diff --git a/common/chat-auto-parser-helpers.h b/common/chat-auto-parser-helpers.h
index 53d3454566..47e7a2a3d8 100644
--- a/common/chat-auto-parser-helpers.h
+++ b/common/chat-auto-parser-helpers.h
@@ -10,16 +10,47 @@ std::string trim_trailing_newlines(const std::string & str);
 
 // calculate a diff split (longest common prefix, longest common suffix excluding prefix,
 // mismatched part on the left, mismatched part on the right) between two strings
+// account for markers - align prefix and suffix endings so that they end on markers
+// * eg.:
+// calculate_diff_split("<html><body><div></div></body></html>", "<html><body><p>Something</p></body><html>") ->
+//  { "prefix": "<html><body>" (not: "<html><body><"), "suffix": "</body></html>", "left": "<div></div>", "right": "<p>Something</p>" }
+// calculate_diff_split("<html><body>Something</body></html>", "<html><body></body><html>") ->
+//  { "prefix": "<html><body>", "suffix": "</body></html>", "left": "Something", "right": "" }
 diff_split calculate_diff_split(const std::string & left, const std::string & right);
 
 // Returns the prefix of `full` up until the first occurrence of the common prefix of `left` and `right`
+// Returns empty string if there's no common prefix
+// * eg.:
+// until_common_prefix("really want a FUNCTION call", "FUNCTION alpha", "FUNCTION beta") -> "really want a "
+// until_common_prefix("<tool_call>", "<something>", "<something_else>") -> ""
+// until_common_prefix("some text", "1234", "abcd") -> ""
+// until_common_prefix("one arg two args three args four", "argument alpha", "argument beta") -> "one ""
 std::string until_common_prefix(const std::string & full, const std::string & left, const std::string & right);
 
 // Returns the suffix of `full` after the last occurrence of the common suffix of `left` and `right`
+// Returns empty string if there's no common suffix
+// Mirror function of `until_common_prefix`
+// * eg.:
+// after_common_suffix("really want a FUNCTION call", "first FUNCTION", "second FUNCTION") -> " call"
+// after_common_suffix("one arg two-args three args four", "alpha-args", "beta-args") -> " three args four"
 std::string after_common_suffix(const std::string & full, const std::string & left, const std::string & right);
 
 // Segmentize text into markers and non-marker fragments
+// * eg.:
+// segmentize_markers("<html><head><title>The site title</title><body><div>Here's some <b>content</b></div></body></html>" ->
+//  [ (MARKER, "<html>"), (MARKER, "<head>"), (MARKER, "<title>"), (TEXT, "The site title"), (MARKER, "</title>"),
+//    (MARKER, "<body>"), (MARKER, "<div>"), (TEXT, "Here's some "), (MARKER, "<b>"), (TEXT, "content"), (MARKER, "</b>"),
+//    (MARKER, "</div>"), (MARKER, "</body>"), (MARKER, "</html>")
+//  ]
+// segmentize_markers("<|tool_call|>[args]{ are here }[/args]<|tool_call_end|>") ->
+//  [ (MARKER, "<|tool_call|>"), (MARKER, "[args]"), (TEXT, "{ are here }"), (MARKER, "[/args]"), (MARKER, "<|tool_call_end|>") ]
 std::vector<segment> segmentize_markers(const std::string & text);
 
 // Prune whitespace-only segments from a vector of segments
+// * eg.:
+// segmentize_markers("<tool_call>\n<function=foo>\n<arg=bar>\n   \n</arg>\n</function>\n</tool_call>") ->
+//  X = [ (MARKER, "<tool_call>"), (TEXT, "\n"), (MARKER, "<function=foo>"), (TEXT, "\n"), (MARKER, "<arg=bar>"), (TEXT, "\n   \n"),
+//        (MARKER, "</arg>"), (TEXT, "\n"), (MARKER, "</function>"), (TEXT, "\n"), (MARKER, "</tool_call>") ]
+// prune_whitespace_segments(X) -> [ (MARKER, "<tool_call>"), (MARKER, "<function=foo>"), (MARKER, "<arg=bar>"), (MARKER, "</arg>"),
+//                                   (MARKER, "</function>"), (MARKER, "</tool_call>") ]
 std::vector<segment> prune_whitespace_segments(const std::vector<segment> & segments);
