feat: expose Discord channel topics to agent context

Discord channels have topic descriptions that carry meaningful context
for the agent. Currently only server name and channel name are passed
through — the topic is discarded.

Add CHANNEL_TOPIC metadata key, extract guild_channel.topic in the
Discord adapter, thread it through render_conversation_context(), and
render it in the conversation context template when present.

When no topic is set, nothing additional is rendered. Zero breaking
changes — purely additive.

Author: EZotoff

prompts/en/fragments/conversation_context.md.j2

@@ -7,4 +7,7 @@ Channel: {{ channel_name }} ({{ platform }}{% if conversation_id %}, id: `{{ con
 {%- elif conversation_id %}
 Channel ID: `{{ conversation_id }}`
 {%- endif %}
+{%- if channel_topic %}
+Topic: {{ channel_topic }}
+{%- endif %}
 Multiple users may be present. Each message is prefixed with [username].

src/agent/channel.rs

@@ -1297,11 +1297,16 @@ impl Channel {
                 .metadata
                 .get(crate::metadata_keys::CHANNEL_NAME)
                 .and_then(|v| v.as_str());
+            let channel_topic = first
+                .metadata
+                .get(crate::metadata_keys::CHANNEL_TOPIC)
+                .and_then(|v| v.as_str());
             self.conversation_context = Some(prompt_engine.render_conversation_context(
                 &first.source,
                 server_name,
                 channel_name,
                 self.conversation_id.as_deref(),
+                channel_topic,
             )?);
         }
 
@@ -1800,11 +1805,16 @@ impl Channel {
                 .metadata
                 .get(crate::metadata_keys::CHANNEL_NAME)
                 .and_then(|v| v.as_str());
+            let channel_topic = message
+                .metadata
+                .get(crate::metadata_keys::CHANNEL_TOPIC)
+                .and_then(|v| v.as_str());
             self.conversation_context = Some(prompt_engine.render_conversation_context(
                 &message.source,
                 server_name,
                 channel_name,
                 self.conversation_id.as_deref(),
+                channel_topic,
             )?);
         }
 

src/api/channels.rs

@@ -568,6 +568,7 @@ pub(super) async fn inspect_prompt(
                     server_name,
                     info.display_name.as_deref(),
                     Some(&info.id),
+                    None,
                 )
                 .ok()
         }

src/lib.rs

@@ -459,6 +459,8 @@ pub mod metadata_keys {
     pub const REPLY_TO_MESSAGE_ID: &str = "reply_to_message_id";
     /// Quoted reply text preview from the message being replied to.
     pub const REPLY_TO_TEXT: &str = "reply_to_text";
+    /// Channel topic / description (e.g. Discord channel topic).
+    pub const CHANNEL_TOPIC: &str = "channel_topic";
 }
 
 /// Inbound message from any messaging platform.

src/messaging/discord.rs

@@ -936,6 +936,15 @@ async fn build_metadata(
             guild_channel.name.clone().into(),
         );
 
+        if let Some(ref topic) = guild_channel.topic {
+            if !topic.is_empty() {
+                metadata.insert(
+                    crate::metadata_keys::CHANNEL_TOPIC.into(),
+                    topic.clone().into(),
+                );
+            }
+        }
+
         // Threads have a parent_id pointing to the text channel they were created in
         if guild_channel.thread_metadata.is_some() {
             metadata.insert("discord_is_thread".into(), true.into());

src/prompts/engine.rs

@@ -274,6 +274,7 @@ impl PromptEngine {
         server_name: Option<&str>,
         channel_name: Option<&str>,
         conversation_id: Option<&str>,
+        channel_topic: Option<&str>,
     ) -> Result<String> {
         self.render(
             "fragments/conversation_context",
@@ -282,6 +283,7 @@ impl PromptEngine {
                 server_name => server_name,
                 channel_name => channel_name,
                 conversation_id => conversation_id,
+                channel_topic => channel_topic,
             },
         )
     }