feat: slack-search MCP server for community thread search #1268

zzstoatzz · 2026-01-09T08:15:28Z

Summary

Adds a FastMCP server in examples/slack_search/ for searching Prefect Slack community thread summaries
Stores thread summaries in Turso with Voyage AI embeddings for semantic search
Dynamic Literal types for topic/channel filters populated at startup
get_thread_messages tool fetches actual Slack conversation content via API
Includes migration script for normalizing topic labels

Tools

search(query, topic?, channel?) - text search across thread summaries
similar(query, topic?, channel?) - semantic search using embeddings
get_thread(key) - get full AI summary + metadata
get_thread_messages(key) - fetch actual Slack messages from thread
get_stats() - index statistics
list_topics() / list_channels() - available filters

Test plan

Verified MCP server starts and loads categories from Turso
Tested text search and semantic search return results with URLs
Tested get_thread_messages fetches actual Slack content
Ran topic normalization migration on production data

🤖 Generated with Claude Code

🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

TURSO_TOKEN had surrounding quotes causing JWT Base64 decode error 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

pydantic-settings only strips quotes from .env files, not from env vars set directly in the deployment environment 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

computed field constructs clickable URL from key parts 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

- adds SLACK_API_TOKEN env var - new tool fetches real messages from Slack API via conversations.replies - returns structured ThreadContent with messages, url, timestamps 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

Copilot

Pull request overview

This PR adds a FastMCP server for searching Prefect Slack community thread summaries with semantic and text search capabilities. The implementation refactors configuration management to use pydantic-settings, adds a new tool to fetch actual Slack messages, and includes a migration script for normalizing topic labels.

Key changes:

Introduced pydantic-settings for centralized configuration management with environment variable support
Added get_thread_messages tool to fetch raw Slack conversation content via the Slack API
Fixed URL and key parsing logic for ThreadSummary (corrected array indices)

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
pyproject.toml	Added pydantic-settings>=2.0 dependency
uv.lock	Updated lock file with pydantic-settings dependency
client.py	Refactored to use Settings class with pydantic-settings; added slack_get_thread function
server.py	Refactored _load_categories to use Settings; added get_thread_messages tool
_types.py	Fixed key parsing indices; added URL computed fields and new SlackMessage/ThreadContent types
normalize_topics.py	New migration script for normalizing topic labels in database

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

Copilot · 2026-01-09T08:22:32Z

examples/slack_search/src/slack_search/server.py

        )
-        resp.raise_for_status()
+        if resp.status_code >= 400:
+            raise RuntimeError(f"Turso HTTP {resp.status_code}: {resp.text}")


The error message includes the full response text which could potentially expose sensitive information like authentication tokens or internal server details. Consider sanitizing the error message or logging it separately while showing a generic error to users.

Suggested change

raise RuntimeError(f"Turso HTTP {resp.status_code}: {resp.text}")

raise RuntimeError(f"Turso HTTP {resp.status_code}")

Copilot · 2026-01-09T08:22:33Z

examples/slack_search/src/slack_search/client.py

+        timeout=30,
+    )
+    if response.status_code >= 400:
+        raise RuntimeError(f"Turso HTTP {response.status_code} for {url}: {response.text}")


The error message includes the full response text which could potentially expose sensitive information like authentication tokens or internal server details. Consider sanitizing the error message or logging it separately while showing a generic error to users.

Suggested change

raise RuntimeError(f"Turso HTTP {response.status_code} for {url}: {response.text}")

raise RuntimeError(f"Turso HTTP {response.status_code} for {url}")

Copilot · 2026-01-09T08:22:33Z

examples/slack_search/scripts/normalize_topics.py

+    turso_url = os.environ.get("TURSO_URL", "").strip().strip('"')
+    turso_token = os.environ.get("TURSO_TOKEN", "").strip().strip('"')
+    if turso_url.startswith("libsql://"):
+        turso_url = turso_url[len("libsql://") :]


The function doesn't validate that host and token are non-empty before returning. If environment variables are not set, this will return empty strings and cause cryptic errors later. Consider adding validation to raise a clear error message if credentials are missing.

Suggested change

turso_url = turso_url[len("libsql://") :]

turso_url = turso_url[len("libsql://") :]

missing = []

if not turso_url:

missing.append("TURSO_URL")

if not turso_token:

missing.append("TURSO_TOKEN")

if missing:

raise RuntimeError(

f"Missing required environment variable(s): {', '.join(missing)}. "

"Please set them before running this script."

)

Copilot · 2026-01-09T08:22:33Z

examples/slack_search/src/slack_search/server.py


+@mcp.tool
+async def get_thread_messages(key: str) -> ThreadContent | None:
+    """fetch actual messages from a Slack thread.


The docstring style is inconsistent with the get_thread function above. The first line should start with a capital letter and end with a period to match the established convention (e.g., "Fetch actual messages from a Slack thread.").

Suggested change

"""fetch actual messages from a Slack thread.

"""Fetch actual messages from a Slack thread.

Copilot · 2026-01-09T08:22:34Z

examples/slack_search/src/slack_search/server.py

+    """fetch actual messages from a Slack thread.
+
+    retrieves the full conversation content from Slack's API,
+    not just the AI summary. requires SLACK_API_TOKEN.
+
+    args:
+        key: the thread key (from search/similar results)
+
+    returns:
+        thread content with all messages, or None if not found


The docstring style is inconsistent with the get_thread function above. Lines should start with capital letters to match the established convention (e.g., "Retrieves the full conversation..." and "Args:" and "Returns:").

Suggested change

"""fetch actual messages from a Slack thread.

retrieves the full conversation content from Slack's API,

not just the AI summary. requires SLACK_API_TOKEN.

args:

key: the thread key (from search/similar results)

returns:

thread content with all messages, or None if not found

"""Fetch actual messages from a Slack thread.

Retrieves the full conversation content from Slack's API,

not just the AI summary. Requires SLACK_API_TOKEN.

Args:

key: The thread key (from search/similar results).

Returns:

Thread content with all messages, or None if not found.

Copilot · 2026-01-09T08:22:34Z

examples/slack_search/src/slack_search/client.py

+    response = httpx.post(
+        url,
+        headers={
+            "Authorization": f"Bearer {settings.turso_token}",
+            "Content-Type": "application/json",
+        },
+        json=payload,
+        timeout=30,
+    )


The turso_query function is declared as async but uses synchronous httpx.post instead of an async client. This should either use httpx.AsyncClient or the function should not be async. The current implementation will block the event loop.

Suggested change

response = httpx.post(

url,

headers={

"Authorization": f"Bearer {settings.turso_token}",

"Content-Type": "application/json",

},

json=payload,

timeout=30,

)

async with httpx.AsyncClient() as client:

response = await client.post(

url,

headers={

"Authorization": f"Bearer {settings.turso_token}",

"Content-Type": "application/json",

},

json=payload,

timeout=30,

)

Copilot · 2026-01-09T08:22:34Z

examples/slack_search/src/slack_search/_types.py

+            from datetime import datetime
+
+            try:
+                dt = datetime.fromtimestamp(float(self.ts))


Using datetime.fromtimestamp without specifying a timezone will use the local timezone, which can lead to inconsistent behavior across different environments. Consider using datetime.fromtimestamp with timezone awareness (e.g., tz=timezone.utc) or datetime.utcfromtimestamp for consistent UTC timestamps.

Suggested change

from datetime import datetime

try:

dt = datetime.fromtimestamp(float(self.ts))

from datetime import datetime, timezone

try:

dt = datetime.fromtimestamp(float(self.ts), tz=timezone.utc)

Copilot · 2026-01-09T08:22:35Z

examples/slack_search/src/slack_search/server.py

+    channel = parts[6]
+    thread_ts = parts[7]
+
+    messages = await slack_get_thread(channel, thread_ts)


The function doesn't handle the case where slack_get_thread might raise an exception (e.g., authentication failure, network errors, or invalid channel/thread_ts). This could cause the tool to fail without a meaningful error message. Consider wrapping the slack_get_thread call in a try-except block to provide better error messages.

Suggested change

messages = await slack_get_thread(channel, thread_ts)

try:

messages = await slack_get_thread(channel, thread_ts)

except Exception as e:

# Log a meaningful error message instead of letting the exception crash the tool.

print(f"error: failed to fetch Slack thread {channel}/{thread_ts}: {e}")

return None

Copilot · 2026-01-09T08:22:35Z

examples/slack_search/scripts/normalize_topics.py

+        if not meta_raw:
+            continue
+
+        meta = json.loads(meta_raw)


The json.loads call could raise a JSONDecodeError if the metadata contains invalid JSON. This would cause the migration to fail completely. Consider wrapping this in a try-except block to skip malformed metadata and log a warning instead.

Copilot · 2026-01-09T08:22:35Z

examples/slack_search/src/slack_search/server.py

+    ts_clean = thread_ts.replace(".", "")
+    url = f"https://{workspace}.slack.com/archives/{channel}/p{ts_clean}"


The URL construction logic here duplicates the logic in ThreadSummary.url (lines 37-44 in _types.py). Consider extracting this into a shared utility function or reusing the computed field logic to maintain consistency and reduce code duplication.

- Add RETENTION_DAYS constant (90 days) - Filter search/similar queries by thread_ts > cutoff - Uses json_extract to filter on metadata.thread_ts

zzstoatzz and others added 11 commits January 9, 2026 01:16

debug: capture Turso error response body

6758960

🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

debug: strip env vars and improve error messages

5ecdb4e

🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

debug: add error logging to startup category load

2655a97

🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

debug: add explicit baton field to Turso requests

c298091

🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

fix: use sync httpx.post like the working scripts

a709af5

🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

fix: strip quotes from env var values

1204985

TURSO_TOKEN had surrounding quotes causing JWT Base64 decode error 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

refactor: use pydantic-settings for env var handling

192da09

🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

feat: add Slack thread URL to search results

f50d0b8

computed field constructs clickable URL from key parts 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <[email protected]>

feat: add topic normalization migration script

5238388

Copilot AI review requested due to automatic review settings January 9, 2026 08:15

github-actions bot added the example label Jan 9, 2026

Copilot started reviewing on behalf of zzstoatzz January 9, 2026 08:15 View session

Copilot AI reviewed Jan 9, 2026

View reviewed changes

zzstoatzz force-pushed the main branch from 006a806 to d7a12b2 Compare January 9, 2026 18:18

fix: filter out threads older than 90 days (Slack retention)

c16490a

- Add RETENTION_DAYS constant (90 days) - Filter search/similar queries by thread_ts > cutoff - Uses json_extract to filter on metadata.thread_ts

zzstoatzz force-pushed the main branch from 28a1c6e to c16490a Compare January 9, 2026 19:12

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feat: slack-search MCP server for community thread search #1268

feat: slack-search MCP server for community thread search #1268

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	raise RuntimeError(f"Turso HTTP {resp.status_code}: {resp.text}")
	raise RuntimeError(f"Turso HTTP {resp.status_code}")

	raise RuntimeError(f"Turso HTTP {response.status_code} for {url}: {response.text}")
	raise RuntimeError(f"Turso HTTP {response.status_code} for {url}")

-        turso_url = turso_url[len("libsql://") :]
+        turso_url = turso_url[len("libsql://") :]
+    missing = []
+    if not turso_url:
+        missing.append("TURSO_URL")
+    if not turso_token:
+        missing.append("TURSO_TOKEN")
+    if missing:
+        raise RuntimeError(
+            f"Missing required environment variable(s): {', '.join(missing)}. "
+            "Please set them before running this script."
+        )

	"""fetch actual messages from a Slack thread.
	"""Fetch actual messages from a Slack thread.

-    messages = await slack_get_thread(channel, thread_ts)
+    try:
+        messages = await slack_get_thread(channel, thread_ts)
+    except Exception as e:
+        # Log a meaningful error message instead of letting the exception crash the tool.
+        print(f"error: failed to fetch Slack thread {channel}/{thread_ts}: {e}")
+        return None

		ts_clean = thread_ts.replace(".", "")
		url = f"https://{workspace}.slack.com/archives/{channel}/p{ts_clean}"

feat: slack-search MCP server for community thread search #1268

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zzstoatzz commented Jan 9, 2026

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