test(server): wire budget measures what clients fetch today, and the PR comment shows every row

.github/scripts/thread-transfer-report.cjs

@@ -3,6 +3,7 @@ const path = require("node:path");
 
 const ARTIFACT_NAME = "thread-transfer-results";
 const RESULT_FILE = "thread-transfer-result.json";
+const SCENARIOS_FILE = "thread-transfer-scenarios.json";
 const COMMENT_MARKER = "<!-- t3-thread-transfer-report -->";
 const PROVIDERS = ["codex", "claudeAgent"];
 const OBSERVED_KEYS = [
@@ -29,6 +30,12 @@ const SCENARIO_KEYS = [
   "measuredMcpResultBytes",
 ];
 
+const SCENARIO_ROW_KEYS = ["phase", "metric", "unit", "observed", "ceiling"];
+// These labels come from the PR and reach a comment the bot posts: no markup, links or mentions.
+// GitHub still links plain text such as `GH-26`, so they are rendered as code spans.
+const SCENARIO_LABEL = /^[A-Za-z0-9][A-Za-z0-9 ,-]{0,79}$/;
+const MAX_SCENARIO_ROWS = 100;
+
 function resultShaMarker(sha) {
   return `<!-- t3-thread-transfer-result-sha:${sha} -->`;
 }
@@ -85,15 +92,63 @@ function validateResult(value) {
   return value;
 }
 
-function readResult(directory) {
+function validateScenarios(value) {
+  assertExactKeys(value, ["schemaVersion", "providers"], "scenarios");
+  if (value.schemaVersion !== 1) {
+    throw new Error("scenarios.schemaVersion must be 1");
+  }
+  assertExactKeys(value.providers, PROVIDERS, "scenarios.providers");
+  for (const provider of PROVIDERS) {
+    const rows = value.providers[provider];
+    if (!Array.isArray(rows) || rows.length > MAX_SCENARIO_ROWS) {
+      throw new Error(
+        `scenarios.providers.${provider} must list at most ${MAX_SCENARIO_ROWS} rows`,
+      );
+    }
+    const seen = new Set();
+    for (const [index, row] of rows.entries()) {
+      const label = `scenarios.providers.${provider}[${index}]`;
+      assertExactKeys(row, SCENARIO_ROW_KEYS, label);
+      for (const key of ["phase", "metric"]) {
+        if (typeof row[key] !== "string" || !SCENARIO_LABEL.test(row[key])) {
+          throw new Error(`${label}.${key} must be a short plain label`);
+        }
+      }
+      if (row.unit !== "bytes" && row.unit !== "count") {
+        throw new Error(`${label}.unit must be bytes or count`);
+      }
+      assertMetric(row.observed, `${label}.observed`);
+      assertMetric(row.ceiling, `${label}.ceiling`);
+      const key = scenarioKey(row);
+      if (seen.has(key)) throw new Error(`${label} repeats an earlier row`);
+      seen.add(key);
+    }
+  }
+  return value;
+}
+
+function scenarioKey(row) {
+  return `${row.phase}|${row.metric}`;
+}
+
+function readArtifactFile(directory, name, validate) {
   if (!directory) return undefined;
-  const file = path.join(directory, RESULT_FILE);
+  const file = path.join(directory, name);
   if (!fs.existsSync(file)) return undefined;
   const stat = fs.lstatSync(file);
   if (!stat.isFile() || stat.size > 64 * 1_024) {
-    throw new Error("thread transfer result must be a regular file smaller than 64 KiB");
+    throw new Error(`${name} must be a regular file smaller than 64 KiB`);
   }
-  return validateResult(JSON.parse(fs.readFileSync(file, "utf8")));
+  return validate(JSON.parse(fs.readFileSync(file, "utf8")));
+}
+
+function readResult(directory) {
+  return readArtifactFile(directory, RESULT_FILE, validateResult);
+}
+
+// Older runs upload only the result file, so a run without scenarios is still a valid run.
+function readScenarios(directory) {
+  return readArtifactFile(directory, SCENARIOS_FILE, validateScenarios);
 }
 
 function formatBytes(bytes) {
@@ -103,7 +158,7 @@ function formatBytes(bytes) {
 }
 
 function formatValue(value, kind) {
-  return kind === "messages" ? value.toLocaleString("en-US") : formatBytes(value);
+  return kind === "bytes" ? formatBytes(value) : value.toLocaleString("en-US");
 }
 
 function formatImpact(current, baseline, kind) {
@@ -136,6 +191,77 @@ const METRICS = [
   { key: "measuredTurnWebSocketMessages", label: "Live turn messages", kind: "messages" },
 ];
 
+function providerLabel(provider) {
+  return provider === "codex" ? "Codex" : "Claude";
+}
+
+/**
+ * The scenario rows of a run against the same rows on `main`. Rows that fail or differ from
+ * `main` are listed in the open; the full table is collapsed below them.
+ */
+function renderScenarios(current, baseline, ceilingChanges) {
+  if (!current) return { lines: [], failed: false };
+  const header = [
+    "| Provider | Scenario | Metric | Main baseline | This PR | Impact | PR ceiling | |",
+    "| --- | --- | --- | ---: | ---: | ---: | ---: | --- |",
+  ];
+  const all = [];
+  const notable = [];
+  let failed = false;
+  let withoutBaseline = 0;
+
+  for (const provider of PROVIDERS) {
+    const baselineRows = new Map(
+      (baseline?.providers[provider] ?? []).map((row) => [scenarioKey(row), row]),
+    );
+    for (const row of current.providers[provider]) {
+      const before = baselineRows.get(scenarioKey(row));
+      const beforeObserved = before?.unit === row.unit ? before.observed : undefined;
+      const pass = row.observed <= row.ceiling;
+      failed ||= !pass;
+      if (beforeObserved === undefined) withoutBaseline += 1;
+      const line = `| ${providerLabel(provider)} | \`${row.phase}\` | \`${row.metric}\` | ${beforeObserved === undefined ? "—" : formatValue(beforeObserved, row.unit)} | ${formatValue(row.observed, row.unit)} | ${formatImpact(row.observed, beforeObserved, row.unit)} | ${formatValue(row.ceiling, row.unit)} | ${pass ? "✅" : "❌"} |`;
+      all.push(line);
+      if (!pass || (beforeObserved !== undefined && beforeObserved !== row.observed)) {
+        notable.push(line);
+      }
+      if (beforeObserved !== undefined && before.ceiling !== row.ceiling) {
+        ceilingChanges.push(
+          `- ${providerLabel(provider)} \`${row.phase}\` \`${row.metric}\`: ${formatValue(before.ceiling, row.unit)} → ${formatValue(row.ceiling, row.unit)}`,
+        );
+      }
+    }
+  }
+
+  const compared = all.length - withoutBaseline;
+  const summary = !baseline
+    ? `No \`main\` baseline exists yet for these ${all.length} scenario measurements.`
+    : [
+        notable.length > 0
+          ? `${notable.length} of ${all.length} scenario measurements changed or failed.`
+          : `${compared === all.length ? "All " : ""}${compared} scenario measurements match \`main\`.`,
+        ...(withoutBaseline > 0 ? [`${withoutBaseline} have no \`main\` baseline.`] : []),
+      ].join(" ");
+  return {
+    failed,
+    lines: [
+      "### Other scenarios",
+      "",
+      summary,
+      ...(notable.length > 0 ? ["", ...header, ...notable] : []),
+      "",
+      "<details>",
+      `<summary>All ${all.length} scenario measurements</summary>`,
+      "",
+      ...header,
+      ...all,
+      "",
+      "</details>",
+      "",
+    ],
+  };
+}
+
 function renderComment(input) {
   const current = input.current;
   const baseline = input.baseline;
@@ -154,16 +280,22 @@ function renderComment(input) {
       const pass = observed <= ceiling;
       failed ||= !pass;
       rows.push(
-        `| ${provider === "codex" ? "Codex" : "Claude"} | ${metric.label} | ${baselineObserved === undefined ? "—" : formatValue(baselineObserved, metric.kind)} | ${formatValue(observed, metric.kind)} | ${formatImpact(observed, baselineObserved, metric.kind)} | ${formatValue(ceiling, metric.kind)} | ${pass ? "✅" : "❌"} |`,
+        `| ${providerLabel(provider)} | ${metric.label} | ${baselineObserved === undefined ? "—" : formatValue(baselineObserved, metric.kind)} | ${formatValue(observed, metric.kind)} | ${formatImpact(observed, baselineObserved, metric.kind)} | ${formatValue(ceiling, metric.kind)} | ${pass ? "✅" : "❌"} |`,
       );
 
       if (comparable && baseline.providers[provider].ceiling[metric.key] !== ceiling) {
         ceilingChanges.push(
-          `- ${provider === "codex" ? "Codex" : "Claude"} ${metric.label}: ${formatValue(baseline.providers[provider].ceiling[metric.key], metric.kind)} → ${formatValue(ceiling, metric.kind)}`,
+          `- ${providerLabel(provider)} ${metric.label}: ${formatValue(baseline.providers[provider].ceiling[metric.key], metric.kind)} → ${formatValue(ceiling, metric.kind)}`,
         );
       }
     }
   }
+  const scenarios = renderScenarios(
+    input.currentScenarios,
+    input.baselineScenarios,
+    ceilingChanges,
+  );
+  failed ||= scenarios.failed;
 
   const baselineLink = input.baselineRun
     ? `[\`${input.baselineRun.sha.slice(0, 7)}\`](${input.baselineRun.url})`
@@ -203,6 +335,7 @@ function renderComment(input) {
     "| --- | --- | ---: | ---: | ---: | ---: | --- |",
     ...rows,
     "",
+    ...scenarios.lines,
     `Baseline: ${baselineLink} · PR result: ${currentLink} · Source CI: ${input.currentRun.conclusion}`,
     "",
     "<details>",
@@ -212,7 +345,7 @@ function renderComment(input) {
     "",
     ...PROVIDERS.map(
       (provider) =>
-        `- ${provider === "codex" ? "Codex" : "Claude"} decoded thread snapshot: ${formatBytes(current.providers[provider].observed.threadSnapshotDecodedBytes)}`,
+        `- ${providerLabel(provider)} decoded thread snapshot: ${formatBytes(current.providers[provider].observed.threadSnapshotDecodedBytes)}`,
     ),
     "",
     "</details>",
@@ -437,7 +570,14 @@ async function publish({ github, context, core }) {
         url: `https://github.com/${context.repo.owner}/${context.repo.repo}/actions/runs/${process.env.BASELINE_RUN_ID}`,
       }
     : undefined;
-  const body = renderComment({ current, baseline, currentRun, baselineRun });
+  const body = renderComment({
+    current,
+    baseline,
+    currentScenarios: readScenarios(process.env.PR_RESULT_DIR),
+    baselineScenarios: readScenarios(process.env.BASELINE_RESULT_DIR),
+    currentRun,
+    baselineRun,
+  });
   const published = await upsertCommentForCurrentHead(
     github,
     context,
@@ -458,4 +598,5 @@ module.exports = {
   resolve,
   upsertCommentForCurrentHead,
   validateResult,
+  validateScenarios,
 };

.github/scripts/thread-transfer-report.test.cjs

@@ -2,9 +2,11 @@ const assert = require("node:assert/strict");
 const test = require("node:test");
 
 const {
+  renderComment,
   resolve,
   upsertCommentForCurrentHead,
   validateResult,
+  validateScenarios,
 } = require("./thread-transfer-report.cjs");
 
 function result(overrides = {}) {
@@ -40,6 +42,29 @@ function result(overrides = {}) {
   };
 }
 
+function scenarios(overrides = {}) {
+  const rows = [
+    {
+      phase: "long turn finished, cold open",
+      metric: "HTTP decoded",
+      unit: "bytes",
+      observed: 390_000,
+      ceiling: 420_000,
+    },
+    {
+      phase: "idle thread resume",
+      metric: "WebSocket messages",
+      unit: "count",
+      observed: 1,
+      ceiling: 1,
+    },
+  ];
+  return {
+    schemaVersion: 1,
+    providers: { codex: [{ ...rows[0], ...overrides }, rows[1]], claudeAgent: rows },
+  };
+}
+
 test("validates the fixed artifact schema", () => {
   assert.equal(validateResult(result()).schemaVersion, 1);
   assert.throws(
@@ -50,6 +75,60 @@ test("validates the fixed artifact schema", () => {
     () => validateResult(result({ totalWireBytes: "lots" })),
     /non-negative safe integer/,
   );
+
+  assert.equal(validateScenarios(scenarios()).schemaVersion, 1);
+  for (const phase of ["@everyone", "[link](https://example.com)", "a | b", "<img>", ""]) {
+    assert.throws(() => validateScenarios(scenarios({ phase })), /short plain label/);
+  }
+  assert.throws(() => validateScenarios(scenarios({ note: "extra" })), /unexpected fields/);
+  assert.throws(() => validateScenarios(scenarios({ ceiling: null })), /non-negative safe integer/);
+  assert.throws(
+    () =>
+      validateScenarios(scenarios({ phase: "idle thread resume", metric: "WebSocket messages" })),
+    /repeats an earlier row/,
+  );
+});
+
+test("lists scenario rows that changed or failed above the collapsed table", () => {
+  const run = { sha: "abcdef1234", url: "https://example.com/run", conclusion: "success" };
+  const render = (currentScenarios, baselineScenarios) =>
+    renderComment({
+      current: result(),
+      baseline: result(),
+      currentScenarios,
+      baselineScenarios,
+      currentRun: run,
+      baselineRun: { ...run, matchesBase: true },
+    });
+  const open = (body) => body.slice(0, body.indexOf("<details>"));
+
+  const unchanged = render(scenarios(), scenarios());
+  assert.match(unchanged, /✅ Thread transfer remains within every enforced ceiling/);
+  assert.match(open(unchanged), /All 4 scenario measurements match `main`/);
+  assert.doesNotMatch(open(unchanged), /long turn finished, cold open/);
+
+  const grown = render(scenarios({ observed: 400_000 }), scenarios());
+  assert.match(open(grown), /1 of 4 scenario measurements changed or failed/);
+  assert.match(
+    open(grown),
+    /\| Codex \| `long turn finished, cold open` \| `HTTP decoded` \| 380\.9 KiB \| 390\.6 KiB \| \+9\.8 KiB \(\+2\.6%\) \| 410\.2 KiB \| ✅ \|/,
+  );
+
+  const over = render(scenarios({ observed: 430_000, ceiling: 425_000 }), scenarios());
+  assert.match(over, /❌ One or more thread transfer ceilings were exceeded/);
+  assert.match(
+    over,
+    /Codex `long turn finished, cold open` `HTTP decoded`: 410\.2 KiB → 415\.0 KiB/,
+  );
+
+  // A row `main` does not have is not reported as matching it.
+  const added = render(scenarios({ phase: "GH-26" }), scenarios());
+  assert.match(open(added), /3 scenario measurements match `main`\. 1 have no `main` baseline\./);
+  assert.match(added, /\| Codex \| `GH-26` \|/);
+
+  // A main run from before the scenario file has nothing to compare; a PR run from before it has no section.
+  assert.match(open(render(scenarios(), undefined)), /No `main` baseline exists yet/);
+  assert.doesNotMatch(render(undefined, scenarios()), /Other scenarios/);
 });
 
 test("resolves a fallback PR with a redacted head repo and exact main baseline", async () => {

.github/workflows/ci.yml

@@ -503,6 +503,7 @@ jobs:
         env:
           T3CODE_TRANSFER_BUDGET_REPORT_PATH: ${{ runner.temp }}/t3code-transfer-budget.md
           T3CODE_TRANSFER_BUDGET_RESULT_PATH: ${{ runner.temp }}/thread-transfer-result.json
+          T3CODE_TRANSFER_BUDGET_SCENARIOS_PATH: ${{ runner.temp }}/thread-transfer-scenarios.json
         run: >-
           vp run test:cached -- --shard ${{ matrix.shard }}/${{ strategy.job-total }}
           --uncached apps/server/integration/transferBudgetV2.integration.test.ts
@@ -543,7 +544,9 @@ jobs:
         uses: actions/upload-artifact@v7
         with:
           name: thread-transfer-results
-          path: ${{ runner.temp }}/thread-transfer-result.json
+          path: |
+            ${{ runner.temp }}/thread-transfer-result.json
+            ${{ runner.temp }}/thread-transfer-scenarios.json
           if-no-files-found: ignore
           retention-days: 30