.</param>
+/// <param name="IsAuthenticated">Whether provider token was accepted.</param>
+public sealed record ExchangeIdentityProviderTokenResponse(
+    string SubjectId,
+    string TenantId,
+    IdentityAuthProvider Provider,
+    bool IsAuthenticated) : IIdentityCapabilityContract;
diff --git a/tests/BuildingBlock.Identity.Contracts.UnitTests/ContractShapeTests.cs b/tests/BuildingBlock.Identity.Contracts.UnitTests/ContractShapeTests.cs
index 898e31d..fa0ab12 100644
--- a/tests/BuildingBlock.Identity.Contracts.UnitTests/ContractShapeTests.cs
+++ b/tests/BuildingBlock.Identity.Contracts.UnitTests/ContractShapeTests.cs
@@ -19,12 +19,33 @@ public class ContractShapeTests
     [Fact]
     public void IdentityContracts_WhenInstantiated_ImplementMarkerInterface()
     {
-        IIdentityCapabilityContract issueRequest = new IssueIdentityTokenRequest("subject-a", "tenant-a");
+        IIdentityCapabilityContract issueRequest = new IssueIdentityTokenRequest(
+            "subject-a",
+            "tenant-a",
+            IdentityAuthProvider.AzureAd,
+            "external-token");
         IIdentityCapabilityContract issueResponse = new IssueIdentityTokenResponse("token-a", 1800);
-        IIdentityCapabilityContract policyRequest = new EvaluateIdentityPolicyRequest("subject-b", "tenant-b", "identity.token.issue");
+        IIdentityCapabilityContract policyRequest = new EvaluateIdentityPolicyRequest(
+            "subject-b",
+            "tenant-b",
+            "identity.token.issue",
+            IdentityAuthProvider.Google);
         IIdentityCapabilityContract policyResponse = new EvaluateIdentityPolicyResponse("subject-b", "identity.token.issue", true);
-        IIdentityCapabilityContract refreshRequest = new RefreshIdentitySessionRequest("refresh-a", "corr-refresh");
+        IIdentityCapabilityContract refreshRequest = new RefreshIdentitySessionRequest(
+            "refresh-a",
+            "corr-refresh",
+            IdentityAuthProvider.InternalJwt);
         IIdentityCapabilityContract refreshResponse = new RefreshIdentitySessionResponse("token-b", 900);
+        IIdentityCapabilityContract exchangeRequest = new ExchangeIdentityProviderTokenRequest(
+            "tenant-c",
+            IdentityAuthProvider.AzureAd,
+            "provider-token",
+            "corr-exchange");
+        IIdentityCapabilityContract exchangeResponse = new ExchangeIdentityProviderTokenResponse(
+            "subject-c",
+            "tenant-c",
+            IdentityAuthProvider.AzureAd,
+            true);
 
         Assert.NotNull(issueRequest);
         Assert.NotNull(issueResponse);
@@ -32,5 +53,20 @@ public class ContractShapeTests
         Assert.NotNull(policyResponse);
         Assert.NotNull(refreshRequest);
         Assert.NotNull(refreshResponse);
+        Assert.NotNull(exchangeRequest);
+        Assert.NotNull(exchangeResponse);
+    }
+
+    [Fact]
+    public void IssueIdentityTokenRequest_WhenProviderSpecified_PreservesProviderMetadata()
+    {
+        var request = new IssueIdentityTokenRequest(
+            "subject-1",
+            "tenant-1",
+            IdentityAuthProvider.Google,
+            "google-token");
+
+        Assert.Equal(IdentityAuthProvider.Google, request.Provider);
+        Assert.Equal("google-token", request.ExternalToken);
     }
 }