diff --git a/gateway/platforms/matrix.py b/gateway/platforms/matrix.py
index cccb4d70e..a649bb91e 100644
--- a/gateway/platforms/matrix.py
+++ b/gateway/platforms/matrix.py
@@ -2799,11 +2799,11 @@ class MatrixAdapter(BasePlatformAdapter):
     def _markdown_to_html(self, text: str) -> str:
         """Convert Markdown to Matrix-compatible HTML (org.matrix.custom.html).
 
-        Uses the ``markdown`` library when available (installed with the
-        ``matrix`` extra).  Falls back to a comprehensive regex converter
-        that handles fenced code blocks, inline code, headers, bold,
-        italic, strikethrough, links, blockquotes, lists, and horizontal
-        rules — everything the Matrix HTML spec allows.
+        Uses the ``markdown`` library (a core dependency) when available.
+        Falls back to a comprehensive regex converter that handles fenced
+        code blocks, inline code, headers, bold, italic, strikethrough,
+        links, blockquotes, lists, and horizontal rules — everything the
+        Matrix HTML spec allows.
         """
         try:
             import markdown as _md
diff --git a/pyproject.toml b/pyproject.toml
index 0ce637528..2b12246e0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -61,6 +61,16 @@ dependencies = [
   "prompt_toolkit==3.0.52",
   # Cron scheduler (built-in feature — scheduled cron/interval jobs use croniter).
   "croniter==6.0.0",
+  # Markdown -> HTML conversion for rich message delivery (Matrix
+  # `formatted_body`, and the `send_message` tool's HTML path). Now on the
+  # DEFAULT delivery path, not matrix-specific: without it both
+  # gateway/platforms/matrix.py and tools/send_message_tool.py silently fall
+  # back to plain text, so cron/agent deliveries render raw `##`/`**`/tables
+  # in clients like Element (see #32486). Pure-Python py3-none-any wheel
+  # (~108KB, no compiled extensions, no platform constraints), so unlike the
+  # matrix extra's `mautrix`/`python-olm` it's safe to ship everywhere — keeps
+  # it out of the lazy-install path that exists only for the heavy matrix deps.
+  "Markdown==3.10.2",
   # Skills Hub (GitHub App JWT auth — optional, only needed for bot identity)
   "PyJWT[crypto]==2.12.1",  # CVE-2026-32597
   # Windows has no IANA tzdata shipped with the OS, so Python's ``zoneinfo``
@@ -104,7 +114,7 @@ dev = ["debugpy==1.8.20", "pytest==9.0.2", "pytest-asyncio==1.3.0", "pytest-time
 messaging = ["python-telegram-bot[webhooks]==22.6", "discord.py[voice]==2.7.1", "aiohttp==3.13.3", "brotlicffi==1.2.0.1", "slack-bolt==1.27.0", "slack-sdk==3.40.1", "qrcode==7.4.2"]
 cron = []  # croniter is now a core dependency; this extra kept for back-compat
 slack = ["slack-bolt==1.27.0", "slack-sdk==3.40.1", "aiohttp==3.13.3"]
-matrix = ["mautrix[encryption]==0.21.0", "Markdown==3.10.2", "aiosqlite==0.22.1", "asyncpg==0.31.0", "aiohttp-socks==0.11.0"]
+matrix = ["mautrix[encryption]==0.21.0", "aiosqlite==0.22.1", "asyncpg==0.31.0", "aiohttp-socks==0.11.0"]
 # WeCom callback-mode adapter — parses untrusted XML POST bodies from
 # WeCom-controlled callback endpoints, so we use defusedxml (drop-in
 # replacement for stdlib xml.etree.ElementTree) to block billion-laughs
diff --git a/tools/lazy_deps.py b/tools/lazy_deps.py
index 0c0a2a6e9..5b5878eb4 100644
--- a/tools/lazy_deps.py
+++ b/tools/lazy_deps.py
@@ -135,7 +135,6 @@ LAZY_DEPS: dict[str, tuple[str, ...]] = {
     ),
     "platform.matrix": (
         "mautrix[encryption]==0.21.0",
-        "Markdown==3.10.2",
         "aiosqlite==0.22.1",
         "asyncpg==0.31.0",
         "aiohttp-socks==0.11.0",
diff --git a/uv.lock b/uv.lock
index b10a215c9..c90be9add 100644
--- a/uv.lock
+++ b/uv.lock
@@ -1398,6 +1398,7 @@ dependencies = [
     { name = "fire" },
     { name = "httpx", extra = ["socks"] },
     { name = "jinja2" },
+    { name = "markdown" },
     { name = "openai" },
     { name = "pathspec" },
     { name = "prompt-toolkit" },
@@ -1502,7 +1503,6 @@ matrix = [
     { name = "aiohttp-socks" },
     { name = "aiosqlite" },
     { name = "asyncpg" },
-    { name = "markdown" },
     { name = "mautrix", extra = ["encryption"] },
 ]
 mcp = [
@@ -1642,7 +1642,7 @@ requires-dist = [
     { name = "httpx", extras = ["socks"], specifier = "==0.28.1" },
     { name = "jinja2", specifier = "==3.1.6" },
     { name = "lark-oapi", marker = "extra == 'feishu'", specifier = "==1.5.3" },
-    { name = "markdown", marker = "extra == 'matrix'", specifier = "==3.10.2" },
+    { name = "markdown", specifier = "==3.10.2" },
     { name = "mautrix", extras = ["encryption"], marker = "extra == 'matrix'", specifier = "==0.21.0" },
     { name = "mcp", marker = "extra == 'computer-use'", specifier = "==1.26.0" },
     { name = "mcp", marker = "extra == 'dev'", specifier = "==1.26.0" },