Slack

Slack's Web API supports field selection and pagination, but responses can be verbose with nested user/channel objects that agents must filter; no explicit batching endpoint for bulk operations limits efficiency.

Slack offers comprehensive REST API access, multiple official SDKs (Node.js, Python), and a detailed developer platform, though the absence of an MCP server and GraphQL API prevents a higher score.

Slack supports both OAuth 2.0 with granular scopes and bot tokens for autonomous operation; API keys and app-level tokens enable straightforward agent authentication without human intervention.

Slack publishes rate limits (60 requests per minute for most endpoints) and supports some conditional requests, but no ETags or caching directives are documented, and latency data is unavailable.

Slack provides excellent documentation and a published llms.txt file signaling AI-agent awareness, but lacks an OpenAPI/Swagger spec and relies on web documentation rather than machine-readable schema.

Slack maintains API versioning and consistent response schemas, with a public status page, though explicit idempotency key support is not clearly documented for all write operations.

Slack offers scoped OAuth permissions and test workspaces for development, but lacks explicit dry-run modes or operation-level undo capabilities; token revocation is the primary safety mechanism.

Slack provides webhooks (both incoming and outgoing) and event subscriptions for real-time updates, enabling reactive agent workflows, though streaming APIs are not available.