@@ -0,0 +1,14 @@
+---
+'@objectstack/cli': patch
+---
+
+`os serve <config>`: a multi-package config now serves its flat `src/docs/` pages, under the package that owns the stack's manifest
+
+Clause-②: no
+
+A config boot (`os serve objectstack.config.ts`, with or without `--dev`, and no compiled artifact) of a stack that carries `packages[]`, such as one `composeStacks([…], { manifest: 'preserve' })` returns, did not serve the stack's own `src/docs/*.md` pages. The boot put them on the config's top level, and a config boot registers that config's package bodies, never its top level. `GET /api/v1/meta/doc` did not list them, and nothing warned. `os build` of the same project, booted as an artifact, served them.
+
+- **What changes.** The config boot places the flat pages where `os build` places them: on the body of the one `packages[]` entry whose id is the stack's `manifest.id`, after that package's own `src/<pkg>/docs/` pages. `GET /api/v1/meta/doc` now lists them under that package, as an artifact boot of the same project does.
+- **What stays the same.** A single-package config (no `packages[]`) serves its flat pages under its one package, as before. Each package's own `src/<pkg>/docs/` pages are served under that package, as before. Artifact boots (`os dev`, `os start`, `os serve` with `dist/objectstack.json`) do not change.
+- **When nothing moves.** If no entry has the manifest id, if several do, or if the stack declares no `manifest.id`, the flat pages stay on the top level, as `os build` keeps them. A config boot of such a stack still does not list them.
+- **A name shared by an inline doc and a flat page.** `os build` refuses this (`docs/duplicate-name`); a config boot does not lint docs. On a single-package config the flat page still replaces the inline doc of the same name. On a multi-package config the flat page is now served under the owning package, and an inline doc on that package's body with the same name is served with the flat page's content.
@@ -2513,22 +2513,35 @@ export default class Serve extends Command {
       // an artifact boot does. Leaving this half out would re-open the asymmetry
       // the paragraph above exists to close — `os build` producing docs that
       // `os dev` cannot show.
+      //
+      // [#22405] WHERE the flat set lands is `placeCollectedDocs`'s decision,
+      // the one `os build` makes: on a multi-package config it rides the body
+      // of the package whose id is the stack's `manifest.id`, because this boot
+      // registers package bodies and never the top level of such a config, so a
+      // flat doc left there is served by nothing and warned about by nothing.
+      // With no owner (no `packages[]`, or a `manifest.id` naming no single
+      // entry) it stays on the top level, exactly as before. Inline top-level
+      // docs never move; the name dedupe below runs only over what stays.
       if (!useArtifactFallback) {
         try {
-          const { collectDocsFromSrc, attachPackageDocs } = await import('../utils/collect-docs.js');
+          const { collectDocsFromSrc, placeCollectedDocs } = await import('../utils/collect-docs.js');
           const collected = collectDocsFromSrc(absolutePath, (config as any)?.packages);
-          if (collected.docs.length > 0) {
+          const inline = Array.isArray((config as any).docs) ? (config as any).docs : [];
+          // `collectDocsFromSrc`'s `docs` IS the flat set; the top-level set is
+          // inline first, as `collectAndLintDocs` returns it to `os build`.
+          const placed = placeCollectedDocs(config, {
+            docs: [...inline, ...collected.docs],
+            flatDocs: collected.docs,
+            packageDocs: collected.packageDocs,
+          });
+          if (collected.docs.length > 0 && placed.docs.length > 0) {
             const byName = new Map<string, any>();
-            for (const d of (Array.isArray((config as any).docs) ? (config as any).docs : [])) {
+            for (const d of placed.docs) {
               if (d?.name) byName.set(d.name, d);
             }
-            for (const d of collected.docs) byName.set(d.name, d);
             config = { ...config, docs: Array.from(byName.values()) };
           }
-          if (collected.packageDocs.length > 0) {
-            const packages = attachPackageDocs((config as any).packages, collected.packageDocs);
-            if (packages !== (config as any).packages) config = { ...config, packages };
-          }
+          if (placed.packages !== (config as any).packages) config = { ...config, packages: placed.packages };
         } catch {
           /* docs are additive — never block boot on collection */
         }
 
@@ -405,7 +405,7 @@ const READS: Readonly<Record<string, ReadRow>> = {
   },
   'commands/serve.ts :: config.docs': {
     reads: 'top-level',
-    why: 'the dev mirror of `os build`: the root `src/docs` collection joins the TOP-LEVEL `docs`, as `collectAndLintDocs` returns it for the artifact\'s top level, and each package\'s own docs are attached to that package\'s body (`attachPackageDocs`, beside it).',
+    why: 'the dev mirror of `os build`: the read is the top level\'s own inline `docs`, which never move. The root `src/docs` collection is placed by `placeCollectedDocs`, as `os build` places it: on the body of the package whose id is the stack\'s `manifest.id` on a multi-package stack, on the top level when no single package owns it, and each package\'s own docs on that package\'s body.',
   },
   // ── shared readers ─────────────────────────────────────────────────────
   'utils/authoring-filter-judge.ts :: stack': {