diff --git a/doc/hgrc.5.txt b/doc/hgrc.5.txt
--- a/doc/hgrc.5.txt
+++ b/doc/hgrc.5.txt
@@ -151,19 +151,27 @@ hooks::
   commit;;
     Run after a changeset has been created in the local repository.
     Passed the ID of the newly created changeset in environment
-    variable $NODE.
+    variable $NODE.  Parent changeset IDs in $P1 and $P2.
   incoming;;
     Run after a changeset has been pulled, pushed, or unbundled into
     the local repository.  Passed the ID of the newly arrived
     changeset in environment variable $NODE.
   precommit;;
-    Run before starting a commit.  Exit status 0 allows the commit to
-    proceed.  Non-zero status will cause the commit to fail.
+    Run before starting a local commit.  Exit status 0 allows the
+    commit to proceed.  Non-zero status will cause the commit to
+    fail.  Parent changeset IDs in $P1 and $P2.
   pretag;;
     Run before creating a tag.  Exit status 0 allows the tag to be
     created.  Non-zero status will cause the tag to fail.  ID of
     changeset to tag in $NODE.  Name of tag in $TAG.  Tag is local if
     $LOCAL=1, in repo if $LOCAL=0.
+  pretxncommit;;
+    Run after a changeset has been created but the transaction not yet
+    committed.  Changeset is visible to hook program.  This lets you
+    validate commit message and changes.  Exit status 0 allows the
+    commit to proceed.  Non-zero status will cause the transaction to
+    be rolled back.  ID of changeset in $NODE.  Parent changeset IDs
+    in $P1 and $P2.
   tag;;
     Run after a tag is created.  ID of tagged changeset in $NODE.
     Name of tag in $TAG.  Tag is local if $LOCAL=1, in repo if