diff --git a/CUSTOMIZATION.md b/CUSTOMIZATION.md
index 87e60390..628a3e20 100644
--- a/CUSTOMIZATION.md
+++ b/CUSTOMIZATION.md
@@ -327,9 +327,17 @@ Users can also override the team/project mapping on a per-comment basis by inclu
 
 ### Customizing Slack routing
 
-Slack uses `DEFAULT_REPO_OWNER` and `DEFAULT_REPO_NAME` as the fallback when no repo is specified in a message.
+Slack repo resolution (`get_slack_repo_config` in `agent/webapp.py`) checks, in order:
 
-Users can override per-message with `repo:owner/name` syntax in their Slack message. A shorthand `repo:name` (without the org) is also supported — the org defaults to `DEFAULT_REPO_OWNER`.
+1. Repo carried over from the existing Slack thread's metadata.
+2. A `repo:owner/name` (or GitHub URL) token in the channel's **topic or purpose** (its "description"). This lets a channel be pinned to a repo without anyone repeating it per-message.
+3. The triggering user's dashboard `default_repo`.
+4. The team default repo.
+5. `SLACK_REPO_OWNER`/`SLACK_REPO_NAME`, falling back to `DEFAULT_REPO_OWNER`/`DEFAULT_REPO_NAME`.
+
+Users can still override per-message with `repo:owner/name` syntax in their Slack message (this is read from the message text by the agent). A shorthand `repo:name` (without the org) is also supported — the org defaults to `DEFAULT_REPO_OWNER`.
+
+Reading the channel topic/purpose requires the bot's Slack token to have the `channels:read` (and `groups:read` for private channels) scope so `conversations.info` succeeds.
 
 ### Adding a new trigger
 
diff --git a/agent/utils/slack.py b/agent/utils/slack.py
index f53354f8..5d3522a9 100644
--- a/agent/utils/slack.py
+++ b/agent/utils/slack.py
@@ -438,6 +438,51 @@ async def get_slack_user_info(user_id: str) -> dict[str, Any] | None:
     return None
 
 
+async def get_slack_channel_info(channel_id: str) -> dict[str, Any] | None:
+    """Get Slack channel details (including topic/purpose) by channel ID."""
+    if not SLACK_BOT_TOKEN:
+        return None
+
+    async with httpx.AsyncClient() as http_client:
+        try:
+            response = await http_client.get(
+                f"{SLACK_API_BASE_URL}/conversations.info",
+                headers=_slack_headers(),
+                params={"channel": channel_id},
+            )
+            response.raise_for_status()
+            data = response.json()
+            if not data.get("ok"):
+                logger.warning("Slack conversations.info failed: %s", data.get("error"))
+                return None
+            channel = data.get("channel")
+            if isinstance(channel, dict):
+                return channel
+        except httpx.HTTPError:
+            logger.exception("Slack conversations.info request failed")
+    return None
+
+
+def extract_channel_description_text(channel: dict[str, Any] | None) -> str:
+    """Combine a Slack channel's topic and purpose text into one string."""
+    if not isinstance(channel, dict):
+        return ""
+    parts: list[str] = []
+    for key in ("topic", "purpose"):
+        section = channel.get(key)
+        if isinstance(section, dict):
+            value = section.get("value")
+            if isinstance(value, str) and value.strip():
+                parts.append(value.strip())
+    return "\n".join(parts)
+
+
+async def get_slack_channel_description(channel_id: str) -> str:
+    """Fetch a Slack channel's combined topic + purpose text."""
+    channel = await get_slack_channel_info(channel_id)
+    return extract_channel_description_text(channel)
+
+
 async def get_slack_user_names(user_ids: list[str]) -> dict[str, str]:
     """Get display names for a set of Slack user IDs."""
     unique_ids = sorted({user_id for user_id in user_ids if isinstance(user_id, str) and user_id})
diff --git a/agent/webapp.py b/agent/webapp.py
index d181f599..f0e90995 100644
--- a/agent/webapp.py
+++ b/agent/webapp.py
@@ -87,6 +87,7 @@ from .utils.slack import (
     GitHubPrRef,
     fetch_slack_thread_messages,
     format_slack_messages_for_prompt,
+    get_slack_channel_description,
     get_slack_user_info,
     get_slack_user_names,
     post_slack_thread_reply,
@@ -573,9 +574,11 @@ async def get_slack_repo_config(
 
     Priority:
         1. Repo carried over from the existing Slack thread's metadata.
-        2. The triggering user's dashboard ``default_repo`` (if they have a
+        2. A ``repo:owner/name`` token in the channel's topic/purpose.
+        3. The triggering user's dashboard ``default_repo`` (if they have a
            profile and their Slack email maps to a known GitHub login).
-        3. ``SLACK_REPO_*`` env defaults.
+        4. Team default repo.
+        5. ``SLACK_REPO_*`` env defaults.
     """
     default_owner = SLACK_REPO_OWNER.strip() or DEFAULT_REPO_OWNER
     default_name = SLACK_REPO_NAME.strip() or DEFAULT_REPO_NAME
@@ -596,6 +599,24 @@ async def get_slack_repo_config(
                 thread_id,
             )
 
+    if not repo_config:
+        try:
+            channel_description = await get_slack_channel_description(channel_id)
+            if channel_description:
+                channel_repo_config = extract_repo_from_text(
+                    channel_description, default_owner=default_owner
+                )
+                if channel_repo_config:
+                    logger.info(
+                        "Applying repo from Slack channel %s description: %s/%s",
+                        channel_id,
+                        channel_repo_config["owner"],
+                        channel_repo_config["name"],
+                    )
+                    repo_config = channel_repo_config
+        except Exception:  # noqa: BLE001
+            logger.exception("Failed to resolve repo from Slack channel description")
+
     if not repo_config and slack_user_id:
         try:
             slack_user = await get_slack_user_info(slack_user_id)
diff --git a/tests/test_repo_extraction.py b/tests/test_repo_extraction.py
index 4ea57bd2..dc47b5f6 100644
--- a/tests/test_repo_extraction.py
+++ b/tests/test_repo_extraction.py
@@ -6,6 +6,7 @@ from unittest.mock import AsyncMock, patch
 import pytest
 
 from agent.utils.repo import extract_repo_from_text
+from agent.utils.slack import extract_channel_description_text
 
 
 class TestExtractRepoFromText:
@@ -54,6 +55,33 @@ class TestExtractRepoFromText:
         assert result == {"owner": "my-org", "name": "my-repo"}
 
 
+class TestExtractChannelDescriptionText:
+    def test_combines_topic_and_purpose(self) -> None:
+        channel = {
+            "topic": {"value": "repo:my-org/my-repo"},
+            "purpose": {"value": "Team channel"},
+        }
+        assert extract_channel_description_text(channel) == "repo:my-org/my-repo\nTeam channel"
+
+    def test_handles_missing_sections(self) -> None:
+        assert extract_channel_description_text({"topic": {"value": "hi"}}) == "hi"
+
+    def test_empty_for_none(self) -> None:
+        assert extract_channel_description_text(None) == ""
+
+    def test_empty_for_blank_values(self) -> None:
+        channel = {"topic": {"value": "  "}, "purpose": {"value": ""}}
+        assert extract_channel_description_text(channel) == ""
+
+    def test_repo_token_extractable_from_description(self) -> None:
+        channel = {"topic": {"value": "Use repo:langchain-ai/open-swe here"}, "purpose": {}}
+        description = extract_channel_description_text(channel)
+        assert extract_repo_from_text(description) == {
+            "owner": "langchain-ai",
+            "name": "open-swe",
+        }
+
+
 class TestLinearWebhookRepoOverride:
     """Test that the Linear webhook handler checks comment body for repo config first."""