diff --git a/.oxlintrc.json b/.oxlintrc.json
index 3e0b31f..a639dd3 100644
--- a/.oxlintrc.json
+++ b/.oxlintrc.json
@@ -8,7 +8,11 @@
     }
   },
   "rules": {
+    "complexity": ["error", { "max": 10 }],
     "import/no-cycle": "error",
+    "max-depth": ["error", { "max": 2 }],
+    "max-lines": ["error", { "max": 500 }],
+    "max-params": ["error", { "max": 3 }],
     "typescript/await-thenable": "error",
     "typescript/no-floating-promises": "error",
     "typescript/no-misused-promises": "error"
diff --git a/src/data/article.ts b/src/data/article.ts
index 7653dbd..98e9b5e 100644
--- a/src/data/article.ts
+++ b/src/data/article.ts
@@ -137,27 +137,27 @@ function transformOutsideFences(markdown: string, transform: (prose: string) =>
   return restoreFencedBlocks(transform(protectedMarkdown), fencedBlocks);
 }
 
+type Fence = { character: string; length: number; lines: string[] };
+
 function protectFencedBlocks(markdown: string, fencedBlocks: string[]): string {
   const lines = markdown.split("\n");
   const protectedLines: string[] = [];
-  let fence: { character: string; length: number; lines: string[] } | undefined;
+  let fence: Fence | undefined;
 
   for (const line of lines) {
-    const marker = /^(?:\s*)(`{3,}|~{3,})/u.exec(line)?.[1];
-    if (fence === undefined && marker !== undefined) {
+    const marker = fence === undefined ? /^(?:\s*)(`{3,}|~{3,})/u.exec(line)?.[1] : undefined;
+    if (marker !== undefined) {
       fence = { character: marker[0], length: marker.length, lines: [line] };
       continue;
     }
-    if (fence !== undefined) {
-      fence.lines.push(line);
-      const closing = /^ {0,3}(`{3,}|~{3,})[ \t]*\r?$/u.exec(line)?.[1];
-      if (closing?.[0] === fence.character && closing.length >= fence.length) {
-        protectedLines.push(storeFencedBlock(fence.lines, fencedBlocks));
-        fence = undefined;
-      }
+    if (fence === undefined) {
+      protectedLines.push(line);
       continue;
     }
-    protectedLines.push(line);
+    fence.lines.push(line);
+    if (!closesFence(line, fence)) continue;
+    protectedLines.push(storeFencedBlock(fence.lines, fencedBlocks));
+    fence = undefined;
   }
 
   if (fence !== undefined) {
@@ -166,6 +166,11 @@ function protectFencedBlocks(markdown: string, fencedBlocks: string[]): string {
   return protectedLines.join("\n");
 }
 
+function closesFence(line: string, fence: Fence): boolean {
+  const closing = /^ {0,3}(`{3,}|~{3,})[ \t]*\r?$/u.exec(line)?.[1];
+  return closing?.[0] === fence.character && closing.length >= fence.length;
+}
+
 function storeFencedBlock(lines: string[], fencedBlocks: string[]): string {
   const index = fencedBlocks.push(lines.join("\n")) - 1;
   return `@@FUREDEA_FENCED_BLOCK_${index}@@`;
@@ -180,7 +185,8 @@ function restoreFencedBlocks(markdown: string, fencedBlocks: string[]): string {
 function convertCaptions(markdown: string): string {
   return markdown.replace(
     /^!\[([^\]]*)\]\(([^)\s]+)\)\n([_*])(.+)\3$/gmu,
-    (_match, alt: string, url: string, _delimiter: string, caption: string) => {
+    (_match, ...captures: string[]) => {
+      const [alt, url, , caption] = captures;
       return [
         "<figure>",
         `<img src="${escapeHtml(url)}" alt="${escapeHtml(alt)}">`,
diff --git a/src/integrations/esa.test.ts b/src/integrations/esa.test.ts
index 48cea43..101621a 100644
--- a/src/integrations/esa.test.ts
+++ b/src/integrations/esa.test.ts
@@ -215,6 +215,40 @@ test.each([0, -1, 1, 1.5, "2"])(
   },
 );
 
+test.each([
+  ["name", 1],
+  ["body_md", null],
+  ["tags", [1]],
+  ["category", 1],
+  ["wip", "false"],
+])("refuses to publish when a searched post has an invalid %s", async (field, value) => {
+  const methods: string[] = [];
+  const fetcher: typeof fetch = async (input, options) => {
+    methods.push(new Request(input, options).method);
+    return Response.json({
+      posts: [
+        {
+          number: 42,
+          url: "https://example-team.esa.io/posts/42",
+          ...PAYLOAD.post,
+          [field]: value,
+        },
+      ],
+    });
+  };
+
+  await expect(
+    upsertEsaPost({
+      team: "example-team",
+      accessToken: ACCESS_TOKEN,
+      canonicalUrl: "https://furedea.com/ja/blog/article-publishing/",
+      payload: PAYLOAD,
+      fetcher,
+    }),
+  ).rejects.toThrow("esa API returned an invalid post search response.");
+  expect(methods.filter((method) => method !== "GET")).toEqual([]);
+});
+
 test("does not publish when a later search page fails", async () => {
   const methods: string[] = [];
   const fetcher: typeof fetch = async (input, options) => {
diff --git a/src/integrations/esa.ts b/src/integrations/esa.ts
index 9eda65b..9efa31f 100644
--- a/src/integrations/esa.ts
+++ b/src/integrations/esa.ts
@@ -173,12 +173,20 @@ function isEsaPostSearchResult(value: unknown): value is EsaPostSearchResult {
 }
 
 function isEsaPostSummary(value: unknown): value is EsaPostSummary {
+  return isEsaPostResult(value) && hasEsaPostContent(value) && hasEsaPostMetadata(value);
+}
+
+function hasEsaPostContent(value: object): boolean {
   return (
-    isEsaPostResult(value) &&
     "name" in value &&
     typeof value.name === "string" &&
     "body_md" in value &&
-    typeof value.body_md === "string" &&
+    typeof value.body_md === "string"
+  );
+}
+
+function hasEsaPostMetadata(value: object): boolean {
+  return (
     "tags" in value &&
     Array.isArray(value.tags) &&
     value.tags.every((tag) => typeof tag === "string") &&
diff --git a/tests/performance/performance_report.ts b/tests/performance/performance_report.ts
index 706036f..e881a09 100644
--- a/tests/performance/performance_report.ts
+++ b/tests/performance/performance_report.ts
@@ -68,8 +68,7 @@ function renderRow(entry: PerformanceReportEntry): string {
       (value) => value.toFixed(3),
     ),
     unitWithRange(
-      metrics.blockingTime,
-      samples.map(({ blockingTime }) => blockingTime),
+      { median: metrics.blockingTime, samples: samples.map(({ blockingTime }) => blockingTime) },
       "ms",
       Math.round,
     ),
@@ -89,12 +88,11 @@ function seconds(milliseconds: number): string {
 }
 
 function secondsWithRange(median: number, samples: number[]): string {
-  return unitWithRange(median, samples, "s", seconds);
+  return unitWithRange({ median, samples }, "s", seconds);
 }
 
 function unitWithRange(
-  median: number,
-  samples: number[],
+  { median, samples }: { median: number; samples: number[] },
   unit: string,
   format: (value: number) => string | number,
 ): string {