fix(discord): suppress link embeds in tool preview markdown links

Wrap the masked-link destination in angle brackets so Discord does not
unfurl an OG-preview embed under every tool progress bubble. quote()
percent-encodes any <> inside the URL itself, so the wrapper cannot be
broken out of.

contributors/emails/coffee@coffeebot.dev

@@ -0,0 +1 @@
+coffee-the-dev

plugins/platforms/discord/adapter.py

@@ -46,11 +46,14 @@ def _format_discord_markdown_link(label: str, url: str) -> str:
     URL label can therefore win over the Markdown destination and remain a
     broken link. Dropping only the scheme keeps the preview recognizable while
     leaving one unambiguous click target.
+
+    The destination is wrapped in angle brackets (``<url>``) so Discord does
+    not unfurl an OG-preview embed under every tool progress bubble.
     """
     label = _DISCORD_URL_LABEL_SCHEME_RE.sub("", label, count=1)
     escaped_label = _DISCORD_MARKDOWN_LINK_LABEL_RE.sub(r"\\\1", label)
     escaped_url = quote(url, safe=":/?#[]@!$&'*+,;=%")
-    return f"[{escaped_label}]({escaped_url})"
+    return f"[{escaped_label}](<{escaped_url}>)"
 
 
 class _Snowflake:

tests/gateway/test_discord_format.py

@@ -54,7 +54,7 @@ class TestDiscordToolPreviewFormatting:
 
         out = adapter.format_tool_preview(ToolPreview(visible, truncated=True, url=url))
 
-        assert out == f"[hermes-agent.nousresearch...]({url})"
+        assert out == f"[hermes-agent.nousresearch...](<{url}>)"
 
     def test_truncated_url_label_is_not_a_second_url_target(self):
         from agent.display import ToolPreview
@@ -67,7 +67,7 @@ class TestDiscordToolPreviewFormatting:
 
         assert out == (
             "[centaur.run/secrets/advanced-...]"
-            "(https://centaur.run/secrets/advanced-permissioning)"
+            "(<https://centaur.run/secrets/advanced-permissioning>)"
         )
 
     def test_link_escapes_discord_markdown_delimiters(self):
@@ -82,7 +82,7 @@ class TestDiscordToolPreviewFormatting:
 
         assert adapter.format_tool_preview(preview) == (
             r"[example.com/docs/\[beta\]...]"
-            r"(https://example.com/docs/_%28beta%29)"
+            r"(<https://example.com/docs/_%28beta%29>)"
         )
 
     def test_structured_tool_event_uses_clickable_truncated_url(self):
@@ -99,7 +99,7 @@ class TestDiscordToolPreviewFormatting:
         )
 
         assert out is not None
-        assert f"[{visible.removeprefix('https://')}]({url})" in out
+        assert f"[{visible.removeprefix('https://')}](<{url}>)" in out
 
     def test_untruncated_url_remains_plain(self):
         from agent.display import ToolPreview

tests/gateway/test_run_progress_topics.py

@@ -577,7 +577,7 @@ def test_discord_truncated_tool_url_links_to_full_destination(monkeypatch, tmp_p
     assert adapter.sent
     visible = UrlPreviewAgent.URL[:37] + "..."
     label = visible.removeprefix("https://")
-    assert f"[{label}]({UrlPreviewAgent.URL})" in adapter.sent[0]["content"]
+    assert f"[{label}](<{UrlPreviewAgent.URL}>)" in adapter.sent[0]["content"]
 
 
 class CommentaryAgent: