diff --git a/DESIGN_SHOW.md b/DESIGN_SHOW.md
index 205a519..2373d3c 100644
--- a/DESIGN_SHOW.md
+++ b/DESIGN_SHOW.md
@@ -33,7 +33,8 @@ roots, see below — `Url.resolve` passes `~roots:None`):
 
 ```ocaml
 let resolver =
-  Resolver.create ~important_digests:false ~directories ~open_modules:[] ~roots
+  Resolver.create ~important_digests:false ~directories
+    ~open_modules:["Stdlib"] ~roots
 in
 let reference =
   Odoc_model.Semantics.parse_reference s            (* string -> Reference.t *)
@@ -49,6 +50,12 @@ Odoc_xref2.Ref_tools.resolve_reference env reference
 `Identifier.t` of the target (the same step `url.ml` feeds to
 `Document.Url.from_identifier`).
 
+`~open_modules:["Stdlib"]` makes resolution behave as if `open Stdlib`, so a
+bare `List` or `print_endline` resolves — mirroring the compiler's (and the
+driver's link-time) default environment. `Env.open_units` looks each name up
+through the resolver and opens its signature; a module not documented in the
+switch is silently skipped.
+
 Note the second element of the result is only a *synopsis* paragraph (the
 first paragraph, used when expanding `{!ref}` inline). We want the whole doc
 comment, so we ignore it and fetch the docs separately.
diff --git a/README.md b/README.md
index 6652ccc..a9b2f9e 100644
--- a/README.md
+++ b/README.md
@@ -42,8 +42,9 @@ $ switchdocs setup --apply  # add it to ~/.opam/config via `opam option`
   single query covers the whole switch), printing each match with its owning
   package. `--package` restricts to named packages.
 - `switchdocs show REFERENCE` — print an item's documentation as Markdown,
-  resolving an odoc reference (e.g. `Stdlib.List.map`, `Astring.String`, or a
-  package-qualified `/stdlib/Stdlib.List.map`) against the whole switch.
+  resolving an odoc reference against the whole switch. `Stdlib` is open, so
+  bare names work (`List`, `print_endline`); references may also be qualified
+  (`Astring.String`) or package-qualified (`/stdlib/Stdlib.List.map`).
 
 ## Development
 
diff --git a/lib/show.ml b/lib/show.ml
index 81f528a..951708b 100644
--- a/lib/show.ml
+++ b/lib/show.ml
@@ -86,6 +86,12 @@ let scan sw =
 
 (* {1 Stage 2: resolve the reference} *)
 
+(* Resolve references as if these modules were open, mirroring the compiler's
+   (and the driver's link-time) default environment, so a bare [List] reaches
+   [Stdlib.List]. If a module isn't documented in the switch, [open_units]
+   simply skips it. *)
+let default_open = [ "Stdlib" ]
+
 let resolve_to_id { odoc; directories; page_roots; lib_roots; _ } ref_str =
   let dir = Odoc_odoc.Fs.Directory.of_string in
   let directories = List.map (fun d -> dir (Fpath.to_string d)) directories in
@@ -106,7 +112,7 @@ let resolve_to_id { odoc; directories; page_roots; lib_roots; _ } ref_str =
   in
   let resolver =
     Odoc_odoc.Resolver.create ~important_digests:false ~directories
-      ~open_modules:[] ~roots
+      ~open_modules:default_open ~roots
   in
   let warnings_options =
     {