resolve_users

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

The readOnlyHint annotation already declares this as a safe read operation. The description adds minimal behavioral context beyond this - it explains what the tool does (resolves ids to display names) but doesn't mention edge cases like unknown/invalid ids, batch limits, or format of the output. With annotations covering the read-only nature, a modest score is appropriate since the description adds only marginal value.

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?

The description is compact - one functional sentence plus a brief parameter note. It's efficient with no filler, though putting the Args detail in the description duplicates what the schema already provides (a small redundancy). The core message is front-loaded and clear.

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 tool has a single simple parameter with 100% schema coverage (user_ids is the only param and it's mandatory). An output schema exists. For such a simple one-parameter, read-only utility, the description adequately covers what's needed - resolve ids to display names. There's an output schema to describe return structure, and the operation is straightforward. Not much more is needed for this simplicity level.

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?

Schema coverage is 0% for the parameter description, but there's only one parameter (user_ids) and the tool description itself explicitly explains its meaning ('List of Slack user ids to resolve') and even gives an example format ('U0123'). The description fully compensates for the 0% schema coverage on this single, self-explanatory parameter.

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?

The description uses a specific verb+resource pattern: 'Resolve Slack user ids to display names.' This clearly states what the tool does and what its output is (display names). Among siblings like search_messages, read_thread, and list_channels, this purpose is clearly distinct - none of the other tools resolve ids to names. It's immediately clear what this tool is for.

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?

The description implies when to use it (when you have Slack user ids and need display names) but doesn't explicitly discuss when NOT to use it or how it contrasts with alternatives. The sibling tools have clearly different functions, so confusion risk is low, but there's no explicit guidance on context or exclusions. This is adequate but not richly developed.

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