diff --git a/content/(publish)/recipes/html.mdx b/content/(publish)/recipes/html.mdx
index 0dc825c0..9e365b60 100644
--- a/content/(publish)/recipes/html.mdx
+++ b/content/(publish)/recipes/html.mdx
@@ -41,7 +41,7 @@ Published: https://quiet-harbor.space.fast
   Files         4
 ```
 
-`about.html` answers `/about` as well as `/about.html`, because clean URLs are on by default. See [Redirects, rewrites, and headers](/routing) for that and for the `_redirects` and `_headers` files, which publish alongside your pages.
+`about.html` answers `/about`, and `/about.html` redirects there, because clean URLs are on by default. See [Redirects, rewrites, and headers](/routing) for that and for the `_redirects` and `_headers` files, which publish alongside your pages.
 
 ## The gotcha
 
diff --git a/content/(reference)/config-file.mdx b/content/(reference)/config-file.mdx
index cbc05dc4..721cf7df 100644
--- a/content/(reference)/config-file.mdx
+++ b/content/(reference)/config-file.mdx
@@ -96,14 +96,14 @@ While `name` is set in the file, the API refuses to rename the Space. The file w
 
 | Key | Type | Default | What it does |
 | --- | --- | --- | --- |
-| `index` | string or `false` | inferred, see below | The directory index file. `false` disables index resolution |
-| `fallback` | string, or `{ path, status }` | none | The committed file served when no exact route matches. `status` is 100 to 599 |
-| `cleanUrls` | boolean | `true`, unless a 200-status `fallback` is set | Serves `about.html` at `/about` |
+| `index` | string or `false` | inferred, see below | The homepage file `/` serves. Folders always serve their own `index.html`. `false` serves no homepage |
+| `fallback` | string, `false`, or `{ path, status }` | inferred for a single-page app, see below | The committed file served when no exact route matches. `status` is 100 to 599. `false` turns the inference off |
+| `cleanUrls` | boolean | `true` | Serves `about.html` at `/about`, ahead of any fallback |
 | `listing` | boolean | on when no index could be inferred and the version runs no worker | Automatic directory listings |
 
-`index` defaults to `index.html` when the version has one at the root. Otherwise, if the version publishes exactly one HTML file, that file. Otherwise, if there is exactly one HTML file at the root, that one. Otherwise `false`.
+`index` defaults to `index.html` when the version has one at the root. Otherwise, if a 200-status `fallback` names a committed file and the version runs no worker, that file. Otherwise, if the version publishes exactly one HTML file, that file. Otherwise, if there is exactly one HTML file at the root, that one. Otherwise `false`.
 
-`"fallback": { "path": "index.html", "status": 200 }` is the SPA declaration. It names the shell that owns every unresolved route, so it also turns `cleanUrls` and `listing` off unless you set them yourself. A `fallback` path that is not a committed file fails the publish.
+`"fallback": { "path": "index.html", "status": 200 }` is the SPA declaration. It names the shell that owns every unresolved route, so it turns `listing` off unless you set it yourself. Committed pages still answer their own URLs. With `"cleanUrls": false`, a flat `about.html` no longer answers `/about`, so that route reaches the shell. A `fallback` path that is not a committed file fails the publish. Left unset, `fallback` is inferred: a root `200.html`, else `_shell.html`, else a root `index.html` beside a build tool's output when there's no root `404.html`. See [SPA fallback](/routing#spa-fallback).
 
 ## Metadata and appearance
 
diff --git a/content/(serve)/routing.mdx b/content/(serve)/routing.mdx
index 3e2344cc..8a6d847d 100644
--- a/content/(serve)/routing.mdx
+++ b/content/(serve)/routing.mdx
@@ -209,18 +209,18 @@ There is no generic trailing-slash normalizer. The behavior comes from what the
 
 | Situation | Behavior |
 | --- | --- |
-| `dir/index.html` exists | `/dir/` serves, `/dir` answers 308 to `/dir/` |
+| `dir/index.html` exists | `/dir/` serves and `/dir` answers 308 to `/dir/`. With clean URLs on, `/dir/index` and `/dir/index.html` also redirect there |
 | A directory listing exists for `dir` | `/dir/` serves, `/dir` answers 308 to `/dir/` |
-| Clean URLs are on and `page.html` exists | `/page` serves, `/page/` answers 308 to `/page` |
+| Clean URLs are on and `page.html` exists | `/page` serves; `/page/` and `/page.html` answer 308 to `/page` |
 | Anything else | No normalization. The other spelling falls through to the SPA fallback or a 404 |
 
 Those compiled 308s accept every method and carry the incoming query across.
 
 ## Index files and clean URLs
 
-`index.html` at the root answers `/`. `docs/index.html` answers `/docs/`, and it keeps its literal `/docs/index.html` URL too.
+`index.html` at the root answers `/`. `docs/index.html` answers `/docs/`, and `/docs` redirects there with a 308. With clean URLs on, `/docs/index` and `/docs/index.html` also redirect there. A folder always serves its own `index.html`, the file every static site generator and framework writes for a folder.
 
-With no config, Spacefast infers the index: a root `index.html`, else a single public HTML file, else the one root-level HTML file, else none, which puts the Space in files mode with directory listings.
+With no `index` set, Spacefast infers the homepage: a root `index.html`, else the file a 200 `fallback` names (unless the version runs a worker, which keeps `/`), else a single public HTML file, else the one root-level HTML file, else none, which puts the Space in files mode with directory listings.
 
 Two keys in `sf.jsonc` change it:
 
@@ -231,9 +231,9 @@ Two keys in `sf.jsonc` change it:
 }
 ```
 
-`index` names the directory index file, defaulting to `index.html`. Setting it to `false` disables index resolution.
+`index` names the homepage, the file `/` serves. It doesn't rename folder indexes: with `"index": "home.html"`, `docs/home.html` doesn't answer `/docs/`, and the publish warns with `custom_index_not_folder_index`. Setting it to `false` serves no homepage.
 
-`cleanUrls` serves a flat `about.html` at `/about` as well as `/about.html`, and redirects `/about/` to `/about` with a 308. It defaults to on, unless a 200-status SPA fallback is configured, in which case it defaults to off.
+`cleanUrls` serves a flat `about.html` at `/about`, and redirects `/about.html` and `/about/` there with a 308, query string included. A rewrite that lands on `/about.html` still serves the file, and a page you address with your own redirect or `_headers` rule keeps its `.html` URL. With `"cleanUrls": false`, flat pages answer only at their file URL. Folders still serve their `index.html` at the folder URL: `/docs/` serves and `/docs` redirects there. The literal `/docs/index.html` also serves, while `/docs/index` has no generated alias. `cleanUrls` defaults to on, with or without a fallback, so a committed page always wins its URL over the SPA shell.
 
 In a config that declares `"version": 1`, these live under `serve` as `serve.index`, `serve.cleanUrls`, `serve.spaFallback`, and `serve.directoryListing`.
 
@@ -247,7 +247,15 @@ Without a `404.html`, Spacefast renders its own page: status 404, the heading "P
 
 ## SPA fallback
 
-Point `fallback` at a committed file to serve it whenever no exact route matches:
+A single-page app needs no config. When `fallback` isn't set and the version runs no worker, publish picks the shell from the files and says so with the note `spa_fallback_inferred`:
+
+1. A root `200.html`, the name Surge, SvelteKit, and Nuxt use.
+2. Otherwise `_shell.html`, which TanStack Start writes.
+3. Otherwise a root `index.html` next to a build tool's output, as long as there is no root `404.html`. That means `_app/`, `_next/static/`, `_nuxt/`, `asset-manifest.json`, or a script with a content hash in its name directly under `assets/` or under `static/js/`, such as `assets/index-DiwrgTda.js`. A hand-written `assets/app.js` doesn't count.
+
+A root `404.html` says routes can miss, so a static export that ships one keeps its real 404s. Files mode (`"listing": true` or `"index": false`) is never an SPA. Set `"fallback": false` to turn the inference off.
+
+Point `fallback` at a committed file to choose the shell yourself:
 
 ```jsonc sf.jsonc
 {
@@ -255,9 +263,11 @@ Point `fallback` at a committed file to serve it whenever no exact route matches
 }
 ```
 
-The long form takes a status: `{"path": "/index.html", "status": 200}`. Only `200` and `404` are accepted, and anything else resolves to 200. A bare string means 200. The path has to be a committed, non-private file, otherwise publish fails with `config_invalid`.
+The long form takes a status: `{"path": "/index.html", "status": 200}`. `false` serves no fallback, so a miss gets the nearest `404.html`. Only `200` and `404` are accepted, and anything else resolves to 200. A bare string means 200. The path has to be a committed, non-private file, otherwise publish fails with `config_invalid`.
+
+`{"path": "404.html", "status": 404}` is a custom error page, not an SPA fallback. A 200-status fallback is the SPA one. It turns directory listings off by default. When `index` isn't set, there's no root `index.html` and the version runs no worker, its file is also the homepage.
 
-`{"path": "404.html", "status": 404}` is a custom error page, not an SPA fallback. A 200-status fallback is the SPA one, and it turns clean URLs off by default and forces directory listings off.
+Committed files win over the fallback, as on Netlify, Vercel, and Cloudflare Pages. A framework that builds some routes as static pages and leaves the rest to a client-side shell needs no config beyond the fallback: `about.html` answers `/about`, `docs/index.html` answers `/docs/`, and every other route gets the shell. Set `"cleanUrls": false` and a flat `about.html` no longer answers `/about`, so that route reaches the shell; folders still serve their `index.html`.
 
 The fallback is skipped for around 110 asset extensions, including `css`, `js`, `json`, `png`, `svg`, `woff2`, `pdf` and `zip`, so a missing asset returns 404 instead of your HTML shell. It is a denylist on purpose, which keeps dotted client routes such as `/users/jane.doe` and `/v1.2.3` reaching the shell.