diff --git a/lua/fude/ui/format.lua b/lua/fude/ui/format.lua
index b9c9211..a59427a 100644
--- a/lua/fude/ui/format.lua
+++ b/lua/fude/ui/format.lua
@@ -1,4 +1,5 @@
 local M = {}
+local util = require("fude.util")
 
 --- Normalize newlines by converting CRLF and CR to LF.
 --- @param s string|nil input string
@@ -10,6 +11,10 @@ end
 --- Build status badges for a comment header (" [agent]", " [resolved]").
 --- Local review comments carry author_type ("human"|"agent") and a
 --- thread-level resolved flag; GitHub comments have neither and get "".
+--- `resolved` is a thread-level state that materialize() propagates to every
+--- comment in the thread, so the `[resolved]` badge is shown only on the
+--- thread's head comment (the root, which has no `in_reply_to_id`) to mark a
+--- resolved thread once instead of repeating it on every reply.
 --- @param comment table comment object
 --- @return string badge suffix ("" when none apply)
 function M.comment_badges(comment)
@@ -17,7 +22,7 @@ function M.comment_badges(comment)
 	if comment.author_type == "agent" then
 		badges = badges .. " [agent]"
 	end
-	if comment.resolved then
+	if comment.resolved and util.is_null(comment.in_reply_to_id) then
 		badges = badges .. " [resolved]"
 	end
 	return badges
diff --git a/tests/fude/ui_spec.lua b/tests/fude/ui_spec.lua
index ef7effb..049f217 100644
--- a/tests/fude/ui_spec.lua
+++ b/tests/fude/ui_spec.lua
@@ -61,6 +61,30 @@ describe("calculate_float_dimensions", function()
 	end)
 end)
 
+describe("comment_badges", function()
+	it("returns empty string for a plain GitHub comment", function()
+		assert.are.equal("", format.comment_badges({ user = { login = "a" } }))
+	end)
+
+	it("adds [agent] for agent-authored comments regardless of reply depth", function()
+		assert.are.equal(" [agent]", format.comment_badges({ author_type = "agent" }))
+		assert.are.equal(" [agent]", format.comment_badges({ author_type = "agent", in_reply_to_id = 1 }))
+	end)
+
+	it("adds [resolved] on a resolved thread root (no in_reply_to_id)", function()
+		assert.are.equal(" [resolved]", format.comment_badges({ resolved = true }))
+		assert.are.equal(" [resolved]", format.comment_badges({ resolved = true, in_reply_to_id = vim.NIL }))
+	end)
+
+	it("omits [resolved] on a resolved reply (has in_reply_to_id)", function()
+		assert.are.equal("", format.comment_badges({ resolved = true, in_reply_to_id = 42 }))
+	end)
+
+	it("combines [agent] and [resolved] on a resolved agent root", function()
+		assert.are.equal(" [agent] [resolved]", format.comment_badges({ author_type = "agent", resolved = true }))
+	end)
+end)
+
 describe("format_comments_for_display", function()
 	local identity = function(s)
 		return s or ""