refactor(discord): keep link formatting adapter-local

gateway/platforms/helpers.py

@@ -1,7 +1,7 @@
 """Shared helper classes for gateway platform adapters.
 
 Extracts common patterns that were duplicated across 5-7 adapters:
-message deduplication, text batch aggregation, markdown formatting/stripping,
+message deduplication, text batch aggregation, markdown stripping,
 and thread participation tracking.
 """
 
@@ -12,7 +12,6 @@ import re
 import time
 from pathlib import Path
 from typing import TYPE_CHECKING, Dict
-from urllib.parse import quote
 
 from utils import atomic_json_write
 
@@ -182,20 +181,7 @@ class TextBatchAggregator:
 
 # ─── Markdown Stripping ──────────────────────────────────────────────────────
 
-# Standard Markdown links are supported by several rich-text adapters. Keep
-# delimiter escaping here; platform-specific dialect conversion stays in each
-# adapter.
-_MARKDOWN_LINK_LABEL_RE = re.compile(r"([\\\[\]])")
-
-
-def format_markdown_link(label: str, url: str) -> str:
-    """Return a standard Markdown link with safe label and destination text."""
-    escaped_label = _MARKDOWN_LINK_LABEL_RE.sub(r"\\\1", label)
-    escaped_url = quote(url, safe=":/?#[]@!$&'*+,;=%")
-    return f"[{escaped_label}]({escaped_url})"
-
-
-# Pre-compiled regexes for Markdown stripping
+# Pre-compiled regexes for performance
 _RE_BOLD = re.compile(r"\*\*(.+?)\*\*", re.DOTALL)
 _RE_ITALIC_STAR = re.compile(r"\*(.+?)\*", re.DOTALL)
 _RE_BOLD_UNDER = re.compile(r"\b__(?![\s_])(.+?)(?<![\s_])__\b", re.DOTALL)

plugins/platforms/discord/adapter.py

@@ -26,7 +26,7 @@ import time
 from collections import defaultdict
 from contextlib import suppress
 from typing import Callable, Dict, List, Optional, Any, Tuple
-from urllib.parse import urljoin
+from urllib.parse import quote, urljoin
 
 from agent.async_utils import (
     consume_detached_task_result as _consume_background_task_result,
@@ -35,6 +35,15 @@ from agent.display import ToolPreview
 
 logger = logging.getLogger(__name__)
 
+_DISCORD_MARKDOWN_LINK_LABEL_RE = re.compile(r"([\\\[\]])")
+
+
+def _format_discord_markdown_link(label: str, url: str) -> str:
+    """Return a Discord Markdown link with escaped delimiters."""
+    escaped_label = _DISCORD_MARKDOWN_LINK_LABEL_RE.sub(r"\\\1", label)
+    escaped_url = quote(url, safe=":/?#[]@!$&'*+,;=%")
+    return f"[{escaped_label}]({escaped_url})"
+
 
 class _Snowflake:
     """Minimal object exposing ``.id`` — satisfies discord.py's Snowflake
@@ -125,7 +134,6 @@ from gateway.platforms.helpers import (
     MessageDeduplicator,
     ThreadParticipationTracker,
     convert_table_to_bullets,
-    format_markdown_link,
 )
 from utils import atomic_json_write, env_float, env_int
 from gateway.platforms.base import (
@@ -987,7 +995,7 @@ class DiscordAdapter(BasePlatformAdapter):
         if not preview.url:
             return preview.text
 
-        return format_markdown_link(preview.text, preview.url)
+        return _format_discord_markdown_link(preview.text, preview.url)
 
     def __init__(self, config: PlatformConfig):
         super().__init__(config, Platform.DISCORD)

tests/gateway/test_discord_format.py

@@ -56,6 +56,21 @@ class TestDiscordToolPreviewFormatting:
 
         assert out == f"[{visible}]({url})"
 
+    def test_link_escapes_discord_markdown_delimiters(self):
+        from agent.display import ToolPreview
+
+        adapter = _make_discord_adapter()
+        preview = ToolPreview(
+            r"https://example.com/docs/[beta]...",
+            truncated=True,
+            url="https://example.com/docs/_(beta)",
+        )
+
+        assert adapter.format_tool_preview(preview) == (
+            r"[https://example.com/docs/\[beta\]...]"
+            r"(https://example.com/docs/_%28beta%29)"
+        )
+
     def test_structured_tool_event_uses_clickable_truncated_url(self):
         from gateway.stream_events import ToolCallChunk
 

tests/gateway/test_markdown_helpers.py

@@ -1,9 +0,0 @@
-"""Tests for shared platform Markdown formatting helpers."""
-
-from gateway.platforms.helpers import format_markdown_link
-
-
-def test_format_markdown_link_escapes_label_and_destination_delimiters():
-    assert format_markdown_link(
-        r"docs [beta]", "https://example.com/a_(draft)"
-    ) == r"[docs \[beta\]](https://example.com/a_%28draft%29)"