feat: support multiple blog categories

blogs/AGENTS.md

@@ -14,11 +14,13 @@ title: "Tuning Reth for payments: how we hit 21,200 TPS"
 excerpt: "One or two sentences shown on the index and as the post's lede."
 date: 2026-06-02
 category: technical # network-upgrades | events | technical | case-studies
+# Use an inline list when a post belongs to multiple categories:
+# category: [technical, case-studies]
 featured: true # optional — pins the post to the hero card on /blog
 ---
 ```
 
-`category` must be one of the four slugs above (the build fails loudly otherwise). At most one post should be `featured`; if none is, the newest post takes the hero card.
+`category` must be one of the four slugs above or an inline list of those slugs (the build fails loudly otherwise). At most one post should be `featured`; if none is, the newest post takes the hero card.
 
 ## Body
 

blogs/human-authorization-in-agentic-workflows.md

@@ -2,7 +2,7 @@
 title: "Human Authorization in Agentic Workflows"
 excerpt: "How Tempo enables AI-accelerated development securely"
 date: 2026-08-17
-category: case-studies
+category: [technical, case-studies]
 ---
 
 At Tempo, we are building more workflows where software can move quickly on a person's behalf. That is useful, but it can also be risky.

src/marketing/app/blog/[slug]/page.tsx

@@ -48,9 +48,14 @@ export default function BlogPostPage({ params }: { params: { slug: string } }) {
             </Link>
 
             <div className="mt-8 flex flex-wrap items-center gap-3">
-              <span className="whitespace-nowrap border border-line-strong px-2.5 py-[3px] font-mono text-[11px] text-foreground/50 uppercase tracking-[0.02em]">
-                {categoryBySlug(post.category).badge}
-              </span>
+              {post.categories.map((category) => (
+                <span
+                  key={category}
+                  className="whitespace-nowrap border border-line-strong px-2.5 py-[3px] font-mono text-[11px] text-foreground/50 uppercase tracking-[0.02em]"
+                >
+                  {categoryBySlug(category).badge}
+                </span>
+              ))}
               <span className="font-mono text-[12px] text-foreground/40 uppercase tracking-[0.02em]">
                 {formatDate(post.date)}
               </span>

src/marketing/app/blog/_components/PostExplorer.tsx

@@ -12,7 +12,7 @@ type Filter = (typeof filters)[number]['slug']
 
 export default function PostExplorer({ posts }: { posts: PostMeta[] }) {
   const [active, setActive] = useState<Filter>('all')
-  const visible = active === 'all' ? posts : posts.filter((p) => p.category === active)
+  const visible = active === 'all' ? posts : posts.filter((p) => p.categories.includes(active))
 
   return (
     <section>
@@ -48,9 +48,14 @@ export default function PostExplorer({ posts }: { posts: PostMeta[] }) {
                 className="group flex flex-col gap-2.5 border-line border-b px-5 py-6 transition-colors hover:bg-surface-block lg:px-8"
               >
                 <span className="flex flex-wrap items-center gap-3">
-                  <span className="whitespace-nowrap border border-line-strong px-2.5 py-[3px] font-mono text-[11px] text-foreground/50 uppercase tracking-[0.02em]">
-                    {categoryBySlug(post.category).badge}
-                  </span>
+                  {post.categories.map((category) => (
+                    <span
+                      key={category}
+                      className="whitespace-nowrap border border-line-strong px-2.5 py-[3px] font-mono text-[11px] text-foreground/50 uppercase tracking-[0.02em]"
+                    >
+                      {categoryBySlug(category).badge}
+                    </span>
+                  ))}
                   {isNew(post.date) && (
                     <span className="whitespace-nowrap border border-indicator-green px-2.5 py-[3px] font-mono text-[11px] text-indicator-green uppercase tracking-[0.02em]">
                       New

src/marketing/app/blog/_lib/categories.ts

@@ -17,6 +17,7 @@ export type PostMeta = {
   excerpt: string
   date: string
   category: CategorySlug
+  categories: CategorySlug[]
   authors: string
   featured: boolean
 }

src/marketing/app/blog/_lib/posts.ts

@@ -10,6 +10,7 @@ export type Post = PostMeta & { html: string }
 const posts: Post[] = renderedPosts.map((post) => ({
   ...post,
   category: post.category as CategorySlug,
+  categories: post.categories as CategorySlug[],
 }))
 
 export function getAllPosts(): Post[] {

src/marketing/app/blog/page.tsx

@@ -17,6 +17,7 @@ export default function BlogPage() {
     excerpt: post.excerpt,
     date: post.date,
     category: post.category,
+    categories: post.categories,
     authors: post.authors,
     featured: post.featured,
   }))

src/marketing/blogPlugin.ts

@@ -10,7 +10,8 @@ import { unified } from 'unified'
 import type { Plugin } from 'vite'
 
 // Blog content lives as dev-managed markdown files in /blogs at the repo root.
-// Frontmatter schema: title, excerpt, date (YYYY-MM-DD), category, optional
+// Frontmatter schema: title, excerpt, date (YYYY-MM-DD), category (a slug or
+// inline list of slugs), optional
 // authors, and an optional `featured: true` to pin a post to the hero card.
 //
 // Markdown is rendered to HTML here, in Node, at build/dev time, so the heavy
@@ -66,6 +67,7 @@ export type RenderedPost = {
   excerpt: string
   date: string
   category: string
+  categories: string[]
   authors: string
   featured: boolean
   html: string
@@ -97,8 +99,9 @@ const processor = unified()
   .use(rehypeStringify)
 
 // Minimal frontmatter parser for our simple schema (quoted strings, an
-// unquoted YYYY-MM-DD date, a category slug, and an optional boolean). Avoids
-// pulling in gray-matter + js-yaml for a handful of known keys.
+// unquoted YYYY-MM-DD date, a category slug or inline list of slugs, and an
+// optional boolean). Avoids pulling in gray-matter + js-yaml for a handful of
+// known keys.
 function parseFrontmatter(raw: string): { data: Record<string, string>; content: string } {
   const match = /^---\r?\n([\s\S]*?)\r?\n---\r?\n?([\s\S]*)$/.exec(raw)
   if (!match) return { data: {}, content: raw }
@@ -123,14 +126,24 @@ function parseFrontmatter(raw: string): { data: Record<string, string>; content:
   return { data, content: match[2] }
 }
 
+function parseCategories(value: string): string[] {
+  const list = value.startsWith('[') && value.endsWith(']') ? value.slice(1, -1) : value
+  return list
+    .split(',')
+    .map((category) => category.trim().replace(/^(['"])(.*)\1$/, '$2'))
+    .filter(Boolean)
+}
+
 async function renderPost(filename: string): Promise<SearchablePost> {
   const slug = filename.replace(/\.md$/, '')
   const raw = fs.readFileSync(path.join(BLOGS_DIR, filename), 'utf8')
   const { data, content } = parseFrontmatter(raw)
 
-  if (!CATEGORY_SLUGS.includes(data.category)) {
+  const categories = [...new Set(parseCategories(data.category ?? ''))]
+  const unknownCategories = categories.filter((category) => !CATEGORY_SLUGS.includes(category))
+  if (categories.length === 0 || unknownCategories.length > 0) {
     throw new Error(
-      `blogs/${filename}: unknown category "${data.category}". ` +
+      `blogs/${filename}: unknown category "${unknownCategories[0] ?? data.category}". ` +
         `Expected one of: ${CATEGORY_SLUGS.join(', ')}`,
     )
   }
@@ -142,7 +155,8 @@ async function renderPost(filename: string): Promise<SearchablePost> {
     title: data.title,
     excerpt: data.excerpt,
     date: data.date,
-    category: data.category,
+    category: categories[0],
+    categories,
     authors: data.authors ?? '',
     featured: data.featured === 'true',
     html,

src/marketing/next.d.ts

@@ -9,6 +9,7 @@ declare module 'virtual:blog-posts' {
     excerpt: string
     date: string
     category: string
+    categories: string[]
     authors: string
     featured: boolean
     html: string