diff --git a/src/util/spanparsing.h b/src/util/spanparsing.h
index 130100ba9..4ecf033ff 100644
--- a/src/util/spanparsing.h
+++ b/src/util/spanparsing.h
@@ -1,31 +1,51 @@
 // Copyright (c) 2018 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_UTIL_SPANPARSING_H
 #define BITCOIN_UTIL_SPANPARSING_H
 
 #include <span.h>
 
 #include <string>
 #include <vector>
 
 namespace spanparsing {
 
-/** Parse a constant. If successful, sp is updated to skip the constant and
- * return true. */
+/** Parse a constant.
+ *
+ * If sp's initial part matches str, sp is updated to skip that part, and true
+ * is returned. Otherwise sp is unmodified and false is returned.
+ */
 bool Const(const std::string &str, Span<const char> &sp);
 
-/** Parse a function call. If successful, sp is updated to be the function's
- * argument(s). */
+/** Parse a function call.
+ *
+ * If sp's initial part matches str + "(", and sp ends with ")", sp is updated
+ * to be the section between the braces, and true is returned. Otherwise sp is
+ * unmodified and false is returned.
+ */
 bool Func(const std::string &str, Span<const char> &sp);
 
-/** Return the expression that sp begins with, and update sp to skip it. */
+/** Extract the expression that sp begins with.
+ *
+ * This function will return the initial part of sp, up to (but not including)
+ * the first comma or closing brace, skipping ones that are surrounded by
+ * braces. So for example, for "foo(bar(1),2),3" the initial part
+ * "foo(bar(1),2)" will be returned. sp will be updated to skip the initial part
+ * that is returned.
+ */
 Span<const char> Expr(Span<const char> &sp);
 
-/** Split a string on every instance of sep, returning a vector. */
+/** Split a string on every instance of sep, returning a vector.
+ *
+ * If sep does not occur in sp, a singleton with the entirety of sp is returned.
+ *
+ * Note that this function does not care about braces, so splitting
+ * "foo(bar(1),2),3) on ',' will return {"foo(bar(1)", "2)", "3)"}.
+ */
 std::vector<Span<const char>> Split(const Span<const char> &sp, char sep);
 
 } // namespace spanparsing
 
 #endif // BITCOIN_UTIL_SPANPARSING_H