feat(discord): render reasoning as -# subtext via display.reasoning_style (#51168)

Adds a per-platform display.reasoning_style setting (code | blockquote |
subtext) controlling how the show_reasoning summary renders on the gateway.
Discord defaults to "subtext" (-# small grey metadata text); every other
platform keeps the fenced code block. Resolves through the existing
display.platforms.<platform>.reasoning_style override chain.

gateway/display_config.py

@@ -34,6 +34,12 @@ _GLOBAL_DEFAULTS: dict[str, Any] = {
     "tool_progress": "all",
     "tool_progress_grouping": "accumulate",  # "accumulate" = edit one bubble; "separate" = one msg per tool
     "show_reasoning": False,
+    # How a reasoning/thinking summary is rendered when show_reasoning is on.
+    #   "code"      -> 💭 **Reasoning:** + fenced code block (legacy default)
+    #   "blockquote"-> each line prefixed with "> "
+    #   "subtext"   -> each line prefixed with "-# " (Discord small grey subtext)
+    # Discord defaults to "subtext"; everywhere else defaults to "code".
+    "reasoning_style": "code",
     "tool_preview_length": 0,
     "streaming": None,  # None = follow top-level streaming config
     # Gateway-only assistant/status chatter controls. These default on for
@@ -111,7 +117,10 @@ _PLATFORM_DEFAULTS: dict[str, dict[str, Any]] = {
         "tool_progress": "off",
         "busy_ack_detail": False,
     },
-    "discord":     _TIER_HIGH,
+    # Discord has a native "subtext" primitive (-# small grey text) that reads
+    # as metadata rather than content, so reasoning summaries default to it
+    # here instead of the fenced code block used elsewhere.
+    "discord":     {**_TIER_HIGH, "reasoning_style": "subtext"},
 
     # Tier 2 — edit support, often customer/workspace channels
     # Slack: tool_progress off by default — Bolt posts cannot be edited like CLI;
@@ -242,6 +251,9 @@ def _normalise(setting: str, value: Any) -> Any:
     if setting == "tool_progress_grouping":
         val = str(value).lower()
         return val if val in ("accumulate", "separate") else "accumulate"
+    if setting == "reasoning_style":
+        val = str(value).lower()
+        return val if val in ("code", "blockquote", "subtext") else "code"
     if setting == "tool_preview_length":
         try:
             return int(value)

gateway/run.py

@@ -9733,7 +9733,31 @@ class GatewayRunner(GatewayAuthorizationMixin, GatewayKanbanWatchersMixin, Gatew
                         display_reasoning += f"\n_... ({len(lines) - 15} more lines)_"
                     else:
                         display_reasoning = last_reasoning.strip()
-                    response = f"💭 **Reasoning:**\n```\n{display_reasoning}\n```\n\n{response}"
+                    # Render style is per-platform: Discord defaults to "-# "
+                    # subtext (native small grey metadata text); other
+                    # platforms keep the fenced code block.
+                    try:
+                        from gateway.display_config import resolve_display_setting
+                        _reasoning_style = resolve_display_setting(
+                            _load_gateway_config(),
+                            _platform_config_key(source.platform),
+                            "reasoning_style",
+                            "code",
+                        )
+                    except Exception:
+                        _reasoning_style = "code"
+                    if _reasoning_style == "subtext":
+                        _quoted = "\n".join(
+                            f"-# {ln}" if ln else "-#" for ln in display_reasoning.splitlines()
+                        )
+                        response = f"-# 💭 Reasoning\n{_quoted}\n\n{response}"
+                    elif _reasoning_style == "blockquote":
+                        _quoted = "\n".join(
+                            f"> {ln}" if ln else ">" for ln in display_reasoning.splitlines()
+                        )
+                        response = f"> 💭 **Reasoning:**\n{_quoted}\n\n{response}"
+                    else:
+                        response = f"💭 **Reasoning:**\n```\n{display_reasoning}\n```\n\n{response}"
 
             # Runtime-metadata footer — only on the FINAL message of the turn.
             # Off by default (display.runtime_footer.enabled=false).  When

hermes_cli/config.py

@@ -1667,6 +1667,12 @@ DEFAULT_CONFIG = {
         # applies where tool_progress is already enabled. Per-platform override
         # via display.platforms.<platform>.tool_progress_grouping.
         "tool_progress_grouping": "accumulate",
+        # How a reasoning/thinking summary renders when show_reasoning is on.
+        # "code" (default) = 💭 fenced code block; "blockquote" = "> " lines;
+        # "subtext" = "-# " lines (Discord small grey metadata text). Discord
+        # defaults to "subtext"; override per-platform via
+        # display.platforms.<platform>.reasoning_style.
+        "reasoning_style": "code",
         # Auto-delete system-notice replies (e.g. "✨ New session started!",
         # "♻ Restarting gateway…", "⚡ Stopped…") after N seconds on platforms
         # that support message deletion (currently Telegram; other platforms

tests/gateway/test_display_config.py

@@ -510,3 +510,48 @@ class TestToolProgressGrouping:
             resolve_display_setting(config, "telegram", "tool_progress_grouping")
             == "separate"
         )
+
+
+class TestReasoningStyle:
+    """Per-platform reasoning render style (code | blockquote | subtext)."""
+
+    def test_discord_defaults_to_subtext(self):
+        from gateway.display_config import resolve_display_setting
+
+        assert resolve_display_setting({}, "discord", "reasoning_style") == "subtext"
+
+    def test_other_platforms_default_to_code(self):
+        from gateway.display_config import resolve_display_setting
+
+        for plat in ("telegram", "slack", "matrix", "api_server"):
+            assert (
+                resolve_display_setting({}, plat, "reasoning_style") == "code"
+            ), plat
+
+    def test_platform_override_wins(self):
+        from gateway.display_config import resolve_display_setting
+
+        config = {"display": {"platforms": {"discord": {"reasoning_style": "blockquote"}}}}
+        assert (
+            resolve_display_setting(config, "discord", "reasoning_style") == "blockquote"
+        )
+
+    def test_global_override(self):
+        from gateway.display_config import resolve_display_setting
+
+        config = {"display": {"reasoning_style": "subtext"}}
+        assert (
+            resolve_display_setting(config, "telegram", "reasoning_style") == "subtext"
+        )
+
+    def test_invalid_value_falls_back_to_code(self):
+        from gateway.display_config import resolve_display_setting
+
+        config = {"display": {"reasoning_style": "bogus"}}
+        assert resolve_display_setting(config, "telegram", "reasoning_style") == "code"
+
+    def test_case_insensitive(self):
+        from gateway.display_config import resolve_display_setting
+
+        config = {"display": {"reasoning_style": "SUBTEXT"}}
+        assert resolve_display_setting(config, "telegram", "reasoning_style") == "subtext"