diff --git a/jgvariant-ostree/src/main/java/eu/mulk/jgvariant/ostree/Commit.java b/jgvariant-ostree/src/main/java/eu/mulk/jgvariant/ostree/Commit.java
index 43909ba..a250937 100644
--- a/jgvariant-ostree/src/main/java/eu/mulk/jgvariant/ostree/Commit.java
+++ b/jgvariant-ostree/src/main/java/eu/mulk/jgvariant/ostree/Commit.java
@@ -11,6 +11,19 @@
  * <p>Has an optional parent, a root directory, and various metadata.
  *
  * <p>Reference: {@code ostree-core.h#OSTREE_COMMIT_GVARIANT_STRING}
+ *
+ * @param metadata arbitrary metadata supplied by the user who made the commit.
+ * @param parentChecksum a (possibly {@link Checksum#isEmpty()}) reference to this commit's parent
+ *     commit.
+ * @param relatedObjects references to related commits.
+ * @param subject the subject line part of the commit message.
+ * @param body the body part of the commit message.
+ * @param timestamp UNIX epoch seconds of when the commit was done.
+ * @param rootDirTreeChecksum the checksum of the {@link DirTree} file describing the root
+ *     directory.
+ * @param rootDirMetaChecksum the checksum of the {@link DirMeta} file describing the root
+ *     directory.
+ * @see ObjectType#COMMIT
  */
 public record Commit(
     Metadata metadata,
@@ -22,6 +35,12 @@
     Checksum rootDirTreeChecksum,
     Checksum rootDirMetaChecksum) {
 
+  /**
+   * A reference to a related commit.
+   *
+   * @param ref the name of the reference.
+   * @param commitChecksum the checksum of the related commit.
+   */
   public record RelatedObject(String ref, Checksum commitChecksum) {
 
     private static final Decoder<RelatedObject> DECODER =
@@ -45,6 +64,11 @@
           Checksum.decoder(),
           Checksum.decoder());
 
+  /**
+   * Acquires a {@link Decoder} for the enclosing type.
+   *
+   * @return a possibly shared {@link Decoder}.
+   */
   public static Decoder<Commit> decoder() {
     return DECODER;
   }