diff --git a/CHANGES.md b/CHANGES.md
index cc939d7349..26ac685fca 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -85,6 +85,9 @@ Changed:
   `nan != x` is always `true`. Use `float.is_nan` to test if a float is `nan`.
 - BREAKING: `replaygain` no longer takes `ebu_r128` parameter (#3438).
 - BREAKING: assume `replaygain_track_gain` always stores volume in _dB_ (#3438).
+- BREAKING: protocols can now check for nested static uri. Typically, this means
+  that requests for an uri of the form: `annotate:key="value",...:/path/to/file.mp3`
+  is now considered infallible if `/path/to/file.mp3` can be decoded.
 - Added `parents` option of `file.mkdir` (#3600, #3601).
 - Added `forced_major_collections` record field to the result of `runtime.gc.stat()` and
   `runtime.gc.quick_stat()` (#3783).
diff --git a/doc/content/migrating.md b/doc/content/migrating.md
index 6f6aca2361..3a99da33b5 100644
--- a/doc/content/migrating.md
+++ b/doc/content/migrating.md
@@ -120,6 +120,22 @@ for more details.
   However, EBU R128 data is now extracted directly from metadata when available.
   So `replaygain` cannot control the gain type via this parameter anymore.
 
+### Static requests
+
+Static requests detection can now work with nested requests.
+
+Typically, a request for this URI: `annotate:key="value",...:/path/to/file.mp3` will be
+considered static if `/path/to/file.mp3` can be decoded.
+
+Practically, this means that more source will now be considered infallible, for instance
+a `single` using the above uri.
+
+In most cases, this should improve the user experience when building new scripts and streaming
+systems.
+
+In rare cases where you actually wanted a fallible source, you can still pass `fallible=true` to e.g.
+the `single` operator or use the `fallible:` protocol.
+
 ### String functions
 
 Some string functions have been updated to account for string encoding. In particular, `string.length` and `string.sub` now assume that their
diff --git a/src/core/builtins/builtins_resolvers.ml b/src/core/builtins/builtins_resolvers.ml
index c1af3259e0..5499a047a5 100644
--- a/src/core/builtins/builtins_resolvers.ml
+++ b/src/core/builtins/builtins_resolvers.ml
@@ -133,6 +133,9 @@ let _ =
         { Playlist_parser.strict; Playlist_parser.parser = fn };
       Lang.unit)
 
+let default_static =
+  Lang.eval ~cache:false ~typecheck:false ~stdlib:`Disabled "fun (_) -> false"
+
 let _ =
   let log_p = [("", "", None)] in
   let log_t = Lang.fun_t [(false, "", Lang.string_t)] Lang.unit_t in
@@ -153,11 +156,12 @@ let _ =
         Some (Lang.bool false),
         Some "if true, file is removed when it is finished." );
       ( "static",
-        Lang.bool_t,
-        Some (Lang.bool false),
+        Lang.fun_t [(false, "", Lang.string_t)] Lang.bool_t,
+        Some default_static,
         Some
-          "if true, then requests can be resolved once and for all. Typically, \
-           static protocols can be used to create infallible sources." );
+          "When given an uri for the protocol, if it returns `true`, then \
+           requests can be resolved once and for all. Typically, static \
+           protocols can be used to create infallible sources." );
       ( "syntax",
         Lang.string_t,
         Some (Lang.string "Undocumented"),
@@ -185,7 +189,8 @@ let _ =
       let name = Lang.to_string (Lang.assoc "" 1 p) in
       let f = Lang.assoc "" 2 p in
       let temporary = Lang.to_bool (List.assoc "temporary" p) in
-      let static = Lang.to_bool (List.assoc "static" p) in
+      let static = List.assoc "static" p in
+      let static s = Lang.to_bool (Lang.apply static [("", Lang.string s)]) in
       let doc = Lang.to_string (List.assoc "doc" p) in
       let syntax = Lang.to_string (List.assoc "syntax" p) in
       Lang.add_protocol ~syntax ~doc ~static name (fun arg ~log timeout ->
diff --git a/src/core/doc.ml b/src/core/doc.ml
index 9d9afa045d..7604a93890 100644
--- a/src/core/doc.ml
+++ b/src/core/doc.ml
@@ -1 +1,22 @@
 include Liquidsoap_lang.Doc
+
+(** Documentation for protocols. *)
+module Protocol = struct
+  type t = { name : string; description : string; syntax : string }
+
+  let db = ref []
+
+  let add ~name ~doc ~syntax =
+    let p = { name; description = doc; syntax } in
+    db := p :: !db
+
+  let db () = List.sort compare !db
+  let count () = db () |> List.length
+
+  let print_md print =
+    List.iter
+      (fun p ->
+        Printf.ksprintf print "### %s\n\n%s\n\nThe syntax is `%s`.\n\n" p.name
+          p.description p.syntax)
+      (db ())
+end
diff --git a/src/core/lang.ml b/src/core/lang.ml
index a5904d4a60..cca49f0597 100644
--- a/src/core/lang.ml
+++ b/src/core/lang.ml
@@ -1,7 +1,6 @@
 include Liquidsoap_lang.Lang
 include Lang_source
 include Lang_encoder.L
-module Doc = Liquidsoap_lang.Doc
 module Flags = Liquidsoap_lang.Flags
 module Http = Liq_http
 
@@ -11,7 +10,7 @@ let () = Hooks_implementations.register ()
 (** Helpers for defining protocols. *)
 
 let add_protocol ~syntax ~doc ~static name resolver =
-  Doc.Protocol.add ~name ~doc ~syntax ~static;
+  Doc.Protocol.add ~name ~doc ~syntax;
   let spec = { Request.static; resolve = resolver } in
   Plug.register Request.protocols ~doc name spec
 
diff --git a/src/core/lang.mli b/src/core/lang.mli
index dfcf39091e..b933b25e1f 100644
--- a/src/core/lang.mli
+++ b/src/core/lang.mli
@@ -62,7 +62,7 @@ val apply : ?pos:Liquidsoap_lang.Pos.t list -> value -> env -> value
 val add_protocol :
   syntax:string ->
   doc:string ->
-  static:bool ->
+  static:(string -> bool) ->
   string ->
   Request.resolver ->
   unit
diff --git a/src/core/protocols/annotate.ml b/src/core/protocols/annotate.ml
index d5aafc5aca..0630dacd11 100644
--- a/src/core/protocols/annotate.ml
+++ b/src/core/protocols/annotate.ml
@@ -66,5 +66,10 @@ let annotate s ~log _ =
 
 let () =
   Lang.add_protocol ~doc:"Add metadata to a request"
-    ~syntax:"annotate:key=\"val\",key2=\"val2\",...:uri" ~static:false
+    ~syntax:"annotate:key=\"val\",key2=\"val2\",...:uri"
+    ~static:(fun uri ->
+      try
+        let _, uri = parse uri in
+        Request.is_static uri
+      with _ -> false)
     "annotate" annotate
diff --git a/src/core/protocols/mpd.ml b/src/core/protocols/mpd.ml
index c4d6ea7444..fae9a6e60e 100644
--- a/src/core/protocols/mpd.ml
+++ b/src/core/protocols/mpd.ml
@@ -146,4 +146,6 @@ let mpd s ~log _ =
 let () =
   Lang.add_protocol
     ~doc:"Finds all files with a tag equal to a given value using mpd."
-    ~syntax:"mpd:tag=value" ~static:false "mpd" mpd
+    ~syntax:"mpd:tag=value"
+    ~static:(fun _ -> false)
+    "mpd" mpd
diff --git a/src/core/request.ml b/src/core/request.ml
index 11407289be..e6c6c5cd31 100644
--- a/src/core/request.ml
+++ b/src/core/request.ml
@@ -610,7 +610,7 @@ let get_decoder ~ctype r =
 (** Plugins registration. *)
 
 type resolver = string -> log:(string -> unit) -> float -> indicator option
-type protocol = { resolve : resolver; static : bool }
+type protocol = { resolve : resolver; static : string -> bool }
 
 let protocols_doc =
   "Methods to get a file. They are the first part of URIs: 'protocol:args'."
@@ -621,9 +621,9 @@ let is_static s =
   if file_exists (home_unrelate s) then true
   else (
     match parse_uri s with
-      | Some (proto, _) -> (
+      | Some (proto, uri) -> (
           match Plug.get protocols proto with
-            | Some handler -> handler.static
+            | Some handler -> handler.static uri
             | None -> false)
       | None -> false)
 
diff --git a/src/core/request.mli b/src/core/request.mli
index f5052c6558..80a8bd68b5 100644
--- a/src/core/request.mli
+++ b/src/core/request.mli
@@ -100,7 +100,7 @@ val from_id : int -> t option
 type resolver = string -> log:(string -> unit) -> float -> indicator option
 
 (** A protocol, which can resolve associated URIs. *)
-type protocol = { resolve : resolver; static : bool }
+type protocol = { resolve : resolver; static : string -> bool }
 
 (** A static request [r] is such that every resolving leads to the same file.
     Sometimes, it allows removing useless destroy/create/resolve. *)
diff --git a/src/lang/doc.ml b/src/lang/doc.ml
index 90d23ded51..5e3588cbd5 100644
--- a/src/lang/doc.ml
+++ b/src/lang/doc.ml
@@ -62,33 +62,6 @@ module Plug = struct
   let print_string = print_md
 end
 
-(** Documentation for protocols. *)
-module Protocol = struct
-  type t = {
-    name : string;
-    description : string;
-    syntax : string;
-    static : bool;
-  }
-
-  let db = ref []
-
-  let add ~name ~doc ~syntax ~static =
-    let p = { name; description = doc; syntax; static } in
-    db := p :: !db
-
-  let db () = List.sort compare !db
-  let count () = db () |> List.length
-
-  let print_md print =
-    List.iter
-      (fun p ->
-        let static = if p.static then " This protocol is static." else "" in
-        Printf.ksprintf print "### %s\n\n%s\n\nThe syntax is `%s`.%s\n\n" p.name
-          p.description p.syntax static)
-      (db ())
-end
-
 (** Documenentation for values. *)
 module Value = struct
   (** Documentation flags. *)
diff --git a/src/libs/protocols.liq b/src/libs/protocols.liq
index 71d51c4990..afa8d7b1c4 100644
--- a/src/libs/protocols.liq
+++ b/src/libs/protocols.liq
@@ -388,6 +388,23 @@ protocol.add(
   syntax="tmp:uri"
 )
 
+# Register fallible
+# @flag hidden
+def protocol.fallible(~rlog=_, ~maxtime=_, arg) =
+  arg
+end
+
+protocol.add(
+  "fallible",
+  protocol.fallible,
+  doc=
+    "Mark the given uri as being fallible. This can be used to prevent a request \
+     or source from being resolved once and for all and considered infallible \
+     for the duration of the script, typically when debugging.",
+  static=fun (_) -> false,
+  syntax="fallible:uri"
+)
+
 let settings.protocol.ffmpeg = settings.make.protocol("FFmpeg")
 let settings.protocol.ffmpeg.path =
   settings.make(
@@ -651,7 +668,7 @@ def protocol.stereo(~rlog=_, ~maxtime=_, arg) =
 end
 
 protocol.add(
-  static=true,
+  static=fun (_) -> true,
   temporary=true,
   "stereo",
   protocol.stereo,
@@ -671,7 +688,7 @@ def protocol.copy(~rlog=_, ~maxtime=_, arg) =
 end
 
 protocol.add(
-  static=true,
+  static=fun (_) -> true,
   "copy",
   protocol.copy,
   doc=
@@ -699,7 +716,7 @@ def protocol.text2wave(~rlog=_, ~maxtime=_, arg) =
 end
 
 protocol.add(
-  static=true,
+  static=fun (_) -> true,
   "text2wave",
   protocol.text2wave,
   doc=
@@ -736,7 +753,7 @@ def protocol.pico2wave(~rlog=_, ~maxtime=_, arg) =
 end
 
 protocol.add(
-  static=true,
+  static=fun (_) -> true,
   "pico2wave",
   protocol.pico2wave,
   doc=
@@ -781,7 +798,7 @@ def protocol.gtts(~rlog=_, ~maxtime=_, arg) =
 end
 
 protocol.add(
-  static=true,
+  static=fun (_) -> true,
   "gtts",
   protocol.gtts,
   doc=
@@ -819,7 +836,7 @@ def protocol.macos_say(~rlog=_, ~maxtime=_, arg) =
 end
 
 protocol.add(
-  static=true,
+  static=fun (_) -> true,
   "macos_say",
   protocol.macos_say,
   doc=
@@ -846,7 +863,7 @@ def protocol.say(~rlog=_, ~maxtime=_, arg) =
 end
 
 protocol.add(
-  static=true,
+  static=fun (_) -> true,
   "say",
   protocol.say,
   doc=
@@ -993,7 +1010,7 @@ def polly_protocol(~rlog=_, ~maxtime=_, text) =
 end
 
 protocol.add(
-  static=true,
+  static=fun (_) -> true,
   "polly",
   polly_protocol,
   doc=
@@ -1070,7 +1087,7 @@ def synth_protocol(~rlog=_, ~maxtime=_, text) =
 end
 
 protocol.add(
-  static=true,
+  static=fun (_) -> true,
   temporary=true,
   "synth",
   synth_protocol,
@@ -1101,7 +1118,7 @@ def file_protocol(~rlog=_, ~maxtime=_, arg) =
 end
 
 protocol.add(
-  static=true,
+  static=fun (_) -> true,
   temporary=false,
   "file",
   file_protocol,
diff --git a/src/runtime/main.ml b/src/runtime/main.ml
index a376d47205..4691f0c774 100644
--- a/src/runtime/main.ml
+++ b/src/runtime/main.ml
@@ -21,7 +21,6 @@
  *****************************************************************************)
 
 module Runtime = Liquidsoap_lang.Runtime
-module Doc = Liquidsoap_lang.Doc
 module Environment = Liquidsoap_lang.Environment
 module Profiler = Liquidsoap_lang.Profiler
 module Queue = Liquidsoap_lang.Queues.Queue