diff --git a/bin/forester/main.ml b/bin/forester/main.ml
index 759622b..f1b50a2 100644
--- a/bin/forester/main.ml
+++ b/bin/forester/main.ml
@@ -67,7 +67,7 @@ let build ~env _ config_path dev no_theme emit_legacy_xml =
         m "Parsed config file %s" config_path);
     let start_time = Unix.gettimeofday () in
     let forest = Forester.build_forest ~progress ~env ~dev ~config () in
-    State.iter_diagnostics (fun _ d -> List.iter Error.print d) forest;
+    State.iter_diagnostics (fun _ d -> List.iter (Error.print ~config) d) forest;
     if not no_theme then begin
       let theme_dir =
         Option.value
@@ -76,7 +76,7 @@ let build ~env _ config_path dev no_theme emit_legacy_xml =
       in
       match Eio_util.path_of_dir ~env theme_dir with
       | Ok path -> Forester.copy_contents_of_dir ~env ~forest path
-      | Error exn -> Error.(print @@ io_error exn)
+      | Error exn -> Error.(print ~config @@ io_error exn)
     end;
     Forester.render_forest ~progress ~forest ~emit_legacy_xml ();
     let elapsed = Unix.gettimeofday () -. start_time in
@@ -137,7 +137,9 @@ let index_tree_str =
 |}
 
 let init ~env dir =
-  let report = Result.iter_error Error.(io_error >>> print) in
+  let report =
+    Result.iter_error Error.(io_error >>> print ~config:(Config.default ()))
+  in
   let cwd =
     match dir with
     | None -> Eio.Stdenv.cwd env
diff --git a/flake.lock b/flake.lock
index 4b6b45b..8ead11a 100644
--- a/flake.lock
+++ b/flake.lock
@@ -70,11 +70,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1772542754,
-        "narHash": "sha256-WGV2hy+VIeQsYXpsLjdr4GvHv5eECMISX1zKLTedhdg=",
+        "lastModified": 1784796856,
+        "narHash": "sha256-wWFrV5/Qbm+lyt5x20E/bSbfJiGKMo4RCxZV8cl/WZI=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "8c809a146a140c5c8806f13399592dbcb1bb5dc4",
+        "rev": "e2587caef70cea85dd97d7daab492899902dbf5d",
         "type": "github"
       },
       "original": {
@@ -84,6 +84,54 @@
         "type": "github"
       }
     },
+    "nixpkgs-llvm17": {
+      "locked": {
+        "lastModified": 1723734425,
+        "narHash": "sha256-GwSfzmTMpM+gAJHURHNRle6AX9nhhdZnC41tC4AkvO8=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "35e0ed8d1875d2303fab9930c6eb205654a2f6a3",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "35e0ed8d1875d2303fab9930c6eb205654a2f6a3",
+        "type": "github"
+      }
+    },
+    "nixpkgs-python38": {
+      "locked": {
+        "lastModified": 1708815994,
+        "narHash": "sha256-hL7N/ut2Xu0NaDxDMsw2HagAjgDskToGiyZOWriiLYM=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "9a9dae8f6319600fa9aebde37f340975cab4b8c0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "9a9dae8f6319600fa9aebde37f340975cab4b8c0",
+        "type": "github"
+      }
+    },
+    "nixpkgs-python39": {
+      "locked": {
+        "lastModified": 1743938762,
+        "narHash": "sha256-UgFYn8sGv9B8PoFpUfCa43CjMZBl1x/ShQhRDHBFQdI=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "74a40410369a1c35ee09b8a1abee6f4acbedc059",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "74a40410369a1c35ee09b8a1abee6f4acbedc059",
+        "type": "github"
+      }
+    },
     "opam-nix": {
       "inputs": {
         "flake-compat": "flake-compat",
@@ -92,6 +140,9 @@
         "nixpkgs": [
           "nixpkgs"
         ],
+        "nixpkgs-llvm17": "nixpkgs-llvm17",
+        "nixpkgs-python38": "nixpkgs-python38",
+        "nixpkgs-python39": "nixpkgs-python39",
         "opam-overlays": "opam-overlays",
         "opam-repository": [
           "opam-repository"
@@ -99,11 +150,11 @@
         "opam2json": "opam2json"
       },
       "locked": {
-        "lastModified": 1771067167,
-        "narHash": "sha256-XSw8dQIkdr+6eLvbUHo3cJPtTU7o5SMODz3qlnzmGpQ=",
+        "lastModified": 1782476416,
+        "narHash": "sha256-oFdLuHny6fe6kSOrOTN5Bfls+GisFiM8ytYrBQpGRog=",
         "owner": "tweag",
         "repo": "opam-nix",
-        "rev": "2e20bbbe8130d1880338291446fd4e710a4db9a1",
+        "rev": "583fb2ed4db44fcda4f6222c554949503d50a352",
         "type": "github"
       },
       "original": {
@@ -131,11 +182,11 @@
     "opam-repository": {
       "flake": false,
       "locked": {
-        "lastModified": 1772577116,
-        "narHash": "sha256-2asop4QmRveafi6E4DzzLe9DgwZYmcQc6OBfP2sHFkU=",
+        "lastModified": 1785014707,
+        "narHash": "sha256-dubArXq3YZOnTZ/+F8tHL/6BLR3I7HsnRZaf4sgpj6Y=",
         "owner": "ocaml",
         "repo": "opam-repository",
-        "rev": "cbed368dbe42bcb41584964f7e491ddb3d77cc96",
+        "rev": "f15dbe6fae81b4f8d4c1e2d6a78e50ce2b723b12",
         "type": "github"
       },
       "original": {
@@ -153,11 +204,11 @@
         "systems": "systems_3"
       },
       "locked": {
-        "lastModified": 1749457947,
-        "narHash": "sha256-+QVm+HOYikF3wUhqSIV8qJbE/feSG+p48fgxIosbHS0=",
+        "lastModified": 1782276984,
+        "narHash": "sha256-rBGN9TERADPXiehNe1/9emO6QqYPrTwSoMdB+BVEWpM=",
         "owner": "tweag",
         "repo": "opam2json",
-        "rev": "0ecd66fc2bfb25d910522c990dd36412259eac1f",
+        "rev": "88b2a71f6e2df38d3304d3900ee129f4e83048f8",
         "type": "github"
       },
       "original": {
diff --git a/flake.nix b/flake.nix
index 7e96fbd..ac1e952 100644
--- a/flake.nix
+++ b/flake.nix
@@ -42,7 +42,7 @@
         on = opam-nix.lib.${system};
         devPackagesQuery = {
           ocaml-lsp-server = "*";
-          ocamlformat = "*";
+          ocamlformat = "0.29.0";
           alcotest = "*";
           odoc = "*";
         };
@@ -50,7 +50,10 @@
           ocaml-system = "*";
         };
         mkScopes = pkgs: isStatic: rec {
-          scope = on.buildDuneProject { inherit pkgs; } package ./. query;
+          scope = on.buildDuneProject {
+            inherit pkgs;
+            resolveArgs.env.sys-ocaml-version = pkgs.ocaml.version;
+          } package ./. query;
           overlay = final: prev: {
             ${package} = prev.${package}.overrideAttrs (
               _:
@@ -60,14 +63,14 @@
               // (
                 if isStatic then
                   {
-                    buildPhase = ''dune build -p ${package} --profile static -j $NIX_BUILD_CORES'';
+                    buildPhase = "dune build -p ${package} --profile static -j $NIX_BUILD_CORES";
                   }
                 else
                   { }
               )
             );
             ocamlgraph = prev.ocamlgraph.overrideAttrs (_: {
-              buildPhase = ''dune build -p ocamlgraph -j $NIX_BUILD_CORES'';
+              buildPhase = "dune build -p ocamlgraph -j $NIX_BUILD_CORES";
             });
             conf-gmp = prev.conf-gmp.overrideAttrs (_: {
               nativeBuildInputs = [ pkgs.pkgsBuildHost.stdenv.cc ];
@@ -108,7 +111,10 @@
             with pkgs;
             devPackages
             ++ [
-              esbuild
+              difftastic
+              libxslt
+              htmlhint
+              prettier
               tex
               reuse
               watchexec
diff --git a/lib/compiler/Driver.ml b/lib/compiler/Driver.ml
index 69ff92a..e0e25b7 100644
--- a/lib/compiler/Driver.ml
+++ b/lib/compiler/Driver.ml
@@ -23,7 +23,7 @@ let update ?(bail = true) ?(progress = Phases.no_progress) (action : Action.t)
     (Query_results r, forest)
   | Query_results _ -> (Done, forest)
   | Report_errors (errors, next_action) ->
-    List.iter Error.print errors;
+    List.iter (Error.print ~config:forest.config) errors;
     if Error.any_fatal errors then (Quit Fail, forest) else (next_action, forest)
   | Load_configured_dirs ->
     Phases.load_configured_dirs ~forest ~progress;
@@ -94,7 +94,7 @@ let batch_run ?(progress = Phases.no_progress) ~env ~(config : Config.t) ~dev ()
   let report action =
     match action with
     | Report_errors (e, _) ->
-      List.iter Error.print e;
+      List.iter (Error.print ~config) e;
       if Error.any_fatal e then exit 1
     | _ -> ()
   in
diff --git a/lib/compiler/Error.ml b/lib/compiler/Error.ml
index 20a30c1..1551be8 100644
--- a/lib/compiler/Error.ml
+++ b/lib/compiler/Error.ml
@@ -5,6 +5,23 @@ open struct
   module T = Types
 end
 
+type code =
+  [ `Eval_error
+  | `Type_error
+  | `Expand_error
+  | `Parse_error
+  | `Io_error
+  | `Config_error
+  | `LaTeX_error
+  | `Duplicate_tree
+  | `Unlinked_attribution
+  | `Broken_link
+  | `Broken_transclusion
+  | `Foreign_blob_error
+  | `Unresolved_import
+  | `Invalid_date
+  | `Invalid_uri ]
+
 type t =
   | Eval_error of Eval_error.t
   | Expand_error of Expand_error.t
@@ -24,17 +41,14 @@ type t =
 
 and latex_error = {range: Grace.Range.t; msg: string}
 
-and unlinked_attribution_warning = {
-  role: T.attribution_role;
-  range: Range.t option;
-}
+and unlinked_attribution_warning = T.(content attribution)
 
 let tex_range {range; _} = range
 let latex_error ~range msg = {range; msg}
 let of_tex_error e = LaTeX_error e
 
-let unlinked_attribution_warning ~range role =
-  Unlinked_attribution_warning {range; role}
+let unlinked_attribution_warning attribution =
+  Unlinked_attribution_warning attribution
 let broken_transclusion t = Broken_transclusion t
 let broken_link t = Broken_link t
 let duplicate_tree ~uri = Duplicate_tree uri
@@ -103,8 +117,6 @@ let render_type_error ~range Eval_error.{got; expected} =
       [Label.createf ~range ~priority:Primary "this is %s" (show_value got)]
     | None -> [empty_label ~range]
   in
-  (*let got_note = [Message.createf "this is %s" (show_value got)] in*)
-  let got_note = [] in
   let notes =
     match expected with
     | [] -> []
@@ -117,37 +129,62 @@ let render_type_error ~range Eval_error.{got; expected} =
       ]
   in
   let msg = Message.createf "mismatched type" in
-  Diagnostic.create Error ~code:`Type_error ~labels ~notes:(got_note @ notes)
-    msg
-
-(*
-          Diagnostic.Label.createf ~range ~priority:Diagnostic.Priority.Primary
-            "this value is of type %s, but expected something of type %a" got
-            (Format.pp_print_list Eval_error.pp_expected_value)
-            expected;
-            *)
+  Diagnostic.create Error ~code:`Type_error ~labels ~notes msg
 
 let render_eval_error Eval_error.{error; range} =
   let default_labels = [empty_label ~range] in
+  let label s = Diagnostic.Label.createf ~range ~priority:Primary "%s" s in
   match error with
   | Type_error err -> render_type_error ~range err
-  | Invalid_URI _ -> Diagnostic.createf Error ~labels:[] ~notes:[] ""
+  | Invalid_URI s ->
+    Diagnostic.createf ~code:`Invalid_uri Error ~labels:[label s] "Invalid URI"
   | Invalid_date _ ->
-    Diagnostic.createf ~labels:default_labels Error "Invalid date"
-  | Unbound_variable _ ->
-    Diagnostic.createf ~labels:default_labels Error "unbound variable"
+    Diagnostic.createf ~code:`Invalid_date
+      ~labels:[label "expected a date in the form of YYYY-MM-DD."]
+      Error "Failed to parse date"
+  | Unbound_variable name ->
+    Diagnostic.createf ~code:`Eval_error Error
+      ~labels:
+        [
+          Label.createf ~range ~priority:Primary
+            "no binding named %s is in scope" name;
+        ]
+      "unbound variable"
   | No_current_uri ->
-    Diagnostic.createf ~labels:default_labels Error "no current uri"
-  | Missing_arguments _ ->
-    Diagnostic.createf ~labels:default_labels Error "missing arguments"
-  | Unbound_method _ ->
-    Diagnostic.createf ~labels:default_labels Error "unbound method"
-  | Unbound_fluid_symbol _ ->
-    Diagnostic.createf ~labels:default_labels Error "unbound fluid symbol"
-  | Asset_error _ ->
-    Diagnostic.createf ~labels:default_labels Error "asset error"
+    Diagnostic.createf ~code:`Eval_error ~labels:default_labels Error
+      "no current uri"
+  | Missing_arguments n ->
+    Diagnostic.createf ~code:`Eval_error Error
+      ~labels:
+        [
+          Label.createf ~range ~priority:Primary
+            "this function expected %d more argument%s" n
+            (if n = 1 then "" else "s");
+        ]
+      "missing arguments"
+  | Unbound_method name ->
+    Diagnostic.createf ~code:`Eval_error Error
+      ~labels:[Label.createf ~range ~priority:Primary "no method named %s" name]
+      "unbound method"
+  | Unbound_fluid_symbol sym ->
+    Diagnostic.createf ~code:`Eval_error Error
+      ~labels:
+        [
+          Label.createf ~range ~priority:Primary "no fluid binding for %s"
+            (Symbol.show sym);
+        ]
+      "unbound fluid symbol"
+  | Asset_error err ->
+    let describe : Asset_router.Error.error -> string = function
+      | Not_found path -> Format.asprintf "no such file: %s" path
+      | No_content_address -> "this asset has no content address"
+      | Failed_to_hash -> "failed to hash this asset's content"
+    in
+    Diagnostic.createf ~code:`Eval_error Error
+      ~labels:[Label.createf ~range ~priority:Primary "%s" (describe err)]
+      "asset error"
   | Unresolved_identifier {suggestions; path} ->
-    Diagnostic.createf Error
+    Diagnostic.createf ~code:`Eval_error Error
       ~labels:[empty_label ~range]
       ~notes:suggestions "unresolved identifier %a" Trie.pp_path path
 
@@ -165,33 +202,42 @@ let render_io_error (e : Eio_util.IO_error.t) =
     | File_already_exists f -> "file " ^ f ^ " already exists"
     | IO_error s -> s
   in
-  Diagnostic.createf Error "io_error: %s" msg
+  Diagnostic.createf ~code:`Io_error Error "%s" msg
 
-let render_config_error (error : string list Config_error.t) =
+let render_config_error (error : string list Config_error.t) : code Diagnostic.t
+    =
+  let pp_path =
+    Format.(
+      pp_print_list ~pp_sep:(fun out _ -> fprintf out ".") pp_print_string)
+  in
   match error with
-  | Parse_error {range = _; msg = _} -> Diagnostic.createf Error "parse_error"
-  | Using_default (_, _) -> Diagnostic.createf Error "using default"
+  | Parse_error {range; msg} ->
+    Diagnostic.createf ~code:`Config_error Error
+      ~labels:[empty_label ~range]
+      "%s" msg
+  | Using_default (path, default) ->
+    Diagnostic.createf ~code:`Config_error Warning
+      "using default %a for option %a" pp_path default pp_path path
   | Unknown_option option ->
-    Diagnostic.createf Warning ~code:`Config_error "unknown options %a"
-      Format.(
-        pp_print_list ~pp_sep:(fun out _ -> fprintf out ".") pp_print_string)
+    Diagnostic.createf Warning ~code:`Config_error "unknown option %a" pp_path
       option
-  | Invalid_url _ -> Diagnostic.createf Error "invalid url"
+  | Invalid_url url ->
+    Diagnostic.createf ~code:`Config_error Error "invalid url %s" url
   | No_path_in_foreign_table ->
-    Diagnostic.createf Error "no path in foreign table"
+    Diagnostic.createf ~code:`Config_error Error "no path in foreign table"
   | Missing_dir s ->
     Diagnostic.createf ~code:`Config_error Error "directory %s does not exist" s
   | Missing_file s ->
     Diagnostic.createf ~code:`Config_error Error "file %s does not exist" s
 
 let render_latex_error ({range; msg} : latex_error) =
-  Diagnostic.create Error
+  Diagnostic.create Error ~code:`LaTeX_error
     ~labels:[Label.createf ~range ~priority:Primary ""]
     Message.(create msg)
 
 let render_broken_transclusion (t : T.transclusion) =
   Diagnostic.(
-    createf Warning
+    createf Warning ~code:`Broken_transclusion
       ~labels:
         (Option.fold t.range ~none:[] ~some:(fun range ->
              [Label.createf ~range ~priority:Primary "This tree was not found"]))
@@ -199,30 +245,45 @@ let render_broken_transclusion (t : T.transclusion) =
 
 let render_broken_link (link : _ T.link) =
   Diagnostic.(
-    createf Warning
+    createf Warning ~code:`Broken_link
       ~labels:
         (Option.fold link.range ~none:[] ~some:(fun range ->
              [Label.createf ~range ~priority:Primary "This tree was not found"]))
       "Broken link %a" URI.pp link.href)
 
 let render_unlinked_attribution_warning
-    ({range; role} : unlinked_attribution_warning) =
+    ({role; range; vertex} : unlinked_attribution_warning) =
   let corrected_attribution_code =
     match role with
     | Author -> "\\author/literal"
     | Contributor -> "\\contributor/literal"
   in
-  Diagnostic.createf Error
+  let arg =
+    match vertex with
+    | T.Uri_vertex uri ->
+      Option.value (URI.name uri) ~default:(Format.asprintf "%a" URI.pp uri)
+    | T.Content_vertex _ -> "..."
+  in
+  let suggestion = Format.asprintf "%s{%s}" corrected_attribution_code arg in
+  let notes =
+    [
+      Message.createf
+        "If there is a tree trees/%s.tree, you may use the shorthand %s \
+         instead of a full URI."
+        arg arg;
+    ]
+  in
+  Diagnostic.createf Warning ~code:`Unlinked_attribution ~notes
     ~labels:
       (fold_range ~range
          Message.(
            createf
              "Expected valid URI in attribution. Use `%s` instead if you \
               intend an unlinked attribution."
-             corrected_attribution_code))
-    "Unlinked attribution"
+             suggestion))
+    "Did you mean %s?" suggestion
 
-let render =
+let render ~(config : Config.t) =
   let open Grace.Diagnostic in
   function
   | Cant_eval_anonymous_tree -> failwith "todo: can't eval"
@@ -233,7 +294,8 @@ let render =
   | Configuration_error error -> render_config_error error
   | LaTeX_error error -> render_latex_error error
   | Duplicate_tree uri ->
-    Diagnostic.createf Error "duplicate tree %a" URI.pp uri
+    Diagnostic.createf Error ~code:`Duplicate_tree "duplicate tree %a" URI.pp
+      uri
   | Broken_link link -> render_broken_link link
   | Broken_transclusion t -> render_broken_transclusion t
   | Unlinked_attribution_warning w -> render_unlinked_attribution_warning w
@@ -246,8 +308,8 @@ let render =
            you are using.";
       ]
     in
-    createf ~labels ~notes Error "Failed to load foreign blob %s: %s" s.path
-      s.msg
+    createf ~labels ~notes Error ~code:`Foreign_blob_error
+      "Failed to load foreign blob %s: %s" s.path s.msg
   | Failed_to_parse_foreign_blob s ->
     let labels = [] in
     let notes =
@@ -257,40 +319,51 @@ let render =
            you are using.";
       ]
     in
-    createf ~labels ~notes Error "Failed to parse foreign blob %s: %s" s.path
-      s.msg
+    createf ~labels ~notes Error ~code:`Foreign_blob_error
+      "Failed to parse foreign blob %s: %s" s.path s.msg
   | Failed_to_add_edge (_, _) -> failwith "failed to add edge"
   | Failed_to_add_vertex (range, uri) ->
     let name = Option.get @@ URI.(name uri) in
     let labels =
+      [Label.createf ~range ~priority:Primary "No file %s.tree found." name]
+    in
+    let notes =
       [
-        Label.create ~range ~priority:Primary
-          Message.(createf "No file %s.tree found." name);
+        Message.createf "checked the following directories: %a"
+          Format.(
+            pp_print_list
+              ~pp_sep:(fun out _ -> fprintf out ", ")
+              pp_print_string)
+          config.trees;
       ]
     in
-    createf ~labels Error "Unresolved import"
+    createf ~labels ~notes Error ~code:`Unresolved_import ""
 
-(*
-    let corrected = "\\tag/content" in
-    Diagnostic.createf Error
-      "Expected valid URI in tag. Use `%s` instead if you intend an unlinked \
-       attribution."
-      corrected
-      *)
+let code_to_string : code -> string = function
+  | `Eval_error -> "eval_error"
+  | `Type_error -> "type_error"
+  | `Expand_error -> "expand_error"
+  | `Parse_error -> "parse_error"
+  | `Io_error -> "io_error"
+  | `Config_error -> "config_error"
+  | `LaTeX_error -> "latex_error"
+  | `Duplicate_tree -> "duplicate_tree"
+  | `Unlinked_attribution -> "unlinked_attribution"
+  | `Broken_link -> "broken_link"
+  | `Broken_transclusion -> "broken_transclusion"
+  | `Foreign_blob_error -> "foreign"
+  | `Unresolved_import -> "unresolved_import"
+  | `Invalid_date -> "invalid_date"
+  | `Invalid_uri -> "invalid_uri"
 
 let print_diagnostic =
   let config =
     Grace_ansi_renderer.Config.{default with num_contextual_lines = 3}
   in
-  let code_to_string = function
-    | `Config_error -> "config_error"
-    | `Type_error -> "type_error"
-    | `Parse_error -> "parse_error"
-  in
   Format.eprintf "%a@."
     Grace_ansi_renderer.(pp_diagnostic ~config ~code_to_string)
 
-let print error = print_diagnostic (render error)
+let print ~config error = print_diagnostic (render ~config error)
 
 let is_fatal = function
   | Broken_link _ | Broken_transclusion _ -> false
@@ -304,4 +377,4 @@ let is_fatal = function
 
 let any_fatal = List.fold_left (fun acc x -> acc || is_fatal x) false
 
-let print_config_error error = print @@ config_error error
+let print_config_error error = print_diagnostic (render_config_error error)
diff --git a/lib/compiler/Error.mli b/lib/compiler/Error.mli
index 9b5a89a..bfa4ae1 100644
--- a/lib/compiler/Error.mli
+++ b/lib/compiler/Error.mli
@@ -5,10 +5,24 @@ module T := Types
 
 type latex_error
 
-type unlinked_attribution_warning = {
-  role: T.attribution_role;
-  range: Range.t option;
-}
+type code =
+  [ `Eval_error
+  | `Type_error
+  | `Expand_error
+  | `Parse_error
+  | `Io_error
+  | `Config_error
+  | `LaTeX_error
+  | `Duplicate_tree
+  | `Unlinked_attribution
+  | `Broken_link
+  | `Broken_transclusion
+  | `Foreign_blob_error
+  | `Unresolved_import
+  | `Invalid_date
+  | `Invalid_uri ]
+
+type unlinked_attribution_warning = T.(content attribution)
 
 type t =
   | Eval_error of Eval_error.t
@@ -34,15 +48,14 @@ val any_fatal : t list -> bool
 val tex_range : latex_error -> Range.t
 val latex_error : range:Grace.Range.t -> string -> latex_error
 
-val unlinked_attribution_warning :
-  range:Range.t option -> T.attribution_role -> t
+val unlinked_attribution_warning : unlinked_attribution_warning -> t
 val broken_transclusion : T.transclusion -> t
 val broken_link : T.(content link) -> t
 val cant_eval_anonymous_tree : t
 val failed_to_load_foreign_blob : msg:string -> path:string -> t
 val failed_to_parse_foreign_blob : msg:string -> path:string -> t
 
-val print : t -> unit
+val print : config:Config.t -> t -> unit
 val config_error : string list Config_error.t -> t
 val parse_error : Parse.error -> t
 val io_error : Eio_util.IO_error.t -> t
@@ -57,8 +70,9 @@ val yield : t -> unit
 val yield_eval_error : Eval_error.t -> unit
 val yield_expand_error : Expand_error.t -> unit
 
-val render : t -> [`Type_error | `Config_error | `Parse_error] Diagnostic.t
-val print_diagnostic :
-  [`Type_error | `Config_error | `Parse_error] Diagnostic.t -> unit
+val render : config:Config.t -> t -> code Diagnostic.t
+val render_config_error : string list Config_error.t -> code Diagnostic.t
+val code_to_string : code -> string
+val print_diagnostic : code Diagnostic.t -> unit
 
 val print_config_error : string list Config_error.t -> unit
diff --git a/lib/compiler/Eval.ml b/lib/compiler/Eval.ml
index 8e5b584..0475bfe 100644
--- a/lib/compiler/Eval.ml
+++ b/lib/compiler/Eval.ml
@@ -270,8 +270,8 @@ and eval_node ~env ({value; range} as node) : (Value.t, Eval_error.t) result =
     focus_clo ~env ~range env.lex_env
       (List.map (fun (info, x) -> (info, Some x)) xs)
       body
-  | Ref -> begin
-    match eval_pop_arg ~env ~range |> Result.bind @~ extract_uri ~env with
+  | Ref ->
+    begin match eval_pop_arg ~env ~range |> Result.bind @~ extract_uri ~env with
     | Ok {value = href; range} ->
       let content =
         T.Content
@@ -286,10 +286,17 @@ and eval_node ~env ({value; range} as node) : (Value.t, Eval_error.t) result =
       let got = None in
       let expected = [URI] in
       type_error ~got ~expected ~range
-  end
+    end
   | Link {title; dest} ->
+    let range_of_nodes : Syn.t -> Range.t option = function
+      | [] -> None
+      | first :: _ as nodes ->
+        let last = List.nth nodes (List.length nodes - 1) in
+        Some (Range.merge first.range last.range)
+    in
     let* value = eval_tape ~env dest in
-    let dest = {node with value} in
+    let dest_range = Option.value (range_of_nodes dest) ~default:range in
+    let dest = Range.{value; range = dest_range} in
     let* {value = href; range} = extract_uri ~env dest in
     let* content =
       match title with
@@ -690,7 +697,7 @@ and eval_node ~env ({value; range} as node) : (Value.t, Eval_error.t) result =
       | `Uri -> begin
         let* {value = uri; _} = extract_uri ~env arg in
         ok @@ T.Uri_vertex uri
-      end
+        end
     in
     focus ~env ~range:node.range @@ Dx_const const
   | Dx_execute ->
@@ -715,7 +722,7 @@ and focus ~env ~range = function
     | Content content' ->
       ok @@ Value.Content (T.concat_compressed_content content content')
     | value -> ok value
-  end
+    end
   | ( Sym _ | Obj _ | Dx_prop _ | Dx_sequent _ | Dx_query _ | Dx_var _
     | Dx_const _ ) as v -> begin
     let* c = process_tape ~env in
@@ -725,7 +732,7 @@ and focus ~env ~range = function
       let expected = [Content] in
       let got = Some v' in
       type_error ~got ~expected ~range
-  end
+    end
 
 and focus_clo ~env ~range rho (xs : string option binding list) body =
   match xs with
@@ -733,8 +740,8 @@ and focus_clo ~env ~range rho (xs : string option binding list) body =
     Result.bind
       (eval_tape ~env:{env with lex_env = rho} body)
       (focus ~env ~range)
-  | (info, y) :: ys -> begin
-    match pop_arg_opt ~env with
+  | (info, y) :: ys ->
+    begin match pop_arg_opt ~env with
     | Some arg ->
       let* yval =
         match info with
@@ -751,8 +758,8 @@ and focus_clo ~env ~range rho (xs : string option binding list) body =
       | Content nodes when T.strip_whitespace nodes = T.Content [] ->
         ok @@ Value.Clo (rho, xs, body)
       | _ -> missing_argument ~range (List.length xs)
+      end
     end
-  end
 
 and emit_content_nodes ~env ~range content =
   focus ~env ~range @@ Content (T.Content (T.compress_nodes content))
diff --git a/lib/compiler/Expand.ml b/lib/compiler/Expand.ml
index 2b30fac..fa372c0 100644
--- a/lib/compiler/Expand.ml
+++ b/lib/compiler/Expand.ml
@@ -200,12 +200,12 @@ let rec expand_eff ~(forest : State.t) : Code.t -> Syn.t = function
     | Call (obj, meth) ->
       let obj = expand_eff ~forest obj in
       {node with value = Call (obj, meth)} :: expand_eff ~forest rest
-    | Import (vis, dep) ->
+    | Import (vis, {value = dep; range = dep_range}) ->
       let dep_uri = URI.named_uri ~base:forest.config.url dep in
       begin match forest./{dep_uri} with
       | None ->
-        let range = node.range in
-        Error.yield_expand_error @@ Expand_error.import_not_found ~range dep_uri
+        Error.yield_expand_error
+        @@ Expand_error.import_not_found ~range:dep_range dep_uri
       | Some tree -> begin
         match vis with
         | Public -> Sc.include_subtree [] tree
diff --git a/lib/compiler/Expand_error.ml b/lib/compiler/Expand_error.ml
index 6f180e8..a3d2283 100644
--- a/lib/compiler/Expand_error.ml
+++ b/lib/compiler/Expand_error.ml
@@ -24,11 +24,17 @@ let render_unresolved_xmlns ~range prefix =
     ]
   in
   let labels = [Label.createf ~range ~priority:Primary ""] in
-  Diagnostic.createf Error ~labels ~notes "Unresolved XML namespace"
+  Diagnostic.createf Error ~code:`Expand_error ~labels ~notes
+    "Unresolved XML namespace"
 
 let render {range; error} =
   match error with
-  | Import_not_found _uri -> Diagnostic.createf Error {|import not found |}
+  | Import_not_found uri ->
+    Diagnostic.createf Error ~code:`Expand_error
+      ~labels:[Label.createf ~range ~priority:Primary "not found"]
+      "import not found: %a" URI.pp uri
   | Unresolved_identifier ->
-    Diagnostic.createf Error "todo: Expand_error.render"
+    Diagnostic.createf Error ~code:`Expand_error
+      ~labels:[Label.createf ~range ~priority:Primary ""]
+      "unresolved identifier"
   | Unresolved_xmlns prefix -> render_unresolved_xmlns ~range prefix
diff --git a/lib/compiler/Forester_compiler.ml b/lib/compiler/Forester_compiler.ml
index 2d6d3de..1b59cab 100644
--- a/lib/compiler/Forester_compiler.ml
+++ b/lib/compiler/Forester_compiler.ml
@@ -29,6 +29,8 @@ module Expand = Expand
     {{!Forester_core.Forest_graph.topo_fold}folding} over the
     {{!Forester_core.Forest_graph}import graph.}*)
 
+module Expand_error = Expand_error
+
 module Eval = Eval
 (** Transform {!Syn.tree}s into {{!Forester_core.Types.article}[articles]}.*)
 
@@ -68,6 +70,7 @@ module Job = Job
 (**/**)
 
 module Config_parser = Config_parser
+module Config_error = Config_error
 module Eio_util = Eio_util
 module Export_for_test = Export_for_test
 module Cache = Cache
diff --git a/lib/compiler/Imports.ml b/lib/compiler/Imports.ml
index 8656b94..719b068 100644
--- a/lib/compiler/Imports.ml
+++ b/lib/compiler/Imports.ml
@@ -43,11 +43,11 @@ and analyse_code ~env ~root (code : Code.t) =
 and analyse_node ~env ~root (node : Code.node Range.located) : unit =
   let config = env.forest.config in
   match node.value with
-  | Import (_, dep) ->
+  | Import (_, {value = dep; range = dep_range}) ->
     let dep_uri = URI.named_uri ~base:config.url dep in
     let dependency = T.Uri_vertex dep_uri in
     let target = T.Uri_vertex root in
-    begin match add_vertex ~env ~range:node.range dependency with
+    begin match add_vertex ~env ~range:dep_range dependency with
     | Ok () -> begin
       match add_edge env.graph dependency target with
       | Ok () -> ()
diff --git a/lib/compiler/Suggestions.ml b/lib/compiler/Suggestions.ml
index e717180..020c4ca 100644
--- a/lib/compiler/Suggestions.ml
+++ b/lib/compiler/Suggestions.ml
@@ -32,15 +32,15 @@ let create_suggestions ~visible path : Diagnostic.Message.t list =
       let path, data, _ = List.hd suggestions in
       let location_hint =
         match data with
-        | Syn.Term ({range; _} :: _) -> begin
-          match Range.source range with
+        | Syn.Term ({range; _} :: _) ->
+          begin match Range.source range with
           | `File name | `Reader {name = Some name; _} ->
             [Diagnostic.Message.createf "defined in %s" name]
           | _ -> []
-        end
+          end
         | _ -> []
       in
-      [Diagnostic.Message.createf "Did you mean %a?" Trie.pp_path path]
+      [Diagnostic.Message.createf "Did you mean \\%a?" Trie.pp_path path]
       @ location_hint
     else []
   in
diff --git a/lib/core/Code.ml b/lib/core/Code.ml
index 466b723..eae8b09 100644
--- a/lib/core/Code.ml
+++ b/lib/core/Code.ml
@@ -41,7 +41,7 @@ type node =
   | Object of t _object
   | Patch of t patch
   | Call of t * string
-  | Import of visibility * string
+  | Import of visibility * string Range.located
   | Def of Trie.path * string binding list * t
   | Decl_xmlns of string * string
   | Alloc of Trie.path
diff --git a/lib/core/Code.mli b/lib/core/Code.mli
index b378e23..edc5246 100644
--- a/lib/core/Code.mli
+++ b/lib/core/Code.mli
@@ -26,7 +26,7 @@ type node =
   | Object of t _object
   | Patch of t patch
   | Call of t * string
-  | Import of visibility * string
+  | Import of visibility * string Range.located
   | Def of Trie.path * string binding list * t
   | Decl_xmlns of string * string
   | Alloc of Trie.path
@@ -60,8 +60,8 @@ type tree = {source_path: string option; uri: URI.t option; code: t}
 val parens : t -> node
 val squares : t -> node
 val braces : t -> node
-val import_private : string -> node
-val import_public : string -> node
+val import_private : string Range.located -> node
+val import_public : string Range.located -> node
 val inline_math : t -> node
 val display_math : t -> node
 val map : (t -> t) -> node -> node
diff --git a/lib/frontend/Forester.ml b/lib/frontend/Forester.ml
index 44b6925..ac32a81 100644
--- a/lib/frontend/Forester.ml
+++ b/lib/frontend/Forester.ml
@@ -214,7 +214,7 @@ let render_forest ?(progress = Phases.no_progress) ~emit_legacy_xml
   in
   forest.log.debug ~src:Log.Src.frontend (fun m ->
       m "Writing %i files to output" (List.length jobs));
-  List.iter Error.print errors;
+  List.iter (Error.print ~config:forest.config) errors;
   begin
     (* Note: this part appears to be fast! *)
     let@ items = Eio.Fiber.List.iter ~max_fibers:20 @~ jobs in
diff --git a/lib/frontend/Html_client.ml b/lib/frontend/Html_client.ml
index 3b8bbd7..57fb24d 100644
--- a/lib/frontend/Html_client.ml
+++ b/lib/frontend/Html_client.ml
@@ -513,8 +513,8 @@ and render_attribution_vertex ~env (attribution : T.(content attribution)) =
     | Ok node -> node
     | Error (node, error) -> begin
       match error with
-      | `Broken_link {range; _} ->
-        Error.(yield @@ unlinked_attribution_warning ~range attribution.role);
+      | `Broken_link _ ->
+        Error.(yield @@ unlinked_attribution_warning attribution);
         node
     end
   end
@@ -868,10 +868,10 @@ let render_page ~forest ?(mode = Static)
       | Some uri ->
         if URI.Set.mem uri forest.broken_links then ()
         else begin
-          Error.print error;
+          Error.print ~config:forest.config error;
           forest.broken_links <- URI.Set.add uri forest.broken_links
         end
-      | None -> Error.print error)
+      | None -> Error.print ~config:forest.config error)
     errors;
   (Option.get !result, List.of_seq errors)
 
diff --git a/lib/frontend/Legacy_xml_client.ml b/lib/frontend/Legacy_xml_client.ml
index 472d77a..0b431b9 100644
--- a/lib/frontend/Legacy_xml_client.ml
+++ b/lib/frontend/Legacy_xml_client.ml
@@ -249,7 +249,7 @@ and render_transclusion ~env (transclusion : T.transclusion) : P.node list =
   match State.get_content_of_transclusion ~forest:env.forest transclusion with
   | None ->
     let warning = Error.broken_transclusion transclusion in
-    Error.print warning;
+    Error.print ~config:env.forest.config warning;
     []
   | Some content -> render_content ~env content
 
diff --git a/lib/frontend/test/config.t b/lib/frontend/test/config.t
index a1bf37b..a290348 100644
--- a/lib/frontend/test/config.t
+++ b/lib/frontend/test/config.t
@@ -6,7 +6,7 @@
   warning: option [forest.home] not set, using default index
 
   $ parse_forester_config configs/uninterpreted-fields.toml
-  warning[config_error]: unknown options forest.unknown
+  warning[config_error]: unknown option forest.unknown
 
   $ parse_forester_config configs/nonexistent.toml
   error[config_error]: file configs/nonexistent.toml does not exist
diff --git a/lib/language_server/Analysis.ml b/lib/language_server/Analysis.ml
index 03c7a41..9e80fc7 100644
--- a/lib/language_server/Analysis.ml
+++ b/lib/language_server/Analysis.ml
@@ -55,9 +55,9 @@ let extract_addr ({value; range} : Code.node Range.located) =
   match value with
   | Group (Braces, [{value = Text addr; _}])
   | Group (Parens, [{value = Text addr; _}])
-  | Text addr (* SEEEMS DODGY!! *)
-  | Import (_, addr) ->
+  | Text addr (* SEEEMS DODGY!! *) ->
     Some Range.{value = addr; range}
+  | Import (_, {value = addr; _}) -> Some Range.{value = addr; range}
   | Subtree (addr, _) -> Option.map (fun s -> Range.{value = s; range}) addr
   | _ -> None
 
diff --git a/lib/language_server/Diagnostics.ml b/lib/language_server/Diagnostics.ml
index fe53e9e..a58199c 100644
--- a/lib/language_server/Diagnostics.ml
+++ b/lib/language_server/Diagnostics.ml
@@ -30,4 +30,5 @@ let compute (document : Lsp.Text_document.t) =
   | diagnostics ->
     Eio.traceln "publishing %i diagnostics to %s" (List.length diagnostics)
       (Lsp.Uri.to_path lsp_uri);
-    Publish.publish lsp_uri @@ List.map Error.render diagnostics
+    Publish.publish lsp_uri
+    @@ List.map (Error.render ~config:forest.config) diagnostics
diff --git a/lib/language_server/Publish.ml b/lib/language_server/Publish.ml
index 1436090..074ee67 100644
--- a/lib/language_server/Publish.ml
+++ b/lib/language_server/Publish.ml
@@ -7,7 +7,6 @@
 
 open Forester_core
 open Forester_compiler
-open State.Syntax
 
 open struct
   module L = Lsp.Types
@@ -27,32 +26,32 @@ let render_lsp_related_info (uri : L.DocumentUri.t) (label : Diagnostic.Label.t)
   let message = Format.asprintf "%a" Diagnostic.Message.pp label.message in
   L.DiagnosticRelatedInformation.create ~location ~message
 
-let render_lsp_diagnostic (uri : L.DocumentUri.t) (diag : 'a Diagnostic.t) :
-    Lsp_Diagnostic.t =
-  let range = Lsp_shims.lsp_range_of_range @@ (List.hd diag.labels).range in
+let lsp_code_of_code (code : Error.code) : Jsonrpc.Id.t =
+  `String (Error.code_to_string code)
+
+let render_lsp_diagnostic (uri : L.DocumentUri.t)
+    (diag : Error.code Diagnostic.t) : Lsp_Diagnostic.t =
+  let range =
+    match diag.labels with
+    | label :: _ -> Lsp_shims.lsp_range_of_range label.range
+    | [] ->
+      let start = L.Position.create ~line:0 ~character:0 in
+      L.Range.create ~start ~end_:start
+  in
   let severity =
     Lsp_shims.Diagnostic.lsp_severity_of_severity @@ diag.severity
   in
-  let code =
-    `String "todo"
-    (*diag.code*)
-  in
-  let source =
-    let Lsp_state.{forest; _} = Lsp_state.get () in
-    let uri = URI.of_lsp_uri ~base:forest.config.url uri in
-    let@ doc = Option.map @~ Option.bind forest.={uri} Tree.document in
-    Lsp.Text_document.text doc
-  in
+  let code = Option.map lsp_code_of_code diag.code in
   let message = Format.asprintf "%a" Diagnostic.Message.pp diag.message in
   let relatedInformation = List.map (render_lsp_related_info uri) diag.labels in
-  Lsp_Diagnostic.create ~range ~severity ~code ?source
+  Lsp_Diagnostic.create ~range ~severity ?code ~source:"forester"
     ~message:(`String message) ~relatedInformation ()
 
 let broadcast notif =
   let msg = Broadcast.to_jsonrpc notif in
   send @@ RPC.Packet.Notification msg
 
-let publish (uri : Lsp.Uri.t) (diagnostics : 'a Diagnostic.t list) =
+let publish (uri : Lsp.Uri.t) (diagnostics : Error.code Diagnostic.t list) =
   let diagnostics = List.map (render_lsp_diagnostic uri) diagnostics in
   let params = L.PublishDiagnosticsParams.create ~uri ~diagnostics () in
   broadcast @@ PublishDiagnostics params
diff --git a/lib/parser/Grammar.mly b/lib/parser/Grammar.mly
index eb748ba..4e0b445 100644
--- a/lib/parser/Grammar.mly
+++ b/lib/parser/Grammar.mly
@@ -61,7 +61,7 @@ let patch_bindings :=
 let head_node :=
 | DEF; (~,~,~) = fun_spec; <Code.Def>
 | ALLOC; ~ = ident; <Code.Alloc>
-| EXPORT; ~ = txt_arg; <Code.import_public>
+| EXPORT; ~ = located_txt_arg; <Code.import_public>
 | NAMESPACE; ~ = ident; ~ = braces(code_expr); <Code.Namespace>
 | SUBTREE; ~ = option(squares(wstext)); ~ = braces(ws_list(locate(head_node))); <Code.Subtree>
 | FUN; ~ = binder; ~ = arg; <Code.Fun>
@@ -114,11 +114,12 @@ let arg :=
   { [{located_str with value = Code.Verbatim located_str.value}] }
 
 let txt_arg == braces(wstext)
+let located_txt_arg == braces(locate(wstext))
 let fun_spec == ~ = ident; ~ = binder; ~ = arg; <>
 
 let head_node_or_import :=
 | head_node
-| IMPORT; ~ = txt_arg; <Code.import_private>
+| IMPORT; ~ = located_txt_arg; <Code.import_private>
 
 let main :=
 | ~ = ws_list(locate(head_node_or_import)); EOF; <>
diff --git a/lib/server/Server.ml b/lib/server/Server.ml
index a9379d8..9836c3e 100644
--- a/lib/server/Server.ml
+++ b/lib/server/Server.ml
@@ -213,7 +213,7 @@ let config_handler ~env request_headers request_body forest =
          the user enters ~/forest/forest.toml *)
       match Config_parser.parse_forest_config_file ~env filename with
       | Error errs ->
-        let errors = List.map Error.(config_error >>> render) errs in
+        let errors = List.map Error.render_config_error errs in
         let errors =
           List.map
             (Format.asprintf "%a@."
diff --git a/test/bad-foreign-blob.t b/test/bad-foreign-blob.t
index d08699a..734d20d 100644
--- a/test/bad-foreign-blob.t
+++ b/test/bad-foreign-blob.t
@@ -17,6 +17,6 @@
   > EOF
 
   $ forester build
-  error: Failed to parse foreign blob $TESTCASE_ROOT/bad: expected JSON text (JSON value)
+  error[foreign]: Failed to parse foreign blob $TESTCASE_ROOT/bad: expected JSON text (JSON value)
       = Make sure the blob was generated with the version of forester that you are using.
   [1]
diff --git a/test/broken-link-gets-reported-only-once.t b/test/broken-link-gets-reported-only-once.t
index 7d00773..5b0b39c 100644
--- a/test/broken-link-gets-reported-only-once.t
+++ b/test/broken-link-gets-reported-only-once.t
@@ -17,7 +17,7 @@
   > EOF
 
   $ forester build > /dev/null
-  warning: Broken link https://www.my-great-forest.net/link/
-      ┌─ $TESTCASE_ROOT/trees/foo.tree:1:4
+  warning[broken_link]: Broken link https://www.my-great-forest.net/link/
+      ┌─ $TESTCASE_ROOT/trees/foo.tree:1:13
     1 │  \p{[broken](link)}
-      │     ^^^^^^^^^^^^^^ This tree was not found
+      │              ^^^^ This tree was not found
diff --git a/test/eval-errors.t b/test/eval-errors.t
index 23b1cc1..3621688 100644
--- a/test/eval-errors.t
+++ b/test/eval-errors.t
@@ -19,13 +19,13 @@
     2 │  \p{\hello}
       │    ^^^^^^^^ This is a function. Did you forget to provide some arguments?
       = expected some content
-  error: Invalid date
+  error[invalid_date]: Failed to parse date
       ┌─ $TESTCASE_ROOT/trees/invalid-date.tree:1:6
     1 │  \date{asdf}
-      │       ^^^^^^ 
-  error: unresolved identifier rel/has-taf
+      │       ^^^^^^ expected a date in the form of YYYY-MM-DD.
+  error[eval_error]: unresolved identifier rel/has-taf
       ┌─ $TESTCASE_ROOT/trees/unresolved-ident.tree:1:5
     1 │  \p{\rel/has-taf}
       │      ^^^^^^^^^^^ 
-      = Did you mean rel/has-tag?
+      = Did you mean \rel/has-tag?
   [1]
diff --git a/test/link-errors.t b/test/link-errors.t
index feb4b12..db30463 100644
--- a/test/link-errors.t
+++ b/test/link-errors.t
@@ -18,11 +18,12 @@
 
 
   $ forester build > /dev/null
-  warning: Broken link https://www.my-great-forest.net/foo/
-      ┌─ $TESTCASE_ROOT/trees/broken-link.tree:1:4
+  warning[broken_link]: Broken link https://www.my-great-forest.net/foo/
+      ┌─ $TESTCASE_ROOT/trees/broken-link.tree:1:28
     1 │  \p{[I am pointing nowhere](foo)}
-      │     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This tree was not found
-  error: Unlinked attribution
+      │                             ^^^ This tree was not found
+  warning[unlinked_attribution]: Did you mean \author/literal{unknown}?
       ┌─ $TESTCASE_ROOT/trees/unlinked-attribution.tree:1:8
     1 │  \author{unknown}
-      │         ^^^^^^^^^ Expected valid URI in attribution. Use `\author/literal` instead if you intend an unlinked attribution.
+      │         ^^^^^^^^^ Expected valid URI in attribution. Use `\author/literal{unknown}` instead if you intend an unlinked attribution.
+      = If there is a tree trees/unknown.tree, you may use the shorthand unknown instead of a full URI.
diff --git a/test/missing-import.t b/test/missing-import.t
index 220b133..484318a 100644
--- a/test/missing-import.t
+++ b/test/missing-import.t
@@ -4,8 +4,9 @@
   > \import{foo}
   > EOF
   $ forester build
-  error: Unresolved import
-      ┌─ $TESTCASE_ROOT/trees/index.tree:1:2
+  error[unresolved_import]: 
+      ┌─ $TESTCASE_ROOT/trees/index.tree:1:9
     1 │  \import{foo}
-      │   ^^^^^^^^^^^ No file foo.tree found.
+      │          ^^^ No file foo.tree found.
+      = checked the following directories: trees
   [1]
diff --git a/test/unlinked-attribution.t b/test/unlinked-attribution.t
index f6edf70..cb45d63 100644
--- a/test/unlinked-attribution.t
+++ b/test/unlinked-attribution.t
@@ -5,7 +5,8 @@
   > EOF
 
   $ forester build > /dev/null
-  error: Unlinked attribution
+  warning[unlinked_attribution]: Did you mean \author/literal{Kento}?
       ┌─ $TESTCASE_ROOT/trees/index.tree:1:8
     1 │  \author{Kento}
-      │         ^^^^^^^ Expected valid URI in attribution. Use `\author/literal` instead if you intend an unlinked attribution.
+      │         ^^^^^^^ Expected valid URI in attribution. Use `\author/literal{Kento}` instead if you intend an unlinked attribution.
+      = If there is a tree trees/Kento.tree, you may use the shorthand Kento instead of a full URI.
diff --git a/test/xml-errors.t b/test/xml-errors.t
index 24a2317..4f78057 100644
--- a/test/xml-errors.t
+++ b/test/xml-errors.t
@@ -7,7 +7,7 @@
   > EOF
 
   $ forester build
-  error: Unresolved XML namespace
+  error[expand_error]: Unresolved XML namespace
       ┌─ $TESTCASE_ROOT/trees/index.tree:2:4
     2 │    \<foo:bar>
       │     ^^^^^^^^^