diff --git a/define/build.go b/define/build.go
index 5648f8bbb..0a4771208 100644
--- a/define/build.go
+++ b/define/build.go
@@ -273,6 +273,10 @@ type BuildOptions struct {
 	// the build was unsuccessful.
 	ForceRmIntermediateCtrs bool
 	// BlobDirectory is a directory which we'll use for caching layer blobs.
+	//
+	// This option will be overridden for cache pulls if
+	// CachePullDestinationLookupReferenceFunc is set, and overridden for cache pushes if
+	// CachePushSourceLookupReferenceFunc is set.
 	BlobDirectory string
 	// Target the targeted FROM in the Dockerfile to build.
 	Target string
@@ -349,10 +353,14 @@ type BuildOptions struct {
 	// CachePullDestinationLookupReferenceFunc is an optional generator
 	// function which provides a LookupReferenceFunc used to look up
 	// destination references for cache pulls.
+	//
+	// BlobDirectory will be ignored for cache pulls if this option is set.
 	CachePullDestinationLookupReferenceFunc func(srcRef types.ImageReference) libimage.LookupReferenceFunc
 	// CachePushSourceLookupReferenceFunc is an optional generator function
 	// which provides a LookupReferenceFunc used to look up source
 	// references for cache pushes.
+	//
+	// BlobDirectory will be ignored for cache pushes if this option is set.
 	CachePushSourceLookupReferenceFunc func(dest types.ImageReference) libimage.LookupReferenceFunc
 	// CachePushDestinationLookupReferenceFunc is an optional
 	// LookupReferenceFunc used to look up destination references for cache
diff --git a/pull.go b/pull.go
index abfe5e8b0..13c2bfbbc 100644
--- a/pull.go
+++ b/pull.go
@@ -33,6 +33,8 @@ type PullOptions struct {
 	// BlobDirectory is the name of a directory in which we'll attempt to
 	// store copies of layer blobs that we pull down, if any.  It should
 	// already exist.
+	//
+	// Not applicable if DestinationLookupReferenceFunc is set.
 	BlobDirectory string
 	// AllTags is a boolean value that determines if all tagged images
 	// will be downloaded from the repository. The default is false.
@@ -54,7 +56,7 @@ type PullOptions struct {
 	// references.
 	SourceLookupReferenceFunc libimage.LookupReferenceFunc
 	// DestinationLookupReference provides a function to look up destination
-	// references.
+	// references. Overrides BlobDirectory, if set.
 	DestinationLookupReferenceFunc libimage.LookupReferenceFunc
 }
 
diff --git a/push.go b/push.go
index 6acbb82ee..9d9d7a88b 100644
--- a/push.go
+++ b/push.go
@@ -66,6 +66,8 @@ type PushOptions struct {
 	// prebuilt copies of layer blobs that we might otherwise need to
 	// regenerate from on-disk layers, substituting them in the list of
 	// blobs to copy whenever possible.
+	//
+	// Not applicable if SourceLookupReferenceFunc is set.
 	BlobDirectory string
 	// Quiet is a boolean value that determines if minimal output to
 	// the user will be displayed, this is best used for logging.
@@ -91,7 +93,7 @@ type PushOptions struct {
 	// indexing. i.e. 0 is the first layer, -1 is the last (top-most) layer.
 	OciEncryptLayers *[]int
 	// SourceLookupReference provides a function to look up source
-	// references.
+	// references. Overrides BlobDirectory, if set.
 	SourceLookupReferenceFunc libimage.LookupReferenceFunc
 	// DestinationLookupReference provides a function to look up destination
 	// references.