Slack Get User Info

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, so the safety profile is covered, but the description adds nothing beyond that — no note on what fields are returned, lookup failure behavior for an unknown ID, or whether deactivated users are included. Given the low bar set by existing annotations, it still contributes essentially no extra behavioral context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence with zero padding, which is well-structured. It is arguably too terse rather than verbose, but there is no wasted text to penalize.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The output schema means return values needn't be explained, but with a sibling like slack_get_user_profile in the same namespace, the definition leaves the primary ambiguity unresolved. For a lookup tool in a crowded sibling set, it is not complete enough to guide correct selection.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With a single parameter and 100% schema description coverage, the schema fully documents user_id including its prefix format. The description adds no meaning beyond the schema, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ("Get information about a Slack user"), which is better than a tautology but adds no scope detail. Critically, it does not distinguish this tool from its close sibling slack_get_user_profile, so an agent cannot tell from the description which one returns profile-type data.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no guidance on when to use this tool versus slack_get_user_profile or slack_list_users. The single sentence provides no context, prerequisites, or exclusions, leaving routing entirely to inference from the tool name.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.