finalOutput already recovered a front-loaded answer when the terminal
(no-tool-call) turn was empty or a short back-reference. But some models
(glm-5.2 via a "cite" tool) front-load the prose answer into an earlier
tool-call turn and close with a terminal turn that is ONLY their sources
("Sources: [pcprice.watch](url) (...), [ebay](url) (...)"). That list is
neither empty nor a back-reference, so it was returned verbatim and the real
answer was discarded (mort issue #1418: the user got a bare sources list; the
good answer was only visible in the trace).

Add isCitationsOnly: a terminal that OPENS with a sources/citations heading,
carries a link, and is dominated by that citation structure (once heading+links
are stripped, little prose remains). Unlike a back-reference the citations are
real content, so finalOutput recovers the prior substantive answer and APPENDS
the citations below it (deduped). The dominance check keeps a real prose answer
that merely opens with "Source: ... http://..." from being misclassified; the ^
anchor keeps an answer that ends with a Sources section from matching; the
citations branch is decoupled from the terminal-length ratio so a CONCISE
front-loaded answer is still recovered; and preambleRe now applies regardless of
length so planning narration is never recovered. Healthy terminal answers are
unchanged; zero extra model calls.

Tests: TestIsCitationsOnly (19 cases incl. bold/ATX/backref/prose negatives),
new TestFinalOutput cases (concise+long-citations, source-led-not-hijacked,
long-preamble-skipped, dedup), and end-to-end
TestRun_RecoversFrontLoadedAnswerWithCitations. Full agent suite green (-race).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

@@ -23,3 +36,3 @@
 // (the loop appends it before calling this); terminal is that message's text.
 func finalOutput(msgs []llm.Message, terminal string) string {
-	if !isWeakFinal(terminal) {
+	citations := isCitationsOnly(terminal)

@@ -32,0 +47,4 @@
+		// Preserve the citations addendum below the recovered answer, unless the
+		// recovered turn already carries it verbatim (guards against a duplicate
+		// sources block when the front-loaded turn included its own citations).
+		if tail := strings.TrimSpace(terminal); !strings.Contains(rec, tail) {

@@ -43,0 +71,4 @@
+// (** / __) plus whitespace between the label and the colon/dash separator.
+// Anchored at ^ so a normal answer that merely mentions "sources" mid-sentence,
+// or ends with a "Sources:" section AFTER its prose, is never matched.
+var citationLabelRe = regexp.MustCompile(`(?i)^[\s>#*_+-]*(sources?|references?|citations?|works cited|further reading)\b[\s*_]*[:：\-—]`)

@@ -43,0 +81,4 @@
+// citationResidueCutset is trimmed from the ends of a citations terminal's
+// non-link remainder before measuring it — list bullets, separators, and the
+// short per-source annotations models add in parentheses.
+const citationResidueCutset = " \t\r\n,;.:|·•*_()[]—-"

@@ -92,0 +170,4 @@
+// accepted; a shorter one must clear a floor and, unless the terminal is a
+// citations addendum (not a rival answer, so its length is irrelevant), also
+// clearly dwarf the terminal.
+func isSubstantiveAnswer(txt, terminal string, citations bool) bool {

@@ -39,0 +45,4 @@
+		{"sources-md-links", "Sources: [pcprice.watch](https://pcprice.watch/x), [ebay](https://ebay.com/1).", true},
+		{"lowercase-bare-url", "sources: see https://example.com/a", true},
+		{"bold-label-colon-inside", "**Sources:** [a](https://a), [b](https://b)", true},
+		{"bold-label-colon-outside", "**Sources**: [a](https://a), [b](https://b)", true}, // #4: colon after the bold

@@ -182,0 +313,4 @@
+// the recovered answer with the citations appended (not the bare sources list),
+// with no extra model call.
+func TestRun_RecoversFrontLoadedAnswerWithCitations(t *testing.T) {
+	longAnswer := strings.TrimSpace(strings.Repeat("Free group calls are capped at sixty minutes. ", 6))