V48 Gate 3 (implementation-only): Hover last call chain on failed pipeline rows

Show error plus last phase→agent→step→failsafe→generation lines when hovering
FAILED/CANCELLED/interrupted status pills. History supports ?tail=N for a
lightweight event window used by the preview.

Author: geraldarthurdavis

packages/api/src/routes/executions.ts

@@ -631,7 +631,7 @@ export async function postExecutionHistoryRoute(request: Request) {
 }
 
 export async function getExecutionHistoryRunRoute(
-  _request: Request,
+  request: Request,
   params: { runId?: string | null | undefined },
 ) {
   const userId = await requireExecutionRouteUserId();
@@ -644,6 +644,19 @@ export async function getExecutionHistoryRunRoute(
     return createJsonResponse({ error: 'Missing runId parameter' }, 400);
   }
 
+  // `?tail=N` — last N events only (for failure hover previews). Full history
+  // when omitted (paginated past the PostgREST 1000-row default).
+  let tail: number | null = null;
+  try {
+    const raw = new URL(request.url).searchParams.get('tail');
+    if (raw) {
+      const n = Number.parseInt(raw, 10);
+      if (Number.isFinite(n) && n > 0) tail = Math.min(n, 50);
+    }
+  } catch {
+    tail = null;
+  }
+
   const { data: run, error: runError } = await supabaseAdmin
     .from('executions')
     .select(
@@ -663,21 +676,18 @@ export async function getExecutionHistoryRunRoute(
     return createJsonResponse({ error: 'Execution not found or access denied' }, 404);
   }
 
-  // PostgREST/Supabase defaults to max 1000 rows. Deposit synthesis runs produce
-  // multi-thousand event streams (QA: refresh dropped the second half of a
-  // ~30m run and halved the clock because only the first 1000 events loaded).
-  // Page through the full event history in order.
-  const EVENT_PAGE_SIZE = 1000;
   const events: ExecutionEventRow[] = [];
-  let eventOffset = 0;
-  for (;;) {
+  let eventsTruncated = false;
+
+  if (tail !== null) {
+    // Newest-first page, then reverse so clients get chronological order.
     const { data: page, error: eventsError } = await supabaseAdmin
       .from('execution_events')
       .select('id, run_id, event_type, event_data, created_at, agent_name, phase')
       .eq('run_id', runId)
-      .order('created_at', { ascending: true })
-      .order('id', { ascending: true })
-      .range(eventOffset, eventOffset + EVENT_PAGE_SIZE - 1);
+      .order('created_at', { ascending: false })
+      .order('id', { ascending: false })
+      .range(0, tail - 1);
 
     if (eventsError) {
       return createJsonResponse(
@@ -686,25 +696,56 @@ export async function getExecutionHistoryRunRoute(
       );
     }
     const batch = Array.isArray(page) ? (page as ExecutionEventRow[]) : [];
-    events.push(...batch);
-    if (batch.length < EVENT_PAGE_SIZE) break;
-    eventOffset += EVENT_PAGE_SIZE;
-    // Hard ceiling so a runaway table cannot unbounded-read the API process.
-    if (eventOffset >= 50_000) break;
+    events.push(...batch.reverse());
+  } else {
+    // PostgREST/Supabase defaults to max 1000 rows. Deposit synthesis runs produce
+    // multi-thousand event streams (QA: refresh dropped the second half of a
+    // ~30m run and halved the clock because only the first 1000 events loaded).
+    // Page through the full event history in order.
+    const EVENT_PAGE_SIZE = 1000;
+    let eventOffset = 0;
+    for (;;) {
+      const { data: page, error: eventsError } = await supabaseAdmin
+        .from('execution_events')
+        .select('id, run_id, event_type, event_data, created_at, agent_name, phase')
+        .eq('run_id', runId)
+        .order('created_at', { ascending: true })
+        .order('id', { ascending: true })
+        .range(eventOffset, eventOffset + EVENT_PAGE_SIZE - 1);
+
+      if (eventsError) {
+        return createJsonResponse(
+          { error: toErrorMessage(eventsError, 'Failed to fetch execution event history') },
+          500,
+        );
+      }
+      const batch = Array.isArray(page) ? (page as ExecutionEventRow[]) : [];
+      events.push(...batch);
+      if (batch.length < EVENT_PAGE_SIZE) break;
+      eventOffset += EVENT_PAGE_SIZE;
+      // Hard ceiling so a runaway table cannot unbounded-read the API process.
+      if (eventOffset >= 50_000) {
+        eventsTruncated = true;
+        break;
+      }
+    }
   }
 
   const normalizedRun = normalizeExecutionHistoryRow(run);
-  const terminalJournal = await fetchTerminalJournalReadback(run.id, normalizedRun);
+  // Skip heavy journal join for lightweight tail previews (table hover).
+  const terminalJournal =
+    tail !== null ? null : await fetchTerminalJournalReadback(run.id, normalizedRun);
 
   return createJsonResponse({
     run: {
       ...normalizedRun,
-      terminal_journal: terminalJournal,
+      ...(terminalJournal ? { terminal_journal: terminalJournal } : {}),
     },
     events: events.map(normalizeExecutionEventRow),
     eventCount: events.length,
-    eventsTruncated: eventOffset >= 50_000,
-    terminal_journal: terminalJournal,
+    eventsTruncated,
+    tail,
+    ...(terminalJournal ? { terminal_journal: terminalJournal } : {}),
   });
 }
 

uapi/app/terminal/terminal-transactions.ts

@@ -26,6 +26,8 @@ export interface TerminalTransactionRecord {
   isOwnTransaction: boolean;
   transactionLens: Exclude<TerminalTransactionLens, 'all'>;
   searchableText: string;
+  /** Source-safe failure text for failed/cancelled hover previews. */
+  errorMessage?: string | null;
 }
 
 export interface TerminalTransactionFilters {
@@ -65,6 +67,11 @@ export function normalizeTerminalTransactions(runs: WorkspaceRun[]): TerminalTra
     const summary =
       normalizeWhitespace(run.summary) || 'Inspect this Bitcode execution from the central Bitcode Terminal detail surface.';
     const status = normalizeStatus(run.status);
+    const errorMessage =
+      normalizeWhitespace(run.errorMessage) ||
+      (status === 'failed' || status === 'cancelled' || status === 'interrupted'
+        ? normalizeWhitespace(run.summary)
+        : null);
     const proofStatus = normalizeWhitespace(run.proofStatus) || agenticExecution.proofStatus;
     const closureFocus = normalizeWhitespace(run.closureFocus) || agenticExecution.closureFocus;
     const transactionLens = run.transactionLens || agenticExecution.lens;
@@ -76,6 +83,7 @@ export function normalizeTerminalTransactions(runs: WorkspaceRun[]): TerminalTra
       type,
       typeLabel,
       status,
+      errorMessage,
       repository,
       branch,
       participant,
@@ -105,6 +113,7 @@ export function normalizeTerminalTransactions(runs: WorkspaceRun[]): TerminalTra
       isOwnTransaction: Boolean(run.isOwnTransaction),
       transactionLens,
       searchableText,
+      errorMessage,
     };
   });
 }

uapi/components/base/bitcode/execution/BitcodeTransactionsDataTable.tsx

@@ -7,6 +7,7 @@ import { formatAgenticExecutionLabel } from '@bitcode/api/src/executions/agentic
 import BitcodeInlineExplainer from './BitcodeInlineExplainer';
 import { BITCODE_TRANSACTION_COLUMN_EXPLAINERS } from './bitcode-transaction-explainers';
 import type { TransactionRecord } from './bitcode-transaction-types';
+import { TransactionStatusHoverBadge } from './TransactionStatusHoverBadge';
 
 function formatTimestamp(value: string) {
   try {
@@ -26,12 +27,6 @@ function formatTypeLabel(value: string, label?: string) {
   return label || formatAgenticExecutionLabel(value);
 }
 
-function statusTone(status: string) {
-  if (status === 'completed') return 'border-emerald-500/30 bg-emerald-500/10 text-emerald-200';
-  if (status === 'error' || status === 'failed') return 'border-red-500/30 bg-red-500/10 text-red-200';
-  return 'border-amber-500/30 bg-amber-500/10 text-amber-100';
-}
-
 interface BitcodeTransactionsDataTableProps {
   records: TransactionRecord[];
   selectedTransactionId: string | null;
@@ -142,11 +137,12 @@ export default function BitcodeTransactionsDataTable({
                       </span>
                     </td>
                     <td className="px-3 py-3 align-top">
-                      <span
-                        className={` border px-2.5 py-1 text-[0.68rem] uppercase tracking-[0.18em] ${statusTone(record.status)}`}
-                      >
-                        {record.status}
-                      </span>
+                      <TransactionStatusHoverBadge
+                        runId={record.id}
+                        status={record.status}
+                        errorMessage={record.errorMessage}
+                        summary={record.summary}
+                      />
                     </td>
                     <td className="px-3 py-3 align-top text-sm text-neutral-200">
                       <p>{record.participant}</p>