diff --git a/test/helpers/e2e-helpers.ts b/test/helpers/e2e-helpers.ts
index 6b5694f0..b65e0a79 100644
--- a/test/helpers/e2e-helpers.ts
+++ b/test/helpers/e2e-helpers.ts
@@ -30,6 +30,13 @@ export const evalsEnabled = !!process.env.EVALS;
 // Set EVALS_ALL=1 to force all tests. Set EVALS_BASE to override base branch.
 export let selectedTests: string[] | null = null; // null = run all
 
+// EVALS_FAST: skip the 8 slowest tests (all Opus quality tests) for quick feedback
+const FAST_EXCLUDED_TESTS = [
+  'plan-ceo-review-selective', 'plan-ceo-review', 'retro', 'retro-base-branch',
+  'design-consultation-core', 'design-consultation-existing',
+  'qa-fix-loop', 'design-review-fix',
+];
+
 if (evalsEnabled && !process.env.EVALS_ALL) {
   const baseBranch = process.env.EVALS_BASE
     || detectBaseBranch(ROOT)
@@ -48,6 +55,17 @@ if (evalsEnabled && !process.env.EVALS_ALL) {
   // If changedFiles is empty (e.g., on main branch), selectedTests stays null → run all
 }
 
+// Apply EVALS_FAST filter after diff-based selection
+if (evalsEnabled && process.env.EVALS_FAST) {
+  if (selectedTests === null) {
+    // Run all minus excluded
+    selectedTests = Object.keys(E2E_TOUCHFILES).filter(t => !FAST_EXCLUDED_TESTS.includes(t));
+  } else {
+    selectedTests = selectedTests.filter(t => !FAST_EXCLUDED_TESTS.includes(t));
+  }
+  process.stderr.write(`EVALS_FAST: excluded ${FAST_EXCLUDED_TESTS.length} slow tests, running ${selectedTests.length}\n\n`);
+}
+
 export const describeE2E = evalsEnabled ? describe : describe.skip;
 
 /** Wrap a describe block to skip entirely if none of its tests are selected. */
@@ -164,6 +182,9 @@ export function recordE2E(
     exit_reason: result.exitReason,
     timeout_at_turn: result.exitReason === 'timeout' ? result.costEstimate.turnsUsed : undefined,
     last_tool_call: lastTool,
+    model: result.model,
+    first_response_ms: result.firstResponseMs,
+    max_inter_turn_ms: result.maxInterTurnMs,
     ...extra,
   });
 }
diff --git a/test/helpers/eval-store.ts b/test/helpers/eval-store.ts
index 9dd64109..f2f13fce 100644
--- a/test/helpers/eval-store.ts
+++ b/test/helpers/eval-store.ts
@@ -42,6 +42,11 @@ export interface EvalTestEntry {
   timeout_at_turn?: number;   // which turn was active when timeout hit
   last_tool_call?: string;    // e.g. "Write(review-output.md)"
 
+  // Model + timing diagnostics (added for Sonnet/Opus split)
+  model?: string;                // e.g. 'claude-sonnet-4-6' or 'claude-opus-4-6'
+  first_response_ms?: number;    // time from spawn to first NDJSON line
+  max_inter_turn_ms?: number;    // peak latency between consecutive tool calls
+
   // Outcome eval
   detection_rate?: number;
   false_positives?: number;
@@ -65,6 +70,7 @@ export interface EvalResult {
   failed: number;
   total_cost_usd: number;
   total_duration_ms: number;
+  wall_clock_ms?: number;     // wall-clock from collector creation to finalization (shows parallelism)
   tests: EvalTestEntry[];
   _partial?: boolean;  // true for incremental saves, absent in final
 }
@@ -546,6 +552,7 @@ export class EvalCollector {
   private tests: EvalTestEntry[] = [];
   private finalized = false;
   private evalDir: string;
+  private createdAt = Date.now();
 
   constructor(tier: 'e2e' | 'llm-judge', evalDir?: string) {
     this.tier = tier;
@@ -615,6 +622,7 @@ export class EvalCollector {
       failed: this.tests.length - passed,
       total_cost_usd: Math.round(totalCost * 100) / 100,
       total_duration_ms: totalDuration,
+      wall_clock_ms: Date.now() - this.createdAt,
       tests: this.tests,
     };
 
diff --git a/test/helpers/session-runner.ts b/test/helpers/session-runner.ts
index 6654df5f..c9b85de0 100644
--- a/test/helpers/session-runner.ts
+++ b/test/helpers/session-runner.ts
@@ -41,6 +41,12 @@ export interface SkillTestResult {
   output: string;
   costEstimate: CostEstimate;
   transcript: any[];
+  /** Which model was used for this test (added for Sonnet/Opus split diagnostics) */
+  model: string;
+  /** Time from spawn to first NDJSON line, in ms (added for rate-limit diagnostics) */
+  firstResponseMs: number;
+  /** Peak latency between consecutive tool calls, in ms */
+  maxInterTurnMs: number;
 }
 
 const BROWSE_ERROR_PATTERNS = [
@@ -116,6 +122,8 @@ export async function runSkillTest(options: {
   timeout?: number;
   testName?: string;
   runId?: string;
+  /** Model to use. Defaults to claude-sonnet-4-6 (overridable via EVALS_MODEL env). */
+  model?: string;
 }): Promise<SkillTestResult> {
   const {
     prompt,
@@ -126,6 +134,7 @@ export async function runSkillTest(options: {
     testName,
     runId,
   } = options;
+  const model = options.model ?? process.env.EVALS_MODEL ?? 'claude-sonnet-4-6';
 
   const startTime = Date.now();
   const startedAt = new Date().toISOString();
@@ -144,6 +153,7 @@ export async function runSkillTest(options: {
   // avoid shell escaping issues. --verbose is required for stream-json mode.
   const args = [
     '-p',
+    '--model', model,
     '--output-format', 'stream-json',
     '--verbose',
     '--dangerously-skip-permissions',
@@ -175,6 +185,9 @@ export async function runSkillTest(options: {
   const collectedLines: string[] = [];
   let liveTurnCount = 0;
   let liveToolCount = 0;
+  let firstResponseMs = 0;
+  let lastToolTime = 0;
+  let maxInterTurnMs = 0;
   const stderrPromise = new Response(proc.stderr).text();
 
   const reader = proc.stdout.getReader();
@@ -201,7 +214,15 @@ export async function runSkillTest(options: {
             for (const item of content) {
               if (item.type === 'tool_use') {
                 liveToolCount++;
-                const elapsed = Math.round((Date.now() - startTime) / 1000);
+                const now = Date.now();
+                const elapsed = Math.round((now - startTime) / 1000);
+                // Track timing telemetry
+                if (firstResponseMs === 0) firstResponseMs = now - startTime;
+                if (lastToolTime > 0) {
+                  const interTurn = now - lastToolTime;
+                  if (interTurn > maxInterTurnMs) maxInterTurnMs = interTurn;
+                }
+                lastToolTime = now;
                 const progressLine = `  [${elapsed}s] turn ${liveTurnCount} tool #${liveToolCount}: ${item.name}(${truncate(JSON.stringify(item.input || {}), 80)})\n`;
                 process.stderr.write(progressLine);
 
@@ -330,5 +351,5 @@ export async function runSkillTest(options: {
     turnsUsed,
   };
 
-  return { toolCalls, browseErrors, exitReason, duration, output: resultLine?.result || '', costEstimate, transcript };
+  return { toolCalls, browseErrors, exitReason, duration, output: resultLine?.result || '', costEstimate, transcript, model, firstResponseMs, maxInterTurnMs };
 }