diff --git a/content/pages/docs/kcl-lang/arithmetic.md b/content/pages/docs/kcl-lang/arithmetic.md
index be5898b1..15c37802 100644
--- a/content/pages/docs/kcl-lang/arithmetic.md
+++ b/content/pages/docs/kcl-lang/arithmetic.md
@@ -18,7 +18,9 @@ KCL supports the usual arithmetic operators on numbers and logic operators on bo
 | `\|` | Logical 'or' |
 | `!` | Unary logical 'not' |
 
-KCL also supports comparsion operators which operate on numbers and produce booleans:
+KCL also supports comparison operators which produce booleans. Ordering
+comparisons operate on numbers, while `==` and `!=` operate on numbers or
+strings:
 
 | Operator | Meaning |
 |----------|---------|
@@ -29,6 +31,9 @@ KCL also supports comparsion operators which operate on numbers and produce bool
 | `<=` | Less than or equal |
 | `>=` | Greater than or equal |
 
+String equality is exact and case-sensitive. It does not perform Unicode
+normalization.
+
 Arithmetics and logic expressions can be arbitrairly combined with the usual rules of associativity and precedence, e.g.,
 
 ```
diff --git a/content/pages/docs/kcl-lang/settings/project.md b/content/pages/docs/kcl-lang/settings/project.md
index 1a316b33..3743c826 100644
--- a/content/pages/docs/kcl-lang/settings/project.md
+++ b/content/pages/docs/kcl-lang/settings/project.md
@@ -27,31 +27,36 @@ base_unit = "in"
 
 ## Available Settings
 
-### cloud
+### settings
 
 
 
+#### meta
 
-### settings
+Information about the project itself. Choices about how settings are merged have prevent me (lee) from easily moving this out of the settings structure.
 
 
+**Default:** None
+
+This setting has the following nested options:
+
+##### id
 
-#### app
 
-The settings for the Design Studio.
 
 
 **Default:** None
 
-This setting has the following nested options:
 
-##### named_views
+#### app
 
-Settings that affect the behavior of the command bar.
+The settings for the Design Studio.
 
 
 **Default:** None
 
+This setting has the following nested options:
+
 ##### stream_idle_mode
 
 When the user is idle, and this is true, the stream will be torn down.
@@ -66,19 +71,9 @@ Zookeeper reasoning mode. Uses the app default if not set.
 
 **Default:** None
 
+##### named_views
 
-#### meta
-
-Information about the project itself. Choices about how settings are merged have prevent me (lee) from easily moving this out of the settings structure.
-
-
-**Default:** None
-
-This setting has the following nested options:
-
-##### id
-
-
+Settings that affect the behavior of the command bar.
 
 
 **Default:** None
@@ -98,6 +93,13 @@ This setting has the following nested options:
 The default unit to use in modeling dimensions.
 
 
+**Default:** None
+
+##### highlight_edges
+
+Highlight edges of 3D objects?
+
+
 **Default:** None
 
 ##### enable_ssao
@@ -114,12 +116,10 @@ When enabled, the grid will use a fixed size based on your selected units rather
 
 **Default:** None
 
-##### highlight_edges
 
-Highlight edges of 3D objects?
 
+### cloud
 
-**Default:** None
 
 
 
diff --git a/content/pages/docs/kcl-lang/settings/user.md b/content/pages/docs/kcl-lang/settings/user.md
index 9e905920..485eb7ae 100644
--- a/content/pages/docs/kcl-lang/settings/user.md
+++ b/content/pages/docs/kcl-lang/settings/user.md
@@ -63,16 +63,16 @@ Settings that affect the behavior while modeling.
 
 This setting has the following nested options:
 
-##### backface_color
+##### base_unit
 
-The default color to use for surface backfaces.
+The default unit to use in modeling dimensions. If not given, defaults to millimeters.
 
 
 **Default:** None
 
-##### base_unit
+##### camera_projection
 
-The default unit to use in modeling dimensions. If not given, defaults to millimeters.
+The projection mode the camera should use while modeling.
 
 
 **Default:** None
@@ -84,9 +84,9 @@ The methodology the camera should use to orbit around the model.
 
 **Default:** None
 
-##### camera_projection
+##### highlight_edges
 
-The projection mode the camera should use while modeling.
+Highlight edges of 3D objects?
 
 
 **Default:** None
@@ -98,23 +98,23 @@ Whether or not Screen Space Ambient Occlusion (SSAO) is enabled.
 
 **Default:** None
 
-##### fixed_size_grid
+##### backface_color
 
-When enabled, the grid will use a fixed size based on your selected units rather than automatically scaling with zoom level. If true, the grid cells will be fixed-size, where the width is your default length unit. If false, the grid will get larger as you zoom out, and smaller as you zoom in.
+The default color to use for surface backfaces.
 
 
 **Default:** None
 
-##### highlight_edges
+##### show_scale_grid
 
-Highlight edges of 3D objects?
+Whether or not to show a scale grid in the 3D modeling view
 
 
 **Default:** None
 
-##### show_scale_grid
+##### fixed_size_grid
 
-Whether or not to show a scale grid in the 3D modeling view
+When enabled, the grid will use a fixed size based on your selected units rather than automatically scaling with zoom level. If true, the grid cells will be fixed-size, where the width is your default length unit. If false, the grid will get larger as you zoom out, and smaller as you zoom in.
 
 
 **Default:** None
diff --git a/content/pages/docs/kcl-samples/manifest.json b/content/pages/docs/kcl-samples/manifest.json
index 63de0c8e..a918d63d 100644
--- a/content/pages/docs/kcl-samples/manifest.json
+++ b/content/pages/docs/kcl-samples/manifest.json
@@ -1110,8 +1110,7 @@
   {
     "file": "main.kcl",
     "categories": [
-      "Maker",
-      "Automotive"
+      "Maker"
     ],
     "pathFromProjectDirectoryToFirstFile": "stylized-car/main.kcl",
     "multipleFiles": false,
@@ -1124,7 +1123,6 @@
   {
     "file": "main.kcl",
     "categories": [
-      "Automotive",
       "Maker"
     ],
     "pathFromProjectDirectoryToFirstFile": "stylized-cybertruck/main.kcl",
@@ -1138,7 +1136,6 @@
   {
     "file": "main.kcl",
     "categories": [
-      "Automotive",
       "Maker"
     ],
     "pathFromProjectDirectoryToFirstFile": "stylized-dump-truck/main.kcl",
@@ -1152,7 +1149,6 @@
   {
     "file": "main.kcl",
     "categories": [
-      "Automotive",
       "Maker"
     ],
     "pathFromProjectDirectoryToFirstFile": "stylized-firetruck/main.kcl",
@@ -1166,7 +1162,6 @@
   {
     "file": "main.kcl",
     "categories": [
-      "Automotive",
       "Maker"
     ],
     "pathFromProjectDirectoryToFirstFile": "stylized-mini-bus/main.kcl",
@@ -1180,7 +1175,6 @@
   {
     "file": "main.kcl",
     "categories": [
-      "Automotive",
       "Maker"
     ],
     "pathFromProjectDirectoryToFirstFile": "stylized-pickup-truck/main.kcl",
diff --git a/content/pages/docs/kcl-samples/stylized-car/main.kcl b/content/pages/docs/kcl-samples/stylized-car/main.kcl
index 1b70abd2..39dd2096 100644
--- a/content/pages/docs/kcl-samples/stylized-car/main.kcl
+++ b/content/pages/docs/kcl-samples/stylized-car/main.kcl
@@ -1,6 +1,6 @@
 // Stylized Toy Car
 // A simplified, parametric 3-D model of a small toy car intended for use as a low-poly prop in real-time engines, visualization scenes, or rapid prototyping.
-// Categories: Maker, Automotive
+// Categories: Maker
 
 // The model includes:
 // - A chassis block forming the vehicle’s base
diff --git a/content/pages/docs/kcl-samples/stylized-cybertruck/main.kcl b/content/pages/docs/kcl-samples/stylized-cybertruck/main.kcl
index 7b02de81..6fc4079e 100644
--- a/content/pages/docs/kcl-samples/stylized-cybertruck/main.kcl
+++ b/content/pages/docs/kcl-samples/stylized-cybertruck/main.kcl
@@ -1,6 +1,6 @@
 // Stylized Toy Cybertruck
 // A simplified, parametric 3-D model of a low-poly toy cybertruck, intended for use as a game-ready asset, concept visualization, or real-time rendering demo.
-// Categories: Automotive, Maker
+// Categories: Maker
 
 // The model includes:
 // - A chassis block forming the vehicle’s base
diff --git a/content/pages/docs/kcl-samples/stylized-dump-truck/main.kcl b/content/pages/docs/kcl-samples/stylized-dump-truck/main.kcl
index 0d97c3b9..12144e33 100644
--- a/content/pages/docs/kcl-samples/stylized-dump-truck/main.kcl
+++ b/content/pages/docs/kcl-samples/stylized-dump-truck/main.kcl
@@ -1,6 +1,6 @@
 // Stylized Toy Dump Truck
 // A simplified, parametric 3D toy dump truck with front cab, extended cargo bed, and four wheels.
-// Categories: Automotive, Maker
+// Categories: Maker
 
 // The model includes:
 // - A chassis block forming the base
diff --git a/content/pages/docs/kcl-samples/stylized-firetruck/main.kcl b/content/pages/docs/kcl-samples/stylized-firetruck/main.kcl
index ed7e36ae..e32c5fb8 100644
--- a/content/pages/docs/kcl-samples/stylized-firetruck/main.kcl
+++ b/content/pages/docs/kcl-samples/stylized-firetruck/main.kcl
@@ -1,6 +1,6 @@
 // Stylized Toy Fire Truck
 // A toy parametric fire truck with extended rear compartment and roof ladder. Optimized for real-time rendering or schematic use in stylized design scenes.
-// Categories: Automotive, Maker
+// Categories: Maker
 
 // Set units and version
 @settings(defaultLengthUnit = m)
diff --git a/content/pages/docs/kcl-samples/stylized-mini-bus/main.kcl b/content/pages/docs/kcl-samples/stylized-mini-bus/main.kcl
index 4bfa9d04..9cfad2f4 100644
--- a/content/pages/docs/kcl-samples/stylized-mini-bus/main.kcl
+++ b/content/pages/docs/kcl-samples/stylized-mini-bus/main.kcl
@@ -1,6 +1,6 @@
 // Stylized Toy Mini-Bus
 // A simplified, parametric 3-D model of a toy compact van or mini-bus, intended for use as a low-poly prop in real-time engines, visualization scenes, or rapid prototyping.
-// Categories: Automotive, Maker
+// Categories: Maker
 
 // The model includes:
 // - A solid chassis block forming the vehicle’s base
diff --git a/content/pages/docs/kcl-samples/stylized-pickup-truck/main.kcl b/content/pages/docs/kcl-samples/stylized-pickup-truck/main.kcl
index 7048801c..6fb90774 100644
--- a/content/pages/docs/kcl-samples/stylized-pickup-truck/main.kcl
+++ b/content/pages/docs/kcl-samples/stylized-pickup-truck/main.kcl
@@ -1,6 +1,6 @@
 // Stylized Toy Pickup Truck
 // A simplified, parametric 3-D model of a toy pickup truck intended for use as a low-poly prop in real-time engines, visualization scenes, or rapid prototyping.
-// Categories: Automotive, Maker
+// Categories: Maker
 
 // The model includes:
 // - A chassis block forming the vehicle’s base
diff --git a/content/pages/docs/kcl-std/functions/std-fail.md b/content/pages/docs/kcl-std/functions/std-fail.md
new file mode 100644
index 00000000..59abcaf0
--- /dev/null
+++ b/content/pages/docs/kcl-std/functions/std-fail.md
@@ -0,0 +1,45 @@
+---
+title: "fail"
+subtitle: "Function in std"
+excerpt: "Stop KCL evaluation with a user-defined error."
+layout: manual
+---
+
+**WARNING:** This function is experimental and may change or be removed.
+
+Stop KCL evaluation with a user-defined error.
+
+```kcl
+fail(@msg: string): never
+```
+
+Use `fail` when evaluation cannot continue and the caller should receive a
+specific error message. `fail` never returns a value.
+
+### Arguments
+
+| Name | Type | Description | Required |
+|----------|------|-------------|----------|
+| `msg` | [`string`](/docs/kcl-std/types/std-types-string) | Message reported to the caller. | Yes |
+
+### Returns
+
+[`never`](/docs/kcl-std/types/std-types-never) - The uninhabited type of computations that never complete normally.
+
+
+### Examples
+
+```kcl
+fn positive(@value: number): number {
+  return if value > 0 {
+    value
+  } else {
+    fail("value must be positive")
+  }
+}
+
+```
+
+
+
+
diff --git a/content/pages/docs/kcl-std/functions/std-runtime-exit.md b/content/pages/docs/kcl-std/functions/std-runtime-exit.md
index c3288a5d..ca7b6999 100644
--- a/content/pages/docs/kcl-std/functions/std-runtime-exit.md
+++ b/content/pages/docs/kcl-std/functions/std-runtime-exit.md
@@ -13,7 +13,16 @@ Exit the program early.
 exit()
 ```
 
+Exiting early can be helpful to see the intermediate output of a program to
+help debug. Remember to always remove the call to `exit()` after debugging
+is complete.
 
+When `exit()` is used in an imported module, only the imported module exits
+early. Because imported modules execute concurrently, `exit()` in one module
+does not affect other modules.
+
+On the other hand, if you import a function from another module, and that
+function calls `exit()`, then calling the function exits the caller.
 
 
 
diff --git a/content/pages/docs/kcl-std/functions/std-sketch-extrude.md b/content/pages/docs/kcl-std/functions/std-sketch-extrude.md
index a98022c8..1c6d0de7 100644
--- a/content/pages/docs/kcl-std/functions/std-sketch-extrude.md
+++ b/content/pages/docs/kcl-std/functions/std-sketch-extrude.md
@@ -9,11 +9,11 @@ Extend a 2-dimensional sketch or individual segment of a sketch through a third
 
 ```kcl
 extrude(
-  @sketches: [Sketch | Face | TaggedFace | TaggedEdge | Edge | Segment; 1+],
+  @sketches: [Sketch | Face | TaggedFace | TaggedEdge | Edge | Segment | any; 1+],
   length?: number(Length),
   to?: Point3d | Axis3d | Plane | Edge | Face | Sketch | Solid | TaggedEdge | TaggedFace | any,
   symmetric?: bool,
-  direction?: Point3d | Edge | TaggedEdge | Segment,
+  direction?: Point3d | Edge | TaggedEdge | Segment | any,
   bidirectionalLength?: number(Length),
   tagStart?: TagDecl,
   tagEnd?: TagDecl,
@@ -39,11 +39,11 @@ can change this behavior by using the `method` parameter. See
 
 | Name | Type | Description | Required |
 |----------|------|-------------|----------|
-| `sketches` | [[`Sketch`](/docs/kcl-std/types/std-types-Sketch) or [`Face`](/docs/kcl-std/types/std-types-Face) or [`TaggedFace`](/docs/kcl-std/types/std-types-TaggedFace) or [`TaggedEdge`](/docs/kcl-std/types/std-types-TaggedEdge) or [`Edge`](/docs/kcl-std/types/std-types-Edge) or [`Segment`](/docs/kcl-std/types/std-types-Segment); 1+] | Which sketch or sketches should be extruded. | Yes |
+| `sketches` | [[`Sketch`](/docs/kcl-std/types/std-types-Sketch) or [`Face`](/docs/kcl-std/types/std-types-Face) or [`TaggedFace`](/docs/kcl-std/types/std-types-TaggedFace) or [`TaggedEdge`](/docs/kcl-std/types/std-types-TaggedEdge) or [`Edge`](/docs/kcl-std/types/std-types-Edge) or [`Segment`](/docs/kcl-std/types/std-types-Segment) or [`any`](/docs/kcl-std/types/std-types-any); 1+] | Which sketch or sketches should be extruded. Experimental face API: edge specifier objects (`{ sideFaces = [faceTag1, faceTag2], endFaces? = [...], index? }`) are not ready for generated or user-facing KCL yet; prefer existing sketch, face, tagged face, tagged edge, edge, or segment forms until point-and-click and migration support ships. | Yes |
 | `length` | [`number(Length)`](/docs/kcl-std/types/std-types-number) | How far to extrude the given sketches. Incompatible with `to`. | No |
 | `to` | [`Point3d`](/docs/kcl-std/types/std-types-Point3d) or [`Axis3d`](/docs/kcl-std/types/std-types-Axis3d) or [`Plane`](/docs/kcl-std/types/std-types-Plane) or [`Edge`](/docs/kcl-std/types/std-types-Edge) or [`Face`](/docs/kcl-std/types/std-types-Face) or [`Sketch`](/docs/kcl-std/types/std-types-Sketch) or [`Solid`](/docs/kcl-std/types/std-types-Solid) or [`TaggedEdge`](/docs/kcl-std/types/std-types-TaggedEdge) or [`TaggedFace`](/docs/kcl-std/types/std-types-TaggedFace) or [`any`](/docs/kcl-std/types/std-types-any) | Reference to extrude to. Incompatible with `length` and `twistAngle`. Experimental face API: edge specifier objects (`{ sideFaces = [faceTag1, faceTag2], endFaces? = [...], index? }`) are not ready for generated or user-facing KCL yet; prefer existing point, axis, plane, edge, face, sketch, solid, or tag forms until point-and-click and migration support ships. | No |
 | `symmetric` | [`bool`](/docs/kcl-std/types/std-types-bool) | If true, the extrusion will happen symmetrically around the sketch. Otherwise, the extrusion will happen on only one side of the sketch. | No |
-| `direction` | [`Point3d`](/docs/kcl-std/types/std-types-Point3d) or [`Edge`](/docs/kcl-std/types/std-types-Edge) or [`TaggedEdge`](/docs/kcl-std/types/std-types-TaggedEdge) or [`Segment`](/docs/kcl-std/types/std-types-Segment) | If specified, will extrude in this direction instead of the sketch plane normal. If an edge is being extruded, this defaults to halfway between the faces on either side of the edge. | No |
+| `direction` | [`Point3d`](/docs/kcl-std/types/std-types-Point3d) or [`Edge`](/docs/kcl-std/types/std-types-Edge) or [`TaggedEdge`](/docs/kcl-std/types/std-types-TaggedEdge) or [`Segment`](/docs/kcl-std/types/std-types-Segment) or [`any`](/docs/kcl-std/types/std-types-any) | If specified, will extrude in this direction instead of the sketch plane normal. If an edge is being extruded, this defaults to halfway between the faces on either side of the edge. | No |
 | `bidirectionalLength` | [`number(Length)`](/docs/kcl-std/types/std-types-number) | If specified, will also extrude in the opposite direction to 'distance' to the specified distance. If 'symmetric' is true, this value is ignored. | No |
 | `tagStart` | [`TagDecl`](/docs/kcl-std/types/std-types-TagDecl) | A named tag for the face at the start of the extrusion, i.e. the original sketch. | No |
 | `tagEnd` | [`TagDecl`](/docs/kcl-std/types/std-types-TagDecl) | A named tag for the face at the end of the extrusion, i.e. the new face created by extruding the original sketch. | No |
@@ -766,3 +766,5 @@ extrude002 = extrude(
   touch-action="pan-y"
 >
 </model-viewer>
+
+
diff --git a/content/pages/docs/kcl-std/functions/std-string-isEqual.md b/content/pages/docs/kcl-std/functions/std-string-isEqual.md
new file mode 100644
index 00000000..d45c6d40
--- /dev/null
+++ b/content/pages/docs/kcl-std/functions/std-string-isEqual.md
@@ -0,0 +1,58 @@
+---
+title: "string::isEqual"
+subtitle: "Function in std::string"
+excerpt: "Compare two strings for equality."
+layout: manual
+---
+
+Compare two strings for equality.
+
+```kcl
+string::isEqual(
+  @text: string,
+  to: string,
+  caseInsensitive?: bool,
+): bool
+```
+
+By default, this performs an exact, case-sensitive comparison equivalent
+to the `==` operator. Set `caseInsensitive` to `true` to compare using
+locale-independent full Unicode case folding.
+
+Full case folding may expand characters; for example, `Straße` and
+`STRASSE` compare as equal. The exact mappings follow the Unicode data
+bundled with KCL.
+
+Unicode normalization is not performed. Canonically equivalent strings
+with different representations therefore compare as unequal. Empty strings
+are valid inputs, and comparison is symmetric.
+
+This function always returns a Boolean predicate, including inside a sketch
+block. It does not create an equivalence constraint.
+
+### Arguments
+
+| Name | Type | Description | Required |
+|----------|------|-------------|----------|
+| `text` | [`string`](/docs/kcl-std/types/std-types-string) | The string to compare. | Yes |
+| `to` | [`string`](/docs/kcl-std/types/std-types-string) | The string to compare `text` with. | Yes |
+| `caseInsensitive` | [`bool`](/docs/kcl-std/types/std-types-bool) | Whether to compare using locale-independent full Unicode case folding. | No |
+
+### Returns
+
+[`bool`](/docs/kcl-std/types/std-types-bool) - A boolean value.
+
+
+### Examples
+
+```kcl
+matches = "Straße"
+  |> string::isEqual(to = "STRASSE", caseInsensitive = true)
+
+assertIs(matches)
+
+```
+
+
+
+
diff --git a/content/pages/docs/kcl-std/functions/std-string-lowercase.md b/content/pages/docs/kcl-std/functions/std-string-lowercase.md
new file mode 100644
index 00000000..f0ef5dba
--- /dev/null
+++ b/content/pages/docs/kcl-std/functions/std-string-lowercase.md
@@ -0,0 +1,48 @@
+---
+title: "string::lowercase"
+subtitle: "Function in std::string"
+excerpt: "Convert all cased characters in a string to lowercase."
+layout: manual
+---
+
+Convert all cased characters in a string to lowercase.
+
+```kcl
+string::lowercase(@text: string): string
+```
+
+This conversion is Unicode-aware and locale-independent. Some conversions
+depend on the surrounding characters; for example, a Greek capital sigma
+becomes `ς` at the end of a word and `σ` elsewhere. Some characters expand
+into multiple characters; for example, `İ` becomes `i` followed by a
+combining dot above. The exact mappings follow the Unicode data bundled
+with KCL.
+
+Unicode normalization is not performed. Canonically equivalent strings
+therefore retain their original representations. Empty strings and strings
+without cased characters are returned unchanged.
+
+### Arguments
+
+| Name | Type | Description | Required |
+|----------|------|-------------|----------|
+| `text` | [`string`](/docs/kcl-std/types/std-types-string) | The string to convert. | Yes |
+
+### Returns
+
+[`string`](/docs/kcl-std/types/std-types-string) - A sequence of characters
+
+
+### Examples
+
+```kcl
+result = "KCL ΟΣ"
+  |> string::lowercase()
+
+assertIs(result == "kcl ος")
+
+```
+
+
+
+
diff --git a/content/pages/docs/kcl-std/functions/std-string-trim.md b/content/pages/docs/kcl-std/functions/std-string-trim.md
new file mode 100644
index 00000000..d738b2fb
--- /dev/null
+++ b/content/pages/docs/kcl-std/functions/std-string-trim.md
@@ -0,0 +1,44 @@
+---
+title: "string::trim"
+subtitle: "Function in std::string"
+excerpt: "Remove whitespace from the start and end of a string."
+layout: manual
+---
+
+Remove whitespace from the start and end of a string.
+
+```kcl
+string::trim(@text: string): string
+```
+
+Whitespace is defined by Unicode's `White_Space` property and includes
+spaces, tabs, newlines, and non-breaking spaces. Whitespace inside the
+string is preserved.
+
+If the input is empty or contains only whitespace, this returns an empty
+string. Unicode normalization and case conversion are not performed.
+
+### Arguments
+
+| Name | Type | Description | Required |
+|----------|------|-------------|----------|
+| `text` | [`string`](/docs/kcl-std/types/std-types-string) | The string to trim. | Yes |
+
+### Returns
+
+[`string`](/docs/kcl-std/types/std-types-string) - A sequence of characters
+
+
+### Examples
+
+```kcl
+result = "  KCL strings  "
+  |> string::trim()
+
+assertIs(result == "KCL strings")
+
+```
+
+
+
+
diff --git a/content/pages/docs/kcl-std/functions/std-string-trimEnd.md b/content/pages/docs/kcl-std/functions/std-string-trimEnd.md
new file mode 100644
index 00000000..768b1c09
--- /dev/null
+++ b/content/pages/docs/kcl-std/functions/std-string-trimEnd.md
@@ -0,0 +1,47 @@
+---
+title: "string::trimEnd"
+subtitle: "Function in std::string"
+excerpt: "Remove whitespace from the end of a string."
+layout: manual
+---
+
+Remove whitespace from the end of a string.
+
+```kcl
+string::trimEnd(@text: string): string
+```
+
+Whitespace is defined by Unicode's `White_Space` property and includes
+spaces, tabs, newlines, and non-breaking spaces. Only the contiguous
+whitespace at the end is removed; whitespace at the start or inside the
+string is preserved.
+
+The end is the end of the string's character sequence, independent of how
+the text is displayed. If the input is empty or contains only whitespace,
+this returns an empty string. Unicode normalization and case conversion are
+not performed.
+
+### Arguments
+
+| Name | Type | Description | Required |
+|----------|------|-------------|----------|
+| `text` | [`string`](/docs/kcl-std/types/std-types-string) | The string to trim. | Yes |
+
+### Returns
+
+[`string`](/docs/kcl-std/types/std-types-string) - A sequence of characters
+
+
+### Examples
+
+```kcl
+result = "  KCL strings  "
+  |> string::trimEnd()
+
+assertIs(result == "  KCL strings")
+
+```
+
+
+
+
diff --git a/content/pages/docs/kcl-std/functions/std-string-trimStart.md b/content/pages/docs/kcl-std/functions/std-string-trimStart.md
new file mode 100644
index 00000000..c600cea8
--- /dev/null
+++ b/content/pages/docs/kcl-std/functions/std-string-trimStart.md
@@ -0,0 +1,47 @@
+---
+title: "string::trimStart"
+subtitle: "Function in std::string"
+excerpt: "Remove whitespace from the start of a string."
+layout: manual
+---
+
+Remove whitespace from the start of a string.
+
+```kcl
+string::trimStart(@text: string): string
+```
+
+Whitespace is defined by Unicode's `White_Space` property and includes
+spaces, tabs, newlines, and non-breaking spaces. Only the contiguous
+whitespace at the start is removed; whitespace inside or at the end of the
+string is preserved.
+
+The start is the beginning of the string's character sequence, independent
+of how the text is displayed. If the input is empty or contains only
+whitespace, this returns an empty string. Unicode normalization and case
+conversion are not performed.
+
+### Arguments
+
+| Name | Type | Description | Required |
+|----------|------|-------------|----------|
+| `text` | [`string`](/docs/kcl-std/types/std-types-string) | The string to trim. | Yes |
+
+### Returns
+
+[`string`](/docs/kcl-std/types/std-types-string) - A sequence of characters
+
+
+### Examples
+
+```kcl
+result = "  KCL strings  "
+  |> string::trimStart()
+
+assertIs(result == "KCL strings  ")
+
+```
+
+
+
+
diff --git a/content/pages/docs/kcl-std/functions/std-string-uppercase.md b/content/pages/docs/kcl-std/functions/std-string-uppercase.md
new file mode 100644
index 00000000..376b3da7
--- /dev/null
+++ b/content/pages/docs/kcl-std/functions/std-string-uppercase.md
@@ -0,0 +1,45 @@
+---
+title: "string::uppercase"
+subtitle: "Function in std::string"
+excerpt: "Convert all cased characters in a string to uppercase."
+layout: manual
+---
+
+Convert all cased characters in a string to uppercase.
+
+```kcl
+string::uppercase(@text: string): string
+```
+
+This conversion is Unicode-aware and locale-independent. Some characters
+expand into multiple characters; for example, `ß` becomes `SS`. The exact
+mappings follow the Unicode data bundled with KCL.
+
+Unicode normalization is not performed. Canonically equivalent strings
+therefore retain their original representations. Empty strings and strings
+without cased characters are returned unchanged.
+
+### Arguments
+
+| Name | Type | Description | Required |
+|----------|------|-------------|----------|
+| `text` | [`string`](/docs/kcl-std/types/std-types-string) | The string to convert. | Yes |
+
+### Returns
+
+[`string`](/docs/kcl-std/types/std-types-string) - A sequence of characters
+
+
+### Examples
+
+```kcl
+result = "Straße"
+  |> string::uppercase()
+
+assertIs(result == "STRASSE")
+
+```
+
+
+
+
diff --git a/content/pages/docs/kcl-std/functions/std-transform-mirror3d.md b/content/pages/docs/kcl-std/functions/std-transform-mirror3d.md
index c5615f3b..8ba16c32 100644
--- a/content/pages/docs/kcl-std/functions/std-transform-mirror3d.md
+++ b/content/pages/docs/kcl-std/functions/std-transform-mirror3d.md
@@ -10,7 +10,7 @@ Create a mirror image of a 3D solid/surface/body, across some specified mirror a
 ```kcl
 mirror3d(
   @bodies: [Solid; 1+],
-  across: Edge | Plane | Axis3d | Segment,
+  across: Edge | Plane | Axis3d | Segment | any,
 ): [Solid; 1+]
 ```
 
@@ -21,7 +21,7 @@ mirror3d(
 | Name | Type | Description | Required |
 |----------|------|-------------|----------|
 | `bodies` | [[`Solid`](/docs/kcl-std/types/std-types-Solid); 1+] | The body or bodies to be reflected. | Yes |
-| `across` | [`Edge`](/docs/kcl-std/types/std-types-Edge) or [`Plane`](/docs/kcl-std/types/std-types-Plane) or [`Axis3d`](/docs/kcl-std/types/std-types-Axis3d) or [`Segment`](/docs/kcl-std/types/std-types-Segment) | The axis (or other geometry) to reflect across. | Yes |
+| `across` | [`Edge`](/docs/kcl-std/types/std-types-Edge) or [`Plane`](/docs/kcl-std/types/std-types-Plane) or [`Axis3d`](/docs/kcl-std/types/std-types-Axis3d) or [`Segment`](/docs/kcl-std/types/std-types-Segment) or [`any`](/docs/kcl-std/types/std-types-any) | The axis (or other geometry) to reflect across. An edge specifier object such as `{ sideFaces = [faceTag1, faceTag2] }` can identify a solid edge without using its UUID. | Yes |
 
 ### Returns
 
diff --git a/content/pages/docs/kcl-std/index.md b/content/pages/docs/kcl-std/index.md
index b37e8810..f393d706 100644
--- a/content/pages/docs/kcl-std/index.md
+++ b/content/pages/docs/kcl-std/index.md
@@ -14,6 +14,7 @@ layout: manual
   * [`clone`](/docs/kcl-std/functions/std-clone)
   * [`edgeId`](/docs/kcl-std/functions/std-edgeId)
   * [`faceId`](/docs/kcl-std/functions/std-faceId)
+  * [`fail`](/docs/kcl-std/functions/std-fail) Experimental
   * [`helix`](/docs/kcl-std/functions/std-helix)
   * [`offsetPlane`](/docs/kcl-std/functions/std-offsetPlane)
 * [**std::appearance**](/docs/kcl-std/modules/std-appearance)
@@ -186,6 +187,13 @@ layout: manual
   * [`solver::tangent`](/docs/kcl-std/functions/std-solver-tangent)
   * [`solver::vertical`](/docs/kcl-std/functions/std-solver-vertical)
   * [`solver::verticalDistance`](/docs/kcl-std/functions/std-solver-verticalDistance)
+* [**std::string**](/docs/kcl-std/modules/std-string)
+  * [`string::isEqual`](/docs/kcl-std/functions/std-string-isEqual)
+  * [`string::lowercase`](/docs/kcl-std/functions/std-string-lowercase)
+  * [`string::trim`](/docs/kcl-std/functions/std-string-trim)
+  * [`string::trimEnd`](/docs/kcl-std/functions/std-string-trimEnd)
+  * [`string::trimStart`](/docs/kcl-std/functions/std-string-trimStart)
+  * [`string::uppercase`](/docs/kcl-std/functions/std-string-uppercase)
 * [**std::transform**](/docs/kcl-std/modules/std-transform)
   * [`delete`](/docs/kcl-std/functions/std-transform-delete) Experimental
   * [`hide`](/docs/kcl-std/functions/std-transform-hide)
@@ -255,6 +263,7 @@ See also the [types overview](/docs/kcl-lang/types)
   * [`any`](/docs/kcl-std/types/std-types-any)
   * [`bool`](/docs/kcl-std/types/std-types-bool)
   * [`fn`](/docs/kcl-std/types/std-types-fn)
+  * [`never`](/docs/kcl-std/types/std-types-never) Experimental
   * [`none`](/docs/kcl-std/types/std-types-none) Experimental
   * [`number`](/docs/kcl-std/types/std-types-number)
   * [`string`](/docs/kcl-std/types/std-types-string)
diff --git a/content/pages/docs/kcl-std/modules/std-string.md b/content/pages/docs/kcl-std/modules/std-string.md
new file mode 100644
index 00000000..65f02dd1
--- /dev/null
+++ b/content/pages/docs/kcl-std/modules/std-string.md
@@ -0,0 +1,23 @@
+---
+title: "string"
+subtitle: "Module in std"
+excerpt: "Operations on KCL strings. "
+layout: manual
+---
+
+Operations on KCL strings. 
+
+This module provides functions for transforming strings and inspecting
+their contents.
+
+
+
+## Functions and constants
+
+* [`string::isEqual`](/docs/kcl-std/functions/std-string-isEqual)
+* [`string::lowercase`](/docs/kcl-std/functions/std-string-lowercase)
+* [`string::trim`](/docs/kcl-std/functions/std-string-trim)
+* [`string::trimEnd`](/docs/kcl-std/functions/std-string-trimEnd)
+* [`string::trimStart`](/docs/kcl-std/functions/std-string-trimStart)
+* [`string::uppercase`](/docs/kcl-std/functions/std-string-uppercase)
+
diff --git a/content/pages/docs/kcl-std/modules/std-types.md b/content/pages/docs/kcl-std/modules/std-types.md
index 281bd5a4..8deca1d3 100644
--- a/content/pages/docs/kcl-std/modules/std-types.md
+++ b/content/pages/docs/kcl-std/modules/std-types.md
@@ -42,6 +42,7 @@ does.
 * [`in`](/docs/kcl-std/types/std-types-in)
 * [`m`](/docs/kcl-std/types/std-types-m)
 * [`mm`](/docs/kcl-std/types/std-types-mm)
+* [`never`](/docs/kcl-std/types/std-types-never)
 * [`none`](/docs/kcl-std/types/std-types-none)
 * [`number`](/docs/kcl-std/types/std-types-number)
 * [`rad`](/docs/kcl-std/types/std-types-rad)
diff --git a/content/pages/docs/kcl-std/modules/std.md b/content/pages/docs/kcl-std/modules/std.md
index f9b70f3d..6812c3c0 100644
--- a/content/pages/docs/kcl-std/modules/std.md
+++ b/content/pages/docs/kcl-std/modules/std.md
@@ -28,6 +28,7 @@ You might also want the [KCL language reference](/docs/kcl-lang) or the [KCL gui
 * [`sketch`](/docs/kcl-std/modules/std-sketch)
 * [`solid`](/docs/kcl-std/modules/std-solid)
 * [`solver`](/docs/kcl-std/modules/std-solver)
+* [`string::string`](/docs/kcl-std/modules/std-string)
 * [`sweep::sweep`](/docs/kcl-std/modules/std-sweep)
 * [`transform`](/docs/kcl-std/modules/std-transform)
 * [`turns::turns`](/docs/kcl-std/modules/std-turns)
@@ -56,6 +57,7 @@ You might also want the [KCL language reference](/docs/kcl-lang) or the [KCL gui
 * [`clone`](/docs/kcl-std/functions/std-clone)
 * [`edgeId`](/docs/kcl-std/functions/std-edgeId)
 * [`faceId`](/docs/kcl-std/functions/std-faceId)
+* [`fail`](/docs/kcl-std/functions/std-fail)
 * [`helix`](/docs/kcl-std/functions/std-helix)
 * [`offsetPlane`](/docs/kcl-std/functions/std-offsetPlane)
 
diff --git a/content/pages/docs/kcl-std/types/std-types-never.md b/content/pages/docs/kcl-std/types/std-types-never.md
new file mode 100644
index 00000000..6ce46339
--- /dev/null
+++ b/content/pages/docs/kcl-std/types/std-types-never.md
@@ -0,0 +1,18 @@
+---
+title: "never"
+subtitle: "Type in std::types"
+excerpt: "The uninhabited type of computations that never complete normally."
+layout: manual
+---
+
+**WARNING:** This type is experimental and may change or be removed.
+
+The uninhabited type of computations that never complete normally.
+
+[`never`](/docs/kcl-std/types/std-types-never) has no values and is a subtype of every type. Use it as the return
+type of a function that always stops evaluation by raising an error. A
+function declared to return [`never`](/docs/kcl-std/types/std-types-never) produces a type error if it returns a
+value or reaches the end of its body.
+
+
+