refactor(gateway): share markdown link formatting

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 stripping,
+message deduplication, text batch aggregation, markdown formatting/stripping,
 and thread participation tracking.
 """
 
@@ -12,6 +12,7 @@ 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
 
@@ -181,7 +182,20 @@ class TextBatchAggregator:
 
 # ─── Markdown Stripping ──────────────────────────────────────────────────────
 
-# Pre-compiled regexes for performance
+# 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
 _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 quote, urljoin
+from urllib.parse import urljoin
 
 from agent.async_utils import (
     consume_detached_task_result as _consume_background_task_result,
@@ -121,7 +121,12 @@ except ImportError:
 
 from gateway.config import Platform, PlatformConfig
 
-from gateway.platforms.helpers import MessageDeduplicator, ThreadParticipationTracker, convert_table_to_bullets
+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 (
     BasePlatformAdapter,
@@ -982,9 +987,7 @@ class DiscordAdapter(BasePlatformAdapter):
         if not preview.url:
             return preview.text
 
-        label = re.sub(r"([\\\[\]])", r"\\\1", preview.text)
-        href = quote(preview.url, safe=":/?#[]@!$&'*+,;=%")
-        return f"[{label}]({href})"
+        return format_markdown_link(preview.text, preview.url)
 
     def __init__(self, config: PlatformConfig):
         super().__init__(config, Platform.DISCORD)

tests/gateway/test_markdown_helpers.py

@@ -0,0 +1,9 @@
+"""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)"