feat: tag traces with skill:<name> when a SKILL.md is read by a tool call

plugins/tracing/dist/index.mjs

@@ -47116,6 +47116,26 @@ function emitToolCall(tc, parent, clip, fallbackEnd) {
 		parentSpanContext: parent.otelSpan.spanContext()
 	}).end(new Date(tc.endTime ?? fallbackEnd));
 }
+const SKILL_MD_PATH_RE = /(?:^|[\s"'`=(/])skills\/([A-Za-z0-9_.-]+)\/SKILL\.md/g;
+/**
+* Collect `skill:<name>` tags for every skill whose SKILL.md was read by a
+* tool call in this turn. Mirrors the Claude Code plugin's skill tags so the
+* two projects share the same tag semantics: `skill:` means "read in the
+* top-level conversation". Subagent rollouts are intentionally out of scope
+* (the Claude plugin keeps those in a separate `subagent-skill:` namespace;
+* add the equivalent here if subagent skill reads become worth tracking).
+*/
+function collectSkillTags(turn) {
+	const tags = [];
+	for (const step of turn.steps) for (const call of step.toolCalls) {
+		const raw = typeof call.args === "string" ? call.args : toText(call.args ?? "");
+		for (const match of raw.matchAll(SKILL_MD_PATH_RE)) {
+			const tag = `skill:${match[1]}`;
+			if (!tags.includes(tag)) tags.push(tag);
+		}
+	}
+	return tags;
+}
 /**
 * Convert a Codex rollout file into Langfuse traces.
 *
@@ -47139,11 +47159,12 @@ async function convertRollout(rolloutFile, options) {
 		const turn = turns[turnIndex];
 		if (turn.completed && turn.turnId && uploaded.has(turn.turnId)) continue;
 		const seededParent = await seededTraceParent(options.config, sessionMeta, turnIndex + 1);
+		const tags = [...options.config.tags ?? [], ...collectSkillTags(turn)];
 		await propagateAttributes({
 			sessionId: sessionMeta.sessionId,
 			traceName: sessionMeta.isSubagentThread ? "Codex Subagent Turn" : "Codex Turn",
 			...options.config.user_id ? { userId: options.config.user_id } : {},
-			...options.config.tags ? { tags: options.config.tags } : {},
+			...tags.length ? { tags } : {},
 			...options.config.metadata ? { metadata: options.config.metadata } : {}
 		}, async () => {
 			await emitTurn(turn, sessionMeta, {

plugins/tracing/src/trace.ts

@@ -320,6 +320,32 @@ function emitToolCall(
   tool.end(new Date(tc.endTime ?? fallbackEnd));
 }
 
+// Matches a skill's SKILL.md path anywhere inside tool-call arguments (shell
+// commands read skills as e.g. `cat ~/.codex/skills/<name>/SKILL.md`).
+const SKILL_MD_PATH_RE = /(?:^|[\s"'`=(/])skills\/([A-Za-z0-9_.-]+)\/SKILL\.md/g;
+
+/**
+ * Collect `skill:<name>` tags for every skill whose SKILL.md was read by a
+ * tool call in this turn. Mirrors the Claude Code plugin's skill tags so the
+ * two projects share the same tag semantics: `skill:` means "read in the
+ * top-level conversation". Subagent rollouts are intentionally out of scope
+ * (the Claude plugin keeps those in a separate `subagent-skill:` namespace;
+ * add the equivalent here if subagent skill reads become worth tracking).
+ */
+export function collectSkillTags(turn: Turn): string[] {
+  const tags: string[] = [];
+  for (const step of turn.steps) {
+    for (const call of step.toolCalls) {
+      const raw = typeof call.args === "string" ? call.args : toText(call.args ?? "");
+      for (const match of raw.matchAll(SKILL_MD_PATH_RE)) {
+        const tag = `skill:${match[1]}`;
+        if (!tags.includes(tag)) tags.push(tag);
+      }
+    }
+  }
+  return tags;
+}
+
 /**
  * Convert a Codex rollout file into Langfuse traces.
  *
@@ -358,12 +384,13 @@ export async function convertRollout(
     // skipped by dedup above) so the derived id is stable across hook runs.
     const seededParent = await seededTraceParent(options.config, sessionMeta, turnIndex + 1);
 
+    const tags = [...(options.config.tags ?? []), ...collectSkillTags(turn)];
     await propagateAttributes(
       {
         sessionId: sessionMeta.sessionId,
         traceName: sessionMeta.isSubagentThread ? "Codex Subagent Turn" : "Codex Turn",
         ...(options.config.user_id ? { userId: options.config.user_id } : {}),
-        ...(options.config.tags ? { tags: options.config.tags } : {}),
+        ...(tags.length ? { tags } : {}),
         ...(options.config.metadata ? { metadata: options.config.metadata } : {}),
       },
       async () => {

plugins/tracing/test/trace.test.ts

@@ -13,7 +13,7 @@ import { NodeTracerProvider } from "@opentelemetry/sdk-trace-node";
 import { afterAll, beforeAll, beforeEach, describe, expect, it } from "vitest";
 
 import type { Config } from "../src/config.js";
-import { convertRollout } from "../src/trace.js";
+import { collectSkillTags, convertRollout } from "../src/trace.js";
 
 const exporter = new InMemorySpanExporter();
 let provider: NodeTracerProvider;
@@ -330,3 +330,50 @@ describe("deterministic trace ids (trace_seed)", () => {
     expect(roots[0].spanContext().traceId).toBe(seededTraceId(`${seed}:2`));
   });
 });
+
+describe("collectSkillTags", () => {
+  const makeTurn = (calls: unknown[]): Parameters<typeof collectSkillTags>[0] =>
+    ({
+      startTime: 0,
+      endTime: 1,
+      steps: [
+        {
+          startTime: 0,
+          endTime: 1,
+          toolCalls: calls.map((args, i) => ({
+            callId: `c${i}`,
+            name: "shell",
+            args,
+            startTime: 0,
+          })),
+        },
+      ],
+      subagentThreadIds: [],
+      completed: true,
+      aborted: false,
+    }) as Parameters<typeof collectSkillTags>[0];
+
+  it("tags a SKILL.md read from shell command args", () => {
+    const turn = makeTurn([
+      { command: ["bash", "-lc", "cat /Users/u/.codex/skills/goal-first/SKILL.md"] },
+    ]);
+    expect(collectSkillTags(turn)).toEqual(["skill:goal-first"]);
+  });
+
+  it("dedupes repeated reads and collects multiple skills", () => {
+    const turn = makeTurn([
+      { command: ["cat", "/home/u/dotfiles/codex/skills/goal-first/SKILL.md"] },
+      { command: ["sed", "-n", "1,40p", "skills/goal-first/SKILL.md"] },
+      { command: ["cat", "skills/structured-answer/SKILL.md"] },
+    ]);
+    expect(collectSkillTags(turn)).toEqual(["skill:goal-first", "skill:structured-answer"]);
+  });
+
+  it("ignores non-SKILL.md paths and unrelated commands", () => {
+    const turn = makeTurn([
+      { command: ["cat", "skills/goal-first/references/deep.md"] },
+      { command: ["ls", "src/"] },
+    ]);
+    expect(collectSkillTags(turn)).toEqual([]);
+  });
+});