diff --git a/internal/cloud/access-control.ts b/internal/cloud/access-control.ts
index 39465d7b..a00e172b 100644
--- a/internal/cloud/access-control.ts
+++ b/internal/cloud/access-control.ts
@@ -204,8 +204,7 @@ class AccessController {
         return;
       }
       if (request.method === "GET" && url.pathname === "/auth/session") {
-        const payload = await this.sessionPayload(request);
-        sendJson(response, payload.authenticated ? 200 : 401, payload);
+        await this.handleSessionRoute(request, response);
         return;
       }
 
@@ -386,6 +385,47 @@ class AccessController {
     return sessionResponseFromAuth(auth, { setupRequired });
   }
 
+  async handleSessionRoute(request, response) {
+    const otelContext = authLoginOtelTraceContext({ traceparent: getHeader(request, "traceparent") });
+    setAuthTraceHeaders(response, otelContext);
+    const startedAtMs = Date.now();
+    let httpStatus = 500;
+    let outcome = "error";
+    let errorCode = "";
+    try {
+      const payload = await this.sessionPayload(request);
+      httpStatus = payload.authenticated ? 200 : 401;
+      outcome = payload.authenticated ? "authenticated" : "unauthenticated";
+      errorCode = payload.error?.code ? textOr(payload.error.code, "") : "";
+      sendJson(response, httpStatus, payload);
+      return;
+    } catch (error) {
+      httpStatus = Number(error?.statusCode ?? error?.status ?? httpStatus ?? 500);
+      errorCode = textOr(error?.code, "auth_session_error");
+      throw error;
+    } finally {
+      void emitAuthOtelSpan("auth.session", otelContext, this.env, {
+        spanId: otelContext.rootSpanId,
+        parentSpanId: otelContext.parentSpanId,
+        kind: 2,
+        startTimeMs: startedAtMs,
+        endTimeMs: Date.now(),
+        status: httpStatus >= 500 ? "error" : "ok",
+        error: httpStatus >= 500 || (errorCode && httpStatus >= 500) ? new Error(errorCode || "auth_session_error") : null,
+        attributes: {
+          "http.method": "GET",
+          "http.route": "/auth/session",
+          "http.status_code": httpStatus,
+          "auth.outcome": outcome,
+          "auth.authenticated": outcome === "authenticated",
+          "auth.trace_visible": true,
+          "auth.values_redacted": true,
+          ...(errorCode ? { "error.code": errorCode } : {})
+        }
+      });
+    }
+  }
+
   async accessStatusPayload(request) {
     const session = await this.sessionPayload(request);
     return {
@@ -1142,14 +1182,52 @@ class AccessController {
   }
 
   async handleLogout(request, response) {
+    const otelContext = authLoginOtelTraceContext({ traceparent: getHeader(request, "traceparent") });
+    setAuthTraceHeaders(response, otelContext);
+    const startedAtMs = Date.now();
     const token = sessionCookieFromRequest(request);
-    if (token?.startsWith("hws_") && this.userBilling?.configured && typeof this.userBilling.logout === "function") {
-      await this.userBilling.logout(token);
-    } else if (token) {
-      await this.store.revokeSessionByTokenHash(sha256(token), this.now());
+    let httpStatus = 500;
+    let outcome = "error";
+    let errorCode = "";
+    try {
+      if (token?.startsWith("hws_") && this.userBilling?.configured && typeof this.userBilling.logout === "function") {
+        await this.userBilling.logout(token);
+        outcome = "user_billing_session";
+      } else if (token) {
+        await this.store.revokeSessionByTokenHash(sha256(token), this.now());
+        outcome = "local_session";
+      } else {
+        outcome = "no_session_cookie";
+      }
+      clearSessionCookie(response, request, this.env);
+      httpStatus = 200;
+      return sendJson(response, 200, { authenticated: false, loggedOut: true });
+    } catch (error) {
+      httpStatus = Number(error?.statusCode ?? error?.status ?? httpStatus ?? 500);
+      errorCode = textOr(error?.code, "auth_logout_error");
+      throw error;
+    } finally {
+      void emitAuthOtelSpan("auth.logout", otelContext, this.env, {
+        spanId: otelContext.rootSpanId,
+        parentSpanId: otelContext.parentSpanId,
+        kind: 2,
+        startTimeMs: startedAtMs,
+        endTimeMs: Date.now(),
+        status: httpStatus >= 500 || errorCode ? "error" : "ok",
+        error: errorCode ? new Error(errorCode) : null,
+        attributes: {
+          "http.method": "POST",
+          "http.route": "/auth/logout",
+          "http.status_code": httpStatus,
+          "auth.outcome": outcome,
+          "auth.cookie_present": Boolean(token),
+          "auth.user_billing_token": Boolean(token?.startsWith("hws_")),
+          "auth.trace_visible": true,
+          "auth.values_redacted": true,
+          ...(errorCode ? { "error.code": errorCode } : {})
+        }
+      });
     }
-    clearSessionCookie(response, request, this.env);
-    return sendJson(response, 200, { authenticated: false, loggedOut: true });
   }
 
   async codeAgentToolCapabilitiesForOwner(ownerUserId) {
diff --git a/internal/cloud/server-workbench-http.ts b/internal/cloud/server-workbench-http.ts
index 8795bc01..3ce62a16 100644
--- a/internal/cloud/server-workbench-http.ts
+++ b/internal/cloud/server-workbench-http.ts
@@ -16,7 +16,7 @@ import {
 import { createWorkbenchReadModel } from "./workbench-read-model.ts";
 import { createWorkbenchRuntimeClient } from "./workbench-runtime-client.ts";
 import { durableTraceStatus, RUNNING_STATUSES, TERMINAL_STATUSES } from "./workbench-turn-projection.ts";
-import { emitHttpServerRequestSpan } from "./otel-trace.ts";
+import { emitCodeAgentOtelSpan, emitHttpServerRequestSpan } from "./otel-trace.ts";
 
 const DEFAULT_PAGE_LIMIT = 50;
 const DEFAULT_SESSION_LIST_LIMIT = 20;
@@ -1682,6 +1682,13 @@ async function handleWorkbenchTurnSnapshot(request, response, url, options, acto
   const result = await readModel.queryFacts({ traceId, limit: MAX_PAGE_LIMIT, families: [...WORKBENCH_TRACE_EVENT_METADATA_FAMILIES, ...WORKBENCH_TRACE_EVENT_PAGE_FAMILIES] });
   if (result.error) {
     const body = workbenchProjectionStoreError(result.error);
+    emitWorkbenchTurnStatusReadOtel(traceId, options, {
+      startTimeMs: startedAt,
+      statusCode: 503,
+      phase: "query_failed",
+      turnId,
+      errorCode: result.error?.code ?? "workbench_turn_query_failed"
+    }, result.error);
     recordWorkbenchTurnReadMetric(options, url, 503, body, startedAt);
     return sendJson(response, 503, body);
   }
@@ -1691,6 +1698,14 @@ async function handleWorkbenchTurnSnapshot(request, response, url, options, acto
   if (!found) {
     const body = workbenchError("workbench_turn_not_found", "Workbench turn is not visible to the current actor.", { turnId, traceId });
     attachWorkbenchReadModelDiagnosticOtel(request, { route: "/v1/workbench/turns/:id", code: "workbench_turn_not_found", traceId, turnId, count: result.count });
+    emitWorkbenchTurnStatusReadOtel(traceId, options, {
+      startTimeMs: startedAt,
+      statusCode: 404,
+      phase: "not_found",
+      turnId,
+      readCount: result.count,
+      errorCode: "workbench_turn_not_found"
+    });
     recordWorkbenchTurnReadMetric(options, url, 404, body, startedAt);
     return sendJson(response, 404, body);
   }
@@ -1718,6 +1733,22 @@ async function handleWorkbenchTurnSnapshot(request, response, url, options, acto
     projection: { ...projection, status, eventCount: snapshot.trace?.eventCount ?? projection.lastProjectedSeq ?? 0 },
     diagnostic: projection
   });
+  emitWorkbenchTurnStatusReadOtel(traceId, options, {
+    startTimeMs: startedAt,
+    statusCode: 200,
+    phase: "succeeded",
+    status,
+    terminal: snapshot.terminal,
+    sessionId: snapshot.sessionId,
+    turnId: snapshot.turnId,
+    traceEventCount: snapshot.trace?.eventCount ?? null,
+    latestProjectedSeq: projection.lastProjectedSeq,
+    projectionStatus: projection.projectionStatus,
+    projectionHealth: projection.projectionHealth,
+    sourceRunId: projection.sourceRunId,
+    sourceCommandId: projection.sourceCommandId,
+    readCount: result.count
+  });
   recordWorkbenchTurnReadMetric(options, url, 200, body, startedAt);
   recordWorkbenchCacheMetric(options, url, body, startedAt);
   sendJson(response, 200, body);
@@ -1730,14 +1761,43 @@ async function handleWorkbenchTraceEventPage(request, response, url, options, ac
   const readModel = workbenchRuntimeFactsReadModel(request, options, actor);
   const pageOptions = tracePageOptions(url);
   const metadata = await readModel.queryFacts({ traceId, families: WORKBENCH_TRACE_EVENT_METADATA_FAMILIES, limit: 1 });
-  if (metadata.error) return sendJson(response, 503, workbenchProjectionStoreError(metadata.error));
+  if (metadata.error) {
+    emitWorkbenchTraceEventsReadOtel(traceId, options, {
+      startTimeMs: startedAt,
+      statusCode: 503,
+      phase: "metadata_query_failed",
+      pageOptions,
+      errorCode: metadata.error?.code ?? "workbench_trace_metadata_query_failed"
+    }, metadata.error);
+    return sendJson(response, 503, workbenchProjectionStoreError(metadata.error));
+  }
   const resolved = await visibleFactSessionForTrace(readModel, metadata.facts, actor, traceId);
-  if (resolved.error) return sendJson(response, 503, workbenchProjectionStoreError(resolved.error));
+  if (resolved.error) {
+    emitWorkbenchTraceEventsReadOtel(traceId, options, {
+      startTimeMs: startedAt,
+      statusCode: 503,
+      phase: "session_lookup_failed",
+      pageOptions,
+      metadataCount: metadata.count,
+      errorCode: resolved.error?.code ?? "workbench_trace_session_lookup_failed"
+    }, resolved.error);
+    return sendJson(response, 503, workbenchProjectionStoreError(resolved.error));
+  }
   const session = resolved.session;
   const metadataFacts = resolved.facts ?? metadata.facts;
   if (!session) {
     const context = await readModel.queryFacts({ traceId, families: ["sessions", "turns", "checkpoints"], limit: MAX_PAGE_LIMIT });
-    if (context.error) return sendJson(response, 503, workbenchProjectionStoreError(context.error));
+    if (context.error) {
+      emitWorkbenchTraceEventsReadOtel(traceId, options, {
+        startTimeMs: startedAt,
+        statusCode: 503,
+        phase: "context_query_failed",
+        pageOptions,
+        metadataCount: metadata.count,
+        errorCode: context.error?.code ?? "workbench_trace_context_query_failed"
+      }, context.error);
+      return sendJson(response, 503, workbenchProjectionStoreError(context.error));
+    }
     const contextSessions = visibleFactSessions(context.facts, actor);
     const contextSession = contextSessions.find((item) => item.lastTraceId === traceId) ?? contextSessions[0] ?? null;
     const contextTurn = factTurnForTrace(context.facts, traceId, traceId);
@@ -1745,14 +1805,47 @@ async function handleWorkbenchTraceEventPage(request, response, url, options, ac
       const projection = factProjectionForTrace(context.facts, traceId);
       const blocker = traceEventsReadModelBlocker("workbench_trace_metadata_missing", "Workbench trace metadata is missing from the trace events read model.", { traceId, projection, session: contextSession, turn: contextTurn, route: url.pathname });
       attachWorkbenchReadModelDiagnosticOtel(request, { route: "/v1/workbench/traces/:id/events", code: "workbench_trace_metadata_missing", sessionId: factSessionId(contextSession), traceId, count: context.count });
+      emitWorkbenchTraceEventsReadOtel(traceId, options, {
+        startTimeMs: startedAt,
+        statusCode: 404,
+        phase: "metadata_missing",
+        pageOptions,
+        projection,
+        sessionId: factSessionId(contextSession),
+        turnId: factTurnId(contextTurn, traceId),
+        readCount: context.count,
+        metadataCount: metadata.count,
+        errorCode: "workbench_trace_metadata_missing"
+      });
       return sendJson(response, 404, workbenchTraceEventsReadModelError(blocker, { traceId, projection, session: contextSession, turn: contextTurn }));
     }
     attachWorkbenchReadModelDiagnosticOtel(request, { route: "/v1/workbench/traces/:id/events", code: "workbench_trace_not_found", traceId, count: context.count });
+    emitWorkbenchTraceEventsReadOtel(traceId, options, {
+      startTimeMs: startedAt,
+      statusCode: 404,
+      phase: "not_found",
+      pageOptions,
+      readCount: context.count,
+      metadataCount: metadata.count,
+      errorCode: "workbench_trace_not_found"
+    });
     return sendJson(response, 404, workbenchError("workbench_trace_not_found", "Workbench trace is not visible to the current actor.", { traceId }));
   }
   const projection = factProjectionForTrace(metadataFacts, traceId);
   const pageResult = await readModel.queryFacts({ traceId, families: WORKBENCH_TRACE_EVENT_PAGE_FAMILIES, afterProjectedSeq: pageOptions.afterProjectedSeq, limit: pageOptions.limit + 1 });
-  if (pageResult.error) return sendJson(response, 503, workbenchProjectionStoreError(pageResult.error));
+  if (pageResult.error) {
+    emitWorkbenchTraceEventsReadOtel(traceId, options, {
+      startTimeMs: startedAt,
+      statusCode: 503,
+      phase: "events_query_failed",
+      pageOptions,
+      projection,
+      sessionId: factSessionId(session),
+      metadataCount: metadata.count,
+      errorCode: pageResult.error?.code ?? "workbench_trace_events_query_failed"
+    }, pageResult.error);
+    return sendJson(response, 503, workbenchProjectionStoreError(pageResult.error));
+  }
   const traceTurn = factTurnForTrace(metadataFacts, traceId, traceId);
   const turnTraceStatus = normalizeStatus(traceTurn?.status);
   const traceStatus = turnTraceStatus !== "unknown" ? turnTraceStatus : durableTraceStatus(pageResult.facts.traceEvents);
@@ -1761,6 +1854,20 @@ async function handleWorkbenchTraceEventPage(request, response, url, options, ac
   if (missingTraceEvents) {
     const blocker = traceEventsReadModelBlocker("workbench_trace_events_missing", "Workbench trace events are missing from the durable read model.", { traceId, projection, session, route: url.pathname });
     attachWorkbenchReadModelDiagnosticOtel(request, { route: "/v1/workbench/traces/:id/events", code: "workbench_trace_events_missing", sessionId: factSessionId(session), traceId, count: pageResult.count });
+    emitWorkbenchTraceEventsReadOtel(traceId, options, {
+      startTimeMs: startedAt,
+      statusCode: 404,
+      phase: "events_missing",
+      pageOptions,
+      page,
+      projection,
+      sessionId: factSessionId(session),
+      turnId: factTurnId(traceTurn, traceId),
+      readCount: pageResult.count,
+      rawEventCount: factArray(pageResult.facts?.traceEvents).length,
+      metadataCount: metadata.count,
+      errorCode: "workbench_trace_events_missing"
+    });
     return sendJson(response, 404, workbenchTraceEventsReadModelError(blocker, { traceId, projection, session, turn: traceTurn }));
   }
   const responseProjection = page.blocker ? blockedTraceEventProjection(projection, page.blocker) : projection;
@@ -1790,9 +1897,100 @@ async function handleWorkbenchTraceEventPage(request, response, url, options, ac
     secretMaterialStored: false
   };
   recordWorkbenchCacheMetric(options, url, body, startedAt);
+  emitWorkbenchTraceEventsReadOtel(traceId, options, {
+    startTimeMs: startedAt,
+    statusCode: 200,
+    phase: page.blocker ? "blocked" : "succeeded",
+    pageOptions,
+    page,
+    projection: responseProjection,
+    sessionId: body.sessionId,
+    turnId: factTurnId(traceTurn, traceId),
+    readCount: pageResult.count,
+    rawEventCount: factArray(pageResult.facts?.traceEvents).length,
+    metadataCount: metadata.count,
+    traceStatus
+  });
   sendJson(response, 200, body);
 }
 
+function emitWorkbenchTurnStatusReadOtel(traceId, options = {}, fields = {}, error = null) {
+  const safeId = safeTraceId(traceId);
+  if (!safeId) return;
+  const statusCode = Number.isInteger(Number(fields.statusCode)) ? Number(fields.statusCode) : 0;
+  void emitCodeAgentOtelSpan("turn_status_read", safeId, options.env ?? process.env, {
+    startTimeMs: fields.startTimeMs,
+    status: statusCode >= 500 || error ? "error" : "ok",
+    error,
+    attributes: {
+      "http.method": "GET",
+      "http.route": "/v1/workbench/turns/:id",
+      "http.status_code": statusCode || null,
+      phase: fields.phase ?? null,
+      status: fields.status ?? null,
+      terminal: typeof fields.terminal === "boolean" ? fields.terminal : null,
+      sessionId: fields.sessionId ?? null,
+      turnId: fields.turnId ?? safeId,
+      readCount: nonNegativeInteger(fields.readCount),
+      traceEventCount: nonNegativeInteger(fields.traceEventCount),
+      latestProjectedSeq: nonNegativeInteger(fields.latestProjectedSeq),
+      projectionStatus: fields.projectionStatus ?? null,
+      projectionHealth: fields.projectionHealth ?? null,
+      sourceRunId: fields.sourceRunId ?? null,
+      sourceCommandId: fields.sourceCommandId ?? null,
+      errorCode: fields.errorCode ?? null,
+      valuesRedacted: true
+    }
+  });
+}
+
+function emitWorkbenchTraceEventsReadOtel(traceId, options = {}, fields = {}, error = null) {
+  const safeId = safeTraceId(traceId);
+  if (!safeId) return;
+  const page = fields.page ?? {};
+  const range = page.range ?? {};
+  const projection = fields.projection ?? {};
+  const pageOptions = fields.pageOptions ?? {};
+  const statusCode = Number.isInteger(Number(fields.statusCode)) ? Number(fields.statusCode) : 0;
+  const returnedEvents = Array.isArray(page.events) ? page.events.length : nonNegativeInteger(fields.returnedEvents);
+  const afterProjectedSeq = nonNegativeInteger(pageOptions.afterProjectedSeq ?? range.afterProjectedSeq);
+  const limit = nonNegativeInteger(pageOptions.limit ?? range.limit);
+  const hasMore = typeof page.hasMore === "boolean" ? page.hasMore : null;
+  void emitCodeAgentOtelSpan("trace_events_read", safeId, options.env ?? process.env, {
+    startTimeMs: fields.startTimeMs,
+    status: statusCode >= 500 || error ? "error" : "ok",
+    error,
+    attributes: {
+      "http.method": "GET",
+      "http.route": "/v1/workbench/traces/:id/events",
+      "http.status_code": statusCode || null,
+      phase: fields.phase ?? null,
+      sessionId: fields.sessionId ?? null,
+      turnId: fields.turnId ?? safeId,
+      returnedEvents,
+      rawEventCount: nonNegativeInteger(fields.rawEventCount),
+      readCount: nonNegativeInteger(fields.readCount),
+      metadataCount: nonNegativeInteger(fields.metadataCount),
+      sinceSeq: afterProjectedSeq,
+      afterProjectedSeq,
+      limit,
+      fromSeq: nonNegativeInteger(range.fromProjectedSeq),
+      toSeq: nonNegativeInteger(range.toProjectedSeq),
+      totalEvents: nonNegativeInteger(range.total ?? page.eventCount),
+      hasMore,
+      fullTraceLoaded: hasMore === null ? null : !hasMore && !page.blocker,
+      traceLastSeq: nonNegativeInteger(projection.lastProjectedSeq),
+      projectionStatus: projection.projectionStatus ?? null,
+      projectionHealth: projection.projectionHealth ?? null,
+      sourceRunId: projection.sourceRunId ?? null,
+      sourceCommandId: projection.sourceCommandId ?? null,
+      traceStatus: fields.traceStatus ?? page.traceStatus ?? null,
+      errorCode: fields.errorCode ?? null,
+      valuesRedacted: true
+    }
+  });
+}
+
 function traceEventPageFromFacts(sourceEvents, options, metadata = {}) {
   const rows = factArray(sourceEvents).filter((event) => factProjectedSeq(event)).sort(compareFactTraceEventsAsc);
   const collision = projectedSeqCollision(rows);
diff --git a/internal/cloud/workbench-projection-writer.ts b/internal/cloud/workbench-projection-writer.ts
index 020af106..d37038b8 100644
--- a/internal/cloud/workbench-projection-writer.ts
+++ b/internal/cloud/workbench-projection-writer.ts
@@ -112,6 +112,7 @@ export async function writeWorkbenchProjectionEvent({ runtimeStore = null, event
   const sourceSeq = nonNegativeInteger(event.sourceSeq ?? event.seq);
   const sessionId = textValue(event.sessionId ?? requestMeta.sessionId) || null;
   const turnId = textValue(event.turnId) || traceId;
+  const eventType = textValue(event.eventType ?? event.type ?? event.label) || "event";
   const terminal = event.terminal === true || TERMINAL_STATUSES.has(normalizeWorkbenchStatus(event.status));
   const status = terminal ? normalizeWorkbenchStatus(event.status) : "running";
   const checkpointHint = previousCheckpoint && typeof previousCheckpoint === "object" ? previousCheckpoint : null;
@@ -127,7 +128,9 @@ export async function writeWorkbenchProjectionEvent({ runtimeStore = null, event
       "workbench.projection.terminal": false,
       "workbench.projection.suppressed_after_seal": true,
       "workbench.projection.session_id": sessionId,
-      "workbench.projection.turn_id": turnId
+      "workbench.projection.turn_id": turnId,
+      "workbench.projection.source_seq": sourceSeq,
+      "workbench.projection.event_type": eventType
     });
     return { written: false, suppressedAfterSeal: true, valuesPrinted: false };
   }
@@ -161,7 +164,7 @@ export async function writeWorkbenchProjectionEvent({ runtimeStore = null, event
     commandId: textValue(event.commandId) || null,
     sourceSeq,
     sourceEventId,
-    eventType: textValue(event.eventType ?? event.type ?? event.label) || "event",
+    eventType,
     occurredAt,
     updatedAt: projectedAt
   }, {
@@ -224,7 +227,7 @@ export async function writeWorkbenchProjectionEvent({ runtimeStore = null, event
       sourceSeq,
       sourceEventId,
       projectedSeq,
-      eventType: textValue(event.eventType ?? event.type ?? event.label) || "event",
+      eventType,
       terminal,
       sealed: terminal,
       timing: eventTiming,
@@ -280,7 +283,13 @@ export async function writeWorkbenchProjectionEvent({ runtimeStore = null, event
       "workbench.projection.terminal": terminal,
       "workbench.projection.suppressed_after_seal": suppressedAfterSeal,
       "workbench.projection.session_id": sessionId,
-      "workbench.projection.turn_id": turnId
+      "workbench.projection.turn_id": turnId,
+      "workbench.projection.projected_seq": projectedSeq,
+      "workbench.projection.source_seq": sourceSeq,
+      "workbench.projection.source_event_id": sourceEventId,
+      "workbench.projection.event_type": eventType,
+      "workbench.projection.event_id": eventId,
+      "workbench.projection.message_id": messageFact?.messageId ?? null
     });
     return result;
   } catch (error) {
@@ -290,7 +299,13 @@ export async function writeWorkbenchProjectionEvent({ runtimeStore = null, event
       "workbench.projection.terminal": terminal,
       "workbench.projection.suppressed_after_seal": suppressedAfterSeal,
       "workbench.projection.session_id": sessionId,
-      "workbench.projection.turn_id": turnId
+      "workbench.projection.turn_id": turnId,
+      "workbench.projection.projected_seq": projectedSeq,
+      "workbench.projection.source_seq": sourceSeq,
+      "workbench.projection.source_event_id": sourceEventId,
+      "workbench.projection.event_type": eventType,
+      "workbench.projection.event_id": eventId,
+      "workbench.projection.message_id": messageFact?.messageId ?? null
     }, error);
     appendProjectionDiagnostic(defaultCodeAgentTraceStore, traceId, {
       type: "facts",
@@ -351,7 +366,11 @@ async function writeWorkbenchProjectionFacts({ runtimeStore = null, traceStore =
       "workbench.projection.phase": "session-facts",
       "workbench.projection.terminal": facts.turns.some((turn) => turn.terminal === true),
       "workbench.projection.session_id": facts.sessions[0]?.sessionId ?? sessionId ?? null,
-      "workbench.projection.turn_id": facts.turns[0]?.turnId ?? null
+      "workbench.projection.turn_id": facts.turns[0]?.turnId ?? null,
+      "workbench.projection.projected_seq": facts.checkpoints[0]?.projectedSeq ?? facts.turns[0]?.projectedSeq ?? facts.messages[0]?.projectedSeq ?? null,
+      "workbench.projection.source_seq": facts.checkpoints[0]?.sourceSeq ?? facts.turns[0]?.sourceSeq ?? facts.messages[0]?.sourceSeq ?? null,
+      "workbench.projection.source_event_id": facts.checkpoints[0]?.sourceEventId ?? facts.turns[0]?.sourceEventId ?? facts.messages[0]?.sourceEventId ?? null,
+      "workbench.projection.message_id": facts.messages[0]?.messageId ?? null
     });
     return result;
   } catch (error) {
@@ -361,7 +380,11 @@ async function writeWorkbenchProjectionFacts({ runtimeStore = null, traceStore =
       "workbench.projection.phase": "session-facts",
       "workbench.projection.terminal": facts.turns.some((turn) => turn.terminal === true),
       "workbench.projection.session_id": facts.sessions[0]?.sessionId ?? sessionId ?? null,
-      "workbench.projection.turn_id": facts.turns[0]?.turnId ?? null
+      "workbench.projection.turn_id": facts.turns[0]?.turnId ?? null,
+      "workbench.projection.projected_seq": facts.checkpoints[0]?.projectedSeq ?? facts.turns[0]?.projectedSeq ?? facts.messages[0]?.projectedSeq ?? null,
+      "workbench.projection.source_seq": facts.checkpoints[0]?.sourceSeq ?? facts.turns[0]?.sourceSeq ?? facts.messages[0]?.sourceSeq ?? null,
+      "workbench.projection.source_event_id": facts.checkpoints[0]?.sourceEventId ?? facts.turns[0]?.sourceEventId ?? facts.messages[0]?.sourceEventId ?? null,
+      "workbench.projection.message_id": facts.messages[0]?.messageId ?? null
     }, error);
     if (safeId) appendProjectionDiagnostic(traceStore, safeId, {
       type: "facts",