diff --git a/.github/plugin/marketplace.json b/.github/plugin/marketplace.json
index e60197b74..ee94ffb11 100644
--- a/.github/plugin/marketplace.json
+++ b/.github/plugin/marketplace.json
@@ -1627,6 +1627,37 @@
       "description": "Plain-English translation layer for non-technical Copilot CLI users. Translates every approval prompt, error message, and technical output into clear, jargon-free English with color-coded risk indicators.",
       "version": "1.0.0"
     },
+    {
+      "name": "oddyssey",
+      "description": "Observability-Driven Development for coding agents: an OpenTelemetry instrumentation expert, a run-observation agent that measures a service through its telemetry on a local Grafana stack or a remote backend (Grafana, Datadog, Dynatrace, Azure Monitor, CloudWatch), a verification pass that replays a stored run, k6 benchmark authoring, and a committed .odd/ memory that carries the loop across runs.",
+      "version": "1.12.1",
+      "author": {
+        "name": "using-system",
+        "url": "https://github.com/using-system"
+      },
+      "repository": "https://github.com/using-system/oddyssey",
+      "homepage": "https://github.com/using-system/oddyssey#readme",
+      "license": "MIT",
+      "keywords": [
+        "observability",
+        "opentelemetry",
+        "grafana",
+        "k6",
+        "mcp",
+        "ai-agents",
+        "developer-tools",
+        "performance",
+        "telemetry",
+        "load-testing"
+      ],
+      "source": {
+        "source": "github",
+        "repo": "using-system/oddyssey",
+        "path": "marketplace/oddyssey",
+        "ref": "v1.12.1",
+        "sha": "407c8e2248c12e112098861a9c577027708ba031"
+      }
+    },
     {
       "name": "openapi-to-application-csharp-dotnet",
       "source": "plugins/openapi-to-application-csharp-dotnet",
diff --git a/plugins/external.json b/plugins/external.json
index bba56c9ae..7ae2aad62 100644
--- a/plugins/external.json
+++ b/plugins/external.json
@@ -1287,6 +1287,37 @@
       "sha": "e10cd19c000651620453e99ed138b8f012d069c7"
     }
   },
+  {
+    "name": "oddyssey",
+    "description": "Observability-Driven Development for coding agents: an OpenTelemetry instrumentation expert, a run-observation agent that measures a service through its telemetry on a local Grafana stack or a remote backend (Grafana, Datadog, Dynatrace, Azure Monitor, CloudWatch), a verification pass that replays a stored run, k6 benchmark authoring, and a committed .odd/ memory that carries the loop across runs.",
+    "version": "1.12.1",
+    "author": {
+      "name": "using-system",
+      "url": "https://github.com/using-system"
+    },
+    "repository": "https://github.com/using-system/oddyssey",
+    "homepage": "https://github.com/using-system/oddyssey#readme",
+    "license": "MIT",
+    "keywords": [
+      "observability",
+      "opentelemetry",
+      "grafana",
+      "k6",
+      "mcp",
+      "ai-agents",
+      "developer-tools",
+      "performance",
+      "telemetry",
+      "load-testing"
+    ],
+    "source": {
+      "source": "github",
+      "repo": "using-system/oddyssey",
+      "path": "marketplace/oddyssey",
+      "ref": "v1.12.1",
+      "sha": "407c8e2248c12e112098861a9c577027708ba031"
+    }
+  },
   {
     "name": "pm-skills",
     "description": "MCP server and 12 skills for product analysis, specification writing, strategy, narrative, and stakeholder alignment. Run competitive analyses, write zero-question specs, design metrics, and produce executive-ready documents directly from Copilot.",