diff --git a/src/FSharp.Formatting.CodeFormat/CommentFilter.fs b/src/FSharp.Formatting.CodeFormat/CommentFilter.fs
index 171afd84..f71dcfa3 100644
--- a/src/FSharp.Formatting.CodeFormat/CommentFilter.fs
+++ b/src/FSharp.Formatting.CodeFormat/CommentFilter.fs
@@ -2,6 +2,9 @@
 // F# CodeFormat (CommentProcessing.fs)
 // (c) Tomas Petricek, 2012, Available under Apache 2.0 license.
 // --------------------------------------------------------------------------------------
+/// Internal module for pre-processing F# source snippets: extracting named snippet regions
+/// (<c>// [snippet:Name]</c> / <c>// [/snippet]</c>), shrinking omitted blocks
+/// (<c>(*[omit:...]*)..(*[/omit]*)</c>), and surfacing FSI output markers (<c>// [fsi:...]</c>).
 module internal FSharp.Formatting.CodeFormat.CommentFilter
 
 open System.Text
diff --git a/src/FSharp.Formatting.CodeFormat/LatexFormatting.fs b/src/FSharp.Formatting.CodeFormat/LatexFormatting.fs
index 44c314d3..c760cdd8 100644
--- a/src/FSharp.Formatting.CodeFormat/LatexFormatting.fs
+++ b/src/FSharp.Formatting.CodeFormat/LatexFormatting.fs
@@ -3,6 +3,7 @@
 // (c) Tomas Petricek, 2012, Available under Apache 2.0 license.
 // --------------------------------------------------------------------------------------
 
+/// Internal module for rendering F# code snippets as LaTeX using the lstlistings environment.
 module internal FSharp.Formatting.CodeFormat.Latex
 
 open System
@@ -28,6 +29,8 @@ let specialChars =
        "~", @"{\textasciitilde}"
        "^", @"{\textasciicircum}" |]
 
+/// Escape a string for safe inclusion in LaTeX source,
+/// substituting all LaTeX special characters with their command equivalents.
 let latexEncode s =
     specialChars
     |> Array.fold (fun (acc: string) (k, v) -> acc.Replace(k, v)) (HttpUtility.HtmlDecode s)
diff --git a/src/FSharp.Formatting.CodeFormat/SourceCode.fs b/src/FSharp.Formatting.CodeFormat/SourceCode.fs
index d8522adf..7d6d6a5b 100644
--- a/src/FSharp.Formatting.CodeFormat/SourceCode.fs
+++ b/src/FSharp.Formatting.CodeFormat/SourceCode.fs
@@ -82,8 +82,10 @@ type SourceError =
     /// error kind and the message
     | SourceError of start: (int * int) * finish: (int * int) * errorKind: ErrorKind * message: string
 
+/// Internal helpers for mapping TokenKind values to CSS class names.
 module internal CodeFormatHelper =
 
+    /// Map a TokenKind to the corresponding CSS class name string using the default CSS class map.
     let defaultTokenMap kind =
         match kind with
         | TokenKind.Comment -> CSS.Comment
diff --git a/src/FSharp.Formatting.Literate/ParseScript.fs b/src/FSharp.Formatting.Literate/ParseScript.fs
index 8873edd4..d5987ca1 100644
--- a/src/FSharp.Formatting.Literate/ParseScript.fs
+++ b/src/FSharp.Formatting.Literate/ParseScript.fs
@@ -36,6 +36,7 @@ module internal CodeBlockUtils =
             | _ -> false)
         |> List.ofSeq
 
+    /// Split a string into lines, normalising line endings.
     let splitLines (s: string) =
         s.Replace("\r\n", "\n").Split([| '\n' |])
 
@@ -149,15 +150,18 @@ open CodeBlockUtils
 /// as hide, define and include.
 type internal ParseScript(parseOptions, ctx: CompilerContext) =
 
+    /// Determine the visibility of a code block based on its commands dictionary.
     let getVisibility cmds =
         match cmds with
         | Command "hide" _ -> LiterateCodeVisibility.HiddenCode
         | Command "define" name -> LiterateCodeVisibility.NamedCode name
         | _ -> LiterateCodeVisibility.VisibleCode
 
+    /// Return true if a code block should be evaluated, based on global noEval flag and block commands.
     let getEvaluate noEval (cmds: IDictionary<_, _>) =
         not (noEval || cmds.ContainsKey("do-not-eval"))
 
+    /// Extract paragraph options (conditional defines) from block commands.
     let getParaOptions cmds =
         match cmds with
         | Command "condition" name when not (String.IsNullOrWhiteSpace name) -> { Condition = Some name }
diff --git a/src/FSharp.Formatting.Literate/Transformations.fs b/src/FSharp.Formatting.Literate/Transformations.fs
index 1546bbb2..cb998dc9 100644
--- a/src/FSharp.Formatting.Literate/Transformations.fs
+++ b/src/FSharp.Formatting.Literate/Transformations.fs
@@ -10,6 +10,9 @@ open FSharp.Formatting.CodeFormat
 open FSharp.Formatting.Literate.Evaluation
 open FSharp.Formatting.Markdown
 
+/// Internal transformations applied to a LiterateDocument:
+/// formatting F# code snippets, evaluating them with FSI, resolving references,
+/// and replacing literate paragraphs with their final HTML/LaTeX/Fsx representations.
 module internal Transformations =
     // ----------------------------------------------------------------------------------------------
     // Replace all code snippets (assume F#) with their nicely formatted versions
@@ -460,7 +463,8 @@ module internal Transformations =
           | _ -> () ]
 
 
-    /// Replace all special 'LiterateParagraph' elements recursively using the given lookup dictionary
+    /// Format a non-F# language-tagged code block as an HTML table with optional line numbers,
+    /// using the CSharpFormat syntax highlighter for the given language.
     let replaceHtmlTaggedCode (ctx: LiterateProcessingContext) (lang: string) (code: string) =
         let sb = new System.Text.StringBuilder()
         let writer = new System.IO.StringWriter(sb)