diff --git a/src/GameCult.Networking/Contracts/cultnet.witness-artifact-bundle.schema.json b/src/GameCult.Networking/Contracts/cultnet.witness-artifact-bundle.schema.json
new file mode 100644
index 00000000..a9cfbcef
--- /dev/null
+++ b/src/GameCult.Networking/Contracts/cultnet.witness-artifact-bundle.schema.json
@@ -0,0 +1,120 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://github.com/GameCult/cultnet-ts/contracts/cultnet.witness-artifact-bundle.schema.json",
+  "title": "CultNet Witness Artifact Bundle",
+  "type": "object",
+  "required": [
+    "bundleId",
+    "witnessKind",
+    "capturedAt",
+    "subject",
+    "contracts",
+    "artifacts",
+    "timingWitnesses",
+    "provenance"
+  ],
+  "additionalProperties": false,
+  "properties": {
+    "bundleId": { "type": "string", "minLength": 1 },
+    "witnessKind": { "type": "string", "minLength": 1 },
+    "capturedAt": { "type": "string", "minLength": 1 },
+    "subject": { "$ref": "#/$defs/subject_pin" },
+    "contracts": {
+      "type": "array",
+      "minItems": 1,
+      "items": { "$ref": "#/$defs/contract_pin" }
+    },
+    "artifacts": {
+      "type": "array",
+      "minItems": 1,
+      "items": { "$ref": "#/$defs/artifact_entry" }
+    },
+    "timingWitnesses": {
+      "type": "array",
+      "items": { "$ref": "#/$defs/timing_entry" }
+    },
+    "provenance": { "$ref": "#/$defs/provenance" }
+  },
+  "$defs": {
+    "subject_pin": {
+      "type": "object",
+      "required": [
+        "documentType",
+        "subjectId"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "documentType": { "type": "string", "minLength": 1 },
+        "subjectId": { "type": "string", "minLength": 1 },
+        "schemaVersion": { "type": "string", "minLength": 1 },
+        "schemaId": { "type": "string", "minLength": 1 },
+        "contentHash": { "type": "string", "minLength": 1 }
+      }
+    },
+    "contract_pin": {
+      "type": "object",
+      "required": [
+        "role",
+        "schemaId"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "role": { "type": "string", "minLength": 1 },
+        "schemaId": { "type": "string", "minLength": 1 },
+        "schemaVersion": { "type": "string", "minLength": 1 },
+        "contentHash": { "type": "string", "minLength": 1 }
+      }
+    },
+    "artifact_entry": {
+      "type": "object",
+      "required": [
+        "role",
+        "uri",
+        "mediaType"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "role": { "type": "string", "minLength": 1 },
+        "uri": { "type": "string", "minLength": 1 },
+        "mediaType": { "type": "string", "minLength": 1 },
+        "contentHash": { "type": "string", "minLength": 1 },
+        "byteLength": { "type": "integer", "minimum": 0 },
+        "producedAt": { "type": "string", "minLength": 1 }
+      }
+    },
+    "timing_entry": {
+      "type": "object",
+      "required": [
+        "stage",
+        "startedAt",
+        "completedAt",
+        "latencyMs"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "stage": { "type": "string", "minLength": 1 },
+        "startedAt": { "type": "string", "minLength": 1 },
+        "completedAt": { "type": "string", "minLength": 1 },
+        "latencyMs": { "type": "number", "minimum": 0 },
+        "witnessArtifactUri": { "type": "string", "minLength": 1 }
+      }
+    },
+    "provenance": {
+      "type": "object",
+      "required": [
+        "pipelineId",
+        "runId",
+        "runtimeId"
+      ],
+      "additionalProperties": false,
+      "properties": {
+        "pipelineId": { "type": "string", "minLength": 1 },
+        "runId": { "type": "string", "minLength": 1 },
+        "runtimeId": { "type": "string", "minLength": 1 },
+        "agentId": { "type": "string", "minLength": 1 },
+        "agentRole": { "type": "string", "minLength": 1 },
+        "toolVersion": { "type": "string", "minLength": 1 }
+      }
+    }
+  }
+}
diff --git a/src/GameCult.Networking/CultNetSchemaMessages.cs b/src/GameCult.Networking/CultNetSchemaMessages.cs
index fc21f5ee..18b6f9ef 100644
--- a/src/GameCult.Networking/CultNetSchemaMessages.cs
+++ b/src/GameCult.Networking/CultNetSchemaMessages.cs
@@ -116,6 +116,10 @@ namespace GameCult.Networking
         /// </summary>
         public const string SimulationConsensusCandidate = "cultnet.simulation_consensus_candidate.v0";
         /// <summary>
+        /// witness artifact bundle document contract identifier.
+        /// </summary>
+        public const string WitnessArtifactBundle = "cultnet.witness_artifact_bundle.v0";
+        /// <summary>
         /// CultMesh Verse catalog request contract identifier.
         /// </summary>
         public const string VerseCatalogRequest = "cultmesh.verse_catalog_request.v0";
diff --git a/src/GameCult.Networking/CultNetSchemaRegistry.cs b/src/GameCult.Networking/CultNetSchemaRegistry.cs
index 025afa3f..10f216ec 100644
--- a/src/GameCult.Networking/CultNetSchemaRegistry.cs
+++ b/src/GameCult.Networking/CultNetSchemaRegistry.cs
@@ -375,6 +375,14 @@ namespace GameCult.Networking
                 SchemaVersion = "ghostlight.agent_state.v0",
                 DocumentType = "ghostlight.agent-state",
                 WireContracts = new[] { CultNetWireContracts.SchemaV0 }
+            },
+            new SchemaResourceSpec
+            {
+                FileName = "cultnet.witness-artifact-bundle.schema.json",
+                Kind = "document_payload",
+                SchemaVersion = CultNetSchemaVersions.WitnessArtifactBundle,
+                DocumentType = "cultnet.witness-artifact-bundle",
+                WireContracts = new[] { CultNetWireContracts.SchemaV0 }
             }
         };
     }
diff --git a/src/GameCult.Networking/CultWitnessArtifactBundle.cs b/src/GameCult.Networking/CultWitnessArtifactBundle.cs
new file mode 100644
index 00000000..045ebfbb
--- /dev/null
+++ b/src/GameCult.Networking/CultWitnessArtifactBundle.cs
@@ -0,0 +1,254 @@
+using System;
+using GameCult.Caching;
+using MessagePack;
+
+namespace GameCult.Networking
+{
+    /// <summary>
+    /// Portable manifest for one inspectable pipeline witness bundle.
+    /// </summary>
+    [MessagePackObject]
+    [CultDocument("cultnet.witness_artifact_bundle", CultNetSchemaVersions.WitnessArtifactBundle)]
+    public sealed class CultWitnessArtifactBundle
+    {
+        /// <summary>
+        /// Gets or sets the stable bundle identifier.
+        /// </summary>
+        [Key(0)]
+        [CultName]
+        public string BundleId { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the witness family or pipeline kind.
+        /// </summary>
+        [Key(1)]
+        public string WitnessKind { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets when the manifest was captured.
+        /// </summary>
+        [Key(2)]
+        public string CapturedAt { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the pinned subject this witness bundle describes.
+        /// </summary>
+        [Key(3)]
+        public CultWitnessSubjectPin Subject { get; set; } = new CultWitnessSubjectPin();
+
+        /// <summary>
+        /// Gets or sets the schema and contract pins required to interpret the witness.
+        /// </summary>
+        [Key(4)]
+        public CultWitnessContractPin[] Contracts { get; set; } = Array.Empty<CultWitnessContractPin>();
+
+        /// <summary>
+        /// Gets or sets the inspectable artifact pointers carried by the bundle.
+        /// </summary>
+        [Key(5)]
+        public CultWitnessArtifactEntry[] Artifacts { get; set; } = Array.Empty<CultWitnessArtifactEntry>();
+
+        /// <summary>
+        /// Gets or sets stage timing witnesses associated with the bundle.
+        /// </summary>
+        [Key(6)]
+        public CultWitnessTimingEntry[] TimingWitnesses { get; set; } = Array.Empty<CultWitnessTimingEntry>();
+
+        /// <summary>
+        /// Gets or sets provenance metadata for the bundle producer.
+        /// </summary>
+        [Key(7)]
+        public CultWitnessProvenance Provenance { get; set; } = new CultWitnessProvenance();
+    }
+
+    /// <summary>
+    /// Pins the document or payload instance the witness is about.
+    /// </summary>
+    [MessagePackObject]
+    public sealed class CultWitnessSubjectPin
+    {
+        /// <summary>
+        /// Gets or sets the subject document type or domain identifier.
+        /// </summary>
+        [Key(0)]
+        public string DocumentType { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the persisted record key or equivalent stable subject id.
+        /// </summary>
+        [Key(1)]
+        public string SubjectId { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the pinned subject schema version.
+        /// </summary>
+        [Key(2)]
+        public string? SchemaVersion { get; set; }
+
+        /// <summary>
+        /// Gets or sets the pinned subject schema identifier when one exists.
+        /// </summary>
+        [Key(3)]
+        public string? SchemaId { get; set; }
+
+        /// <summary>
+        /// Gets or sets the pinned subject content hash when one exists.
+        /// </summary>
+        [Key(4)]
+        public string? ContentHash { get; set; }
+    }
+
+    /// <summary>
+    /// Pins one schema or contract dependency for the witness bundle.
+    /// </summary>
+    [MessagePackObject]
+    public sealed class CultWitnessContractPin
+    {
+        /// <summary>
+        /// Gets or sets the contract role inside the bundle.
+        /// </summary>
+        [Key(0)]
+        public string Role { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the stable schema identifier.
+        /// </summary>
+        [Key(1)]
+        public string SchemaId { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the pinned schema version.
+        /// </summary>
+        [Key(2)]
+        public string? SchemaVersion { get; set; }
+
+        /// <summary>
+        /// Gets or sets the canonical schema content hash when one exists.
+        /// </summary>
+        [Key(3)]
+        public string? ContentHash { get; set; }
+    }
+
+    /// <summary>
+    /// Points at one inspectable artifact emitted by the witnessed pipeline.
+    /// </summary>
+    [MessagePackObject]
+    public sealed class CultWitnessArtifactEntry
+    {
+        /// <summary>
+        /// Gets or sets the artifact role inside the witness bundle.
+        /// </summary>
+        [Key(0)]
+        public string Role { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the portable URI for the artifact.
+        /// </summary>
+        [Key(1)]
+        public string Uri { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the artifact media type.
+        /// </summary>
+        [Key(2)]
+        public string MediaType { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the artifact content hash when one exists.
+        /// </summary>
+        [Key(3)]
+        public string? ContentHash { get; set; }
+
+        /// <summary>
+        /// Gets or sets the artifact size in bytes when known.
+        /// </summary>
+        [Key(4)]
+        public long? ByteLength { get; set; }
+
+        /// <summary>
+        /// Gets or sets when the artifact was produced.
+        /// </summary>
+        [Key(5)]
+        public string? ProducedAt { get; set; }
+    }
+
+    /// <summary>
+    /// Records timestamp and latency evidence for one stage in the witnessed pipeline.
+    /// </summary>
+    [MessagePackObject]
+    public sealed class CultWitnessTimingEntry
+    {
+        /// <summary>
+        /// Gets or sets the pipeline stage name.
+        /// </summary>
+        [Key(0)]
+        public string Stage { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets when the stage started.
+        /// </summary>
+        [Key(1)]
+        public string StartedAt { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets when the stage completed.
+        /// </summary>
+        [Key(2)]
+        public string CompletedAt { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the observed stage latency in milliseconds.
+        /// </summary>
+        [Key(3)]
+        public double LatencyMs { get; set; }
+
+        /// <summary>
+        /// Gets or sets the URI for the timing witness artifact when one exists.
+        /// </summary>
+        [Key(4)]
+        public string? WitnessArtifactUri { get; set; }
+    }
+
+    /// <summary>
+    /// Carries provenance metadata for the witness bundle producer.
+    /// </summary>
+    [MessagePackObject]
+    public sealed class CultWitnessProvenance
+    {
+        /// <summary>
+        /// Gets or sets the stable pipeline identifier.
+        /// </summary>
+        [Key(0)]
+        public string PipelineId { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the pipeline run identifier.
+        /// </summary>
+        [Key(1)]
+        public string RunId { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the runtime identifier that produced the bundle.
+        /// </summary>
+        [Key(2)]
+        public string RuntimeId { get; set; } = string.Empty;
+
+        /// <summary>
+        /// Gets or sets the producing agent identifier when one exists.
+        /// </summary>
+        [Key(3)]
+        public string? AgentId { get; set; }
+
+        /// <summary>
+        /// Gets or sets the producing agent role when one exists.
+        /// </summary>
+        [Key(4)]
+        public string? AgentRole { get; set; }
+
+        /// <summary>
+        /// Gets or sets the pipeline or tool version when one exists.
+        /// </summary>
+        [Key(5)]
+        public string? ToolVersion { get; set; }
+    }
+}
diff --git a/tests/GameCult.Networking.Tests/NetworkingTests.cs b/tests/GameCult.Networking.Tests/NetworkingTests.cs
index 381ffaf0..25a5d4b6 100644
--- a/tests/GameCult.Networking.Tests/NetworkingTests.cs
+++ b/tests/GameCult.Networking.Tests/NetworkingTests.cs
@@ -2286,6 +2286,39 @@ namespace GameCult.Networking.Tests
             Assert.That(ghostlight.Kind, Is.EqualTo("document_payload"));
         }
 
+        [Test]
+        public void CultWitnessArtifactBundle_Has_Stable_CacheContract()
+        {
+            var descriptor = new CultCache().Registry.GetRequired<CultWitnessArtifactBundle>();
+
+            Assert.That(descriptor.SchemaName, Is.EqualTo("cultnet.witness_artifact_bundle"));
+            Assert.That(descriptor.SchemaVersion, Is.EqualTo(CultNetSchemaVersions.WitnessArtifactBundle));
+            Assert.That(descriptor.NameMember, Is.EqualTo(nameof(CultWitnessArtifactBundle.BundleId)));
+            Assert.That(descriptor.CanonicalSchemaJson, Is.EqualTo(
+                "{\"schemaName\":\"cultnet.witness_artifact_bundle\",\"schemaVersion\":\"cultnet.witness_artifact_bundle.v0\",\"members\":[{\"slot\":0,\"name\":\"BundleId\",\"type\":\"System.String\",\"isReference\":false,\"many\":false,\"targetSchemaName\":null,\"indexAlias\":null,\"isName\":true},{\"slot\":1,\"name\":\"WitnessKind\",\"type\":\"System.String\",\"isReference\":false,\"many\":false,\"targetSchemaName\":null,\"indexAlias\":null,\"isName\":false},{\"slot\":2,\"name\":\"CapturedAt\",\"type\":\"System.String\",\"isReference\":false,\"many\":false,\"targetSchemaName\":null,\"indexAlias\":null,\"isName\":false},{\"slot\":3,\"name\":\"Subject\",\"type\":\"GameCult.Networking.CultWitnessSubjectPin\",\"isReference\":false,\"many\":false,\"targetSchemaName\":null,\"indexAlias\":null,\"isName\":false},{\"slot\":4,\"name\":\"Contracts\",\"type\":\"GameCult.Networking.CultWitnessContractPin[]\",\"isReference\":false,\"many\":false,\"targetSchemaName\":null,\"indexAlias\":null,\"isName\":false},{\"slot\":5,\"name\":\"Artifacts\",\"type\":\"GameCult.Networking.CultWitnessArtifactEntry[]\",\"isReference\":false,\"many\":false,\"targetSchemaName\":null,\"indexAlias\":null,\"isName\":false},{\"slot\":6,\"name\":\"TimingWitnesses\",\"type\":\"GameCult.Networking.CultWitnessTimingEntry[]\",\"isReference\":false,\"many\":false,\"targetSchemaName\":null,\"indexAlias\":null,\"isName\":false},{\"slot\":7,\"name\":\"Provenance\",\"type\":\"GameCult.Networking.CultWitnessProvenance\",\"isReference\":false,\"many\":false,\"targetSchemaName\":null,\"indexAlias\":null,\"isName\":false}]}"));
+        }
+
+        [Test]
+        public void CultNetSchemaRegistry_BuiltInCatalog_Advertises_WitnessArtifactBundle()
+        {
+            var response = CultNetSchemaRegistry.BuiltIn.CreateCatalogResponse(
+                new CultNetSchemaCatalogRequestMessage
+                {
+                    MessageId = "catalog-witness",
+                    IncludeSchemaJson = true
+                });
+            var witnessBundle = Array.Find(response.Schemas,
+                schema => schema.SchemaVersion == CultNetSchemaVersions.WitnessArtifactBundle);
+
+            Assert.That(witnessBundle, Is.Not.Null);
+            Assert.That(witnessBundle!.DocumentType, Is.EqualTo("cultnet.witness-artifact-bundle"));
+            Assert.That(witnessBundle.Kind, Is.EqualTo("document_payload"));
+            Assert.That(witnessBundle.WireContracts, Is.EqualTo([CultNetWireContracts.SchemaV0]));
+            Assert.That(witnessBundle.SchemaJson, Does.Contain("\"bundleId\""));
+            Assert.That(witnessBundle.SchemaJson, Does.Contain("\"timingWitnesses\""));
+            Assert.That(witnessBundle.SchemaJson, Does.Contain("\"witnessArtifactUri\""));
+        }
+
         [Test]
         public void Server_Separates_Connection_And_Auth_RateLimits()
         {