diff --git a/.opencode/plugins/chainloop-trace.ts b/.opencode/plugins/chainloop-trace.ts
new file mode 100644
index 000000000..d6700243d
--- /dev/null
+++ b/.opencode/plugins/chainloop-trace.ts
@@ -0,0 +1,52 @@
+import type { Plugin } from "@opencode-ai/plugin"
+
+export const ChainloopTrace: Plugin = async ({ $ }) => {
+  // The commit-msg hook links sessions to commits by cross-referencing
+  // staged files against AI line attributions recorded by post-tool-use.
+  // If no file-writing tools (edit, write, apply_patch) are invoked during
+  // the session, there will be no attributions and the commit will not be
+  // marked as AI-assisted.
+  const fileWritingTools = ["edit","write","apply_patch"]
+
+  function filePathFromArgs(args: any): string {
+    if (args?.filePath) return args.filePath
+    if (args?.path) return args.path
+    return ""
+  }
+
+  async function fire(event: string, payload: Record<string, any>) {
+    const json = JSON.stringify(payload)
+    await $`echo ${json} | chainloop trace hook opencode ${event}`
+  }
+
+  return {
+    event: async ({ event }) => {
+      if (event.type === "session.created") {
+        const sessionID = event.properties?.info?.id ?? ""
+        await fire("session-start", { session_id: sessionID, hook_event_name: "session.created" })
+      }
+      if (event.type === "session.deleted") {
+        const sessionID = event.properties?.info?.id ?? ""
+        await fire("session-end", { session_id: sessionID, hook_event_name: "session.deleted" })
+      }
+    },
+    "tool.execute.before": async (input, output) => {
+      if (!fileWritingTools.includes(input.tool)) return
+      await fire("pre-tool-use", {
+        session_id: input.sessionID,
+        hook_event_name: "tool.execute.before",
+        tool_name: input.tool,
+        file_path: filePathFromArgs(output.args),
+      })
+    },
+    "tool.execute.after": async (input) => {
+      if (!fileWritingTools.includes(input.tool)) return
+      await fire("post-tool-use", {
+        session_id: input.sessionID,
+        hook_event_name: "tool.execute.after",
+        tool_name: input.tool,
+        file_path: filePathFromArgs(input.args),
+      })
+    },
+  }
+}