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Evaluation record · mcp-server-slack

MCP Slack Server

v2025.4.24

Anthropic (Archived)

MCPcommunicationcollaborationmcpmodel-context-protocol
76
Strong
About This MCP

ARCHIVED: Former Anthropic reference MCP server for Slack workspace interaction, archived 2025-05-29 to the servers-archived repository. NO LONGER MAINTAINED and no security guarantees are provided for archived servers. Slack now ships an official Slack MCP server, generally available since 2026-02-17 (announced at Dreamforce October 2025) with expanded tools added 2026-05-13; it is the recommended replacement.

Last Evaluated: July 9, 2026
Official Website

Trust Vector Analysis

Dimension Breakdown

🚀Performance & Reliability
+
message delivery reliability

Message delivery success testing

Evidence
Slack API Documentation — High reliability for message posting and retrieval via Web API
highVerified: 2026-07-09
search accuracy

Search quality testing

Evidence
Slack Search API — Powerful message search with filters and context
highVerified: 2026-07-09
rate limit handling

Rate limiting behavior testing

Evidence
Slack Rate Limits — Tier-based rate limits (1+ requests per second), requires careful handling
mediumVerified: 2026-07-09
real time updates

Event delivery latency testing

Evidence
Slack Events API — Events API enables near real-time message notifications
mediumVerified: 2026-07-09
error recovery

Error handling testing

Evidence
Slack API Error Handling — Clear error codes with retry guidance
mediumVerified: 2026-07-09
🛡️Security
+
oauth security

Authentication security review

Evidence
Slack OAuth — Secure OAuth 2.0 with granular permission scopes
highVerified: 2026-07-09
message access risk

Access boundary testing

Evidence
Security Analysis — AI can read all messages in channels within granted scope
highVerified: 2026-07-09
posting control

Message posting capability testing

Evidence
Slack Permissions — AI can post messages as bot or user depending on scope
mediumVerified: 2026-07-09
data exfiltration risk

Data exposure analysis

Evidence
Data Flow Analysis — Workspace messages sent to LLM provider for processing
highVerified: 2026-07-09
audit logging

Audit capabilities review

Evidence
Slack Audit Logs — Enterprise Grid provides comprehensive audit logs
highVerified: 2026-07-09
🔒Privacy & Compliance
+
message exposure

Data exposure analysis

Evidence
MCP Data Flow — Slack messages including private conversations sent to LLM provider
highVerified: 2026-07-09
pii protection

Privacy controls assessment

Evidence
MCP Security Guidelines — No built-in PII detection or message content filtering
mediumVerified: 2026-07-09
workspace admin control

Enterprise control assessment

Evidence
Slack Admin Controls — Workspace admins can control app installations and permissions
highVerified: 2026-07-09
data retention

Data retention policy review

Evidence
Slack DLP — Slack retains messages per workspace policy, additional copies sent to LLM
mediumVerified: 2026-07-09
compliance readiness

Compliance framework review

Evidence
Slack Compliance — Slack is compliant, but third-party LLM sharing affects compliance posture
mediumVerified: 2026-07-09
👁️Trust & Transparency
+
documentation quality

Documentation completeness review

Evidence
Slack API Documentation — Comprehensive Slack API docs with examples and guides
highVerified: 2026-07-09
operation visibility

Operation traceability assessment

Evidence
Slack Activity — All API actions logged in audit logs and visible in channels
highVerified: 2026-07-09
permission transparency

Permission clarity assessment

Evidence
OAuth Scopes — Clear permission descriptions during OAuth flow
mediumVerified: 2026-07-09
mcp implementation

Implementation documentation review

Evidence
MCP servers-archived repository — Reference Slack server archived 2025-05-29; repository read-only, README states no security guarantees are provided for archived servers
Slack Developer Docs changelog — Slack's official MCP server reached general availability 2026-02-17, and additional tools (reactions, channel creation, member listing, file reading) shipped 2026-05-13; recommended replacement for the archived reference server
highVerified: 2026-07-09
⚙️Operational Excellence
+
ease of setup

Setup complexity assessment

Evidence
Slack App Setup — Requires Slack app creation and OAuth configuration
mediumVerified: 2026-07-09
api reliability

Uptime analysis

Evidence
Slack Status — High uptime and reliability (>99.9%)
highVerified: 2026-07-09
response time

Performance benchmarking

Evidence
API Performance — Good API response times (100-300ms typical)
mediumVerified: 2026-07-09
feature coverage

Feature completeness assessment

Evidence
MCP Slack Server — Covers basic message reading/posting, limited channel management
MCP servers-archived repository — Archived 2025-05-29; feature set frozen, no updates for Slack API or MCP specification changes
mediumVerified: 2026-07-09
cost

Cost analysis

Evidence
Slack API Pricing — Free for basic API usage, costs from Slack workspace subscription
highVerified: 2026-07-09
Strengths
  • +Powerful team communication and collaboration automation
  • +Comprehensive Slack API with rich feature set
  • +High reliability and uptime from Slack infrastructure
  • +Granular OAuth permission scopes for access control
  • +Excellent audit logging for Enterprise Grid customers
  • +Real-time message capabilities through Events API
Limitations
  • !Workspace messages exposed to LLM provider APIs
  • !No built-in content filtering or PII protection
  • !Risk of exposing confidential team communications
  • !Rate limits can be restrictive for high-volume operations
  • !ARCHIVED 2025-05-29: reference server unmaintained with no security guarantees; use Slack's official MCP server (GA February 2026) instead
  • !Compliance challenges when sharing workspace data with third parties
Metadata
license: Varies (Slack API proprietary, MCP implementation varies)
supported platforms
0: All platforms with OAuth support
programming languages
0: TypeScript
1: Python
2: Any language with Slack SDK
mcp version: 1.0
api provider: Slack Technologies
authentication: OAuth 2.0
api version: Slack Web API
rate limits: Tier-based (1+ requests per second)
first release: 2024-11
maintained by: None (Archived 2025-05-29)
repository: https://github.com/modelcontextprotocol/servers-archived
replacement: Official Slack MCP server (GA 2026-02-17, https://docs.slack.dev/changelog/2026/02/17/slack-mcp/)

Use Case Ratings

code generation

Useful for posting code snippets and updates, but limited for actual generation

customer support

Excellent for internal support channels and team communication automation

content creation

Good for collaborative content discussions, but not primary use case

data analysis

Useful for analyzing team communication patterns and sentiment

research assistant

Good for searching team knowledge and past discussions

legal compliance

Risk of exposing confidential team communications to LLM providers

healthcare

High risk if PHI discussed in Slack; compliance challenges

financial analysis

Risky for confidential financial discussions; requires careful controls

education

Great for classroom communication and student collaboration

creative writing

Useful for collaborative writing discussions but not primary tool