lib/PublicInbox/Config.pm    | 12 ++++++++++++
 lib/PublicInbox/ExtSearch.pm | 25 +++++++++++++++++++++++++
 lib/PublicInbox/Inbox.pm     | 51 +++++++++++++++++++++++++--------------------------
 lib/PublicInbox/WWW.pm       |  3 ++-

diff --git a/lib/PublicInbox/Config.pm b/lib/PublicInbox/Config.pm
index d57c361ad90cd8364629201021b485c7b715cb46..d425cc9b162d0d4ab7b3dcd76b7fa3f3a03c863c 100644
--- a/lib/PublicInbox/Config.pm
+++ b/lib/PublicInbox/Config.pm
@@ -89,6 +89,11 @@ 	my ($self, $name) = @_;
 	$self->{-by_name}->{$name} // _fill($self, "publicinbox.$name");
 }
 
+sub lookup_ei {
+	my ($self, $name) = @_;
+	$self->{-ei_by_name}->{$name} //= _fill_ei($self, "eindex.$name");
+}
+
 sub each_inbox {
 	my ($self, $cb, @arg) = @_;
 	# may auto-vivify if config file is non-existent:
@@ -455,6 +460,13 @@ 		}
 	}
 
 	$ibx
+}
+
+sub _fill_ei ($$) {
+	my ($self, $pfx) = @_;
+	require PublicInbox::ExtSearch;
+	my $d = $self->{"$pfx.topdir"};
+	defined($d) && -d $d ? PublicInbox::ExtSearch->new($d) : undef;
 }
 
 sub urlmatch {
diff --git a/lib/PublicInbox/ExtSearch.pm b/lib/PublicInbox/ExtSearch.pm
index 3e8ca82c65c79cf443240674bae672040eeea0ef..66c99eaa35eae88fd207930fe3165dd692ab7aa2 100644
--- a/lib/PublicInbox/ExtSearch.pm
+++ b/lib/PublicInbox/ExtSearch.pm
@@ -3,6 +3,7 @@ # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 
 # Read-only external (detached) index for cross inbox search.
 # This is a read-only counterpart to PublicInbox::ExtSearchIdx
+# and behaves like PublicInbox::Inbox AND PublicInbox::Search
 package PublicInbox::ExtSearch;
 use strict;
 use v5.10.1;
@@ -21,6 +22,8 @@ 		xpfx => "$topdir/ei".PublicInbox::Search::SCHEMA_VERSION
 	}, __PACKAGE__;
 }
 
+sub search { $_[0] } # self
+
 # overrides PublicInbox::Search::_xdb
 sub _xdb {
 	my ($self) = @_;
@@ -38,7 +41,29 @@ 	my ($self) = @_;
 	$self->{git} //= PublicInbox::Git->new("$self->{topdir}/ALL.git");
 }
 
+sub mm { undef }
+
+sub altid_map { {} }
+
+sub description {
+	my ($self) = @_;
+	($self->{description} //=
+		PublicInbox::Inbox::cat_desc("$self->{topdir}/description")) //
+		'$EINDEX_DIR/description missing';
+}
+
+sub cloneurl { [] } # TODO
+
+sub base_url { 'https://example.com/TODO/' }
+sub nntp_url { [] }
+
 no warnings 'once';
 *smsg_eml = \&PublicInbox::Inbox::smsg_eml;
+*smsg_by_mid = \&PublicInbox::Inbox::smsg_by_mid;
+*msg_by_mid = \&PublicInbox::Inbox::msg_by_mid;
+*modified = \&PublicInbox::Inbox::modified;
+*recent = \&PublicInbox::Inbox::recent;
+
+*max_git_epoch = *nntp_usable = *msg_by_path = \&mm; # undef
 
 1;
diff --git a/lib/PublicInbox/Inbox.pm b/lib/PublicInbox/Inbox.pm
index cd5c098a1b28aee65b9b25d289823101c74d7fd8..1d18cdf17ddd162e5ed26f295a186fa14bb1485a 100644
--- a/lib/PublicInbox/Inbox.pm
+++ b/lib/PublicInbox/Inbox.pm
@@ -225,16 +225,19 @@ 	}
 	$rv;
 }
 
+sub cat_desc ($) {
+	my $desc = try_cat($_[0]);
+	local $/ = "\n";
+	chomp $desc;
+	utf8::decode($desc);
+	$desc =~ s/\s+/ /smg;
+	$desc eq '' ? undef : $desc;
+}
+
 sub description {
 	my ($self) = @_;
-	($self->{description} //= do {
-		my $desc = try_cat("$self->{inboxdir}/description");
-		local $/ = "\n";
-		chomp $desc;
-		utf8::decode($desc);
-		$desc =~ s/\s+/ /smg;
-		$desc eq '' ? undef : $desc;
-	}) // '($INBOX_DIR/description missing)';
+	($self->{description} //= cat_desc("$self->{inboxdir}/description")) //
+		'($INBOX_DIR/description missing)';
 }
 
 sub cloneurl {
@@ -342,39 +345,35 @@ 	$smsg->populate($eml) unless exists($smsg->{num}); # v1 w/o SQLite
 	$eml;
 }
 
-sub mid2num($$) {
-	my ($self, $mid) = @_;
-	my $mm = mm($self) or return;
-	$mm->num_for($mid);
-}
-
 sub smsg_by_mid ($$) {
 	my ($self, $mid) = @_;
-	my $over = over($self) or return;
-	# favor the Message-ID we used for the NNTP article number:
-	defined(my $num = mid2num($self, $mid)) or return;
-	my $smsg = $over->get_art($num) or return;
-	PublicInbox::Smsg::psgi_cull($smsg);
+	my $over = $self->over or return;
+	my $smsg;
+	if (my $mm = $self->mm) {
+		# favor the Message-ID we used for the NNTP article number:
+		defined(my $num = $mm->num_for($mid)) or return;
+		$smsg = $over->get_art($num);
+	} else {
+		my ($id, $prev);
+		$smsg = $over->next_by_mid($mid, \$id, \$prev);
+	}
+	$smsg ? PublicInbox::Smsg::psgi_cull($smsg) : undef;
 }
 
 sub msg_by_mid ($$) {
 	my ($self, $mid) = @_;
-
-	over($self) or
-		return msg_by_path($self, mid2path($mid));
-
 	my $smsg = smsg_by_mid($self, $mid);
-	$smsg ? msg_by_smsg($self, $smsg) : undef;
+	$smsg ? msg_by_smsg($self, $smsg) : msg_by_path($self, mid2path($mid));
 }
 
 sub recent {
 	my ($self, $opts, $after, $before) = @_;
-	over($self)->recent($opts, $after, $before);
+	$self->over->recent($opts, $after, $before);
 }
 
 sub modified {
 	my ($self) = @_;
-	if (my $over = over($self)) {
+	if (my $over = $self->over) {
 		my $msgs = $over->recent({limit => 1});
 		if (my $smsg = $msgs->[0]) {
 			return $smsg->{ts};
diff --git a/lib/PublicInbox/WWW.pm b/lib/PublicInbox/WWW.pm
index e3b589cb78d4475c39eba9d8ca6c6f8e89e9610d..cdbcff1e1c876d176e334336ad6c315a036f5fab 100644
--- a/lib/PublicInbox/WWW.pm
+++ b/lib/PublicInbox/WWW.pm
@@ -210,7 +210,8 @@
 # returns undef if valid, array ref response if invalid
 sub invalid_inbox ($$) {
 	my ($ctx, $inbox) = @_;
-	my $ibx = $ctx->{www}->{pi_config}->lookup_name($inbox);
+	my $ibx = $ctx->{www}->{pi_config}->lookup_name($inbox) //
+			$ctx->{www}->{pi_config}->lookup_ei($inbox);
 	if (defined $ibx) {
 		$ctx->{-inbox} = $ibx;
 		return;