members_get

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

Annotations already signal read-only, idempotent, non-destructive behavior. The description adds valuable context beyond that: optionality of fields (premium_since and pending absent when Discord omits them), the null possibility for joined_at, and the note about nick being raw data with human-readable text fencing. This is strong supplemental transparency.

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 well-structured with bolded sections for Purpose, When to use, and Returns. It is concise, front-loaded, and every sentence carries useful information without redundancy.

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?

For a simple two-parameter read-only fetch with rich annotations, output schema, and clear usage guidance, the description is complete enough. It covers what the tool does, when to use it, and important return-value nuances, leaving no significant gaps for tool selection or invocation.

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 100% for both parameters, with descriptions for user_id and guild_id. The description's mention of 'by user ID' reinforces the key parameter, but it does not add meaningful semantics beyond what the schema already provides.

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 states a specific verb and resource: 'Fetch a guild member by user ID.' This clearly distinguishes the tool from siblings like members_list and members_search, and the mention of inspecting roles, nick, and joined_at further clarifies its purpose.

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?

Provides a dedicated 'When to use' section: 'inspect roles, nick, joined-at of a known user.' This gives clear context, though it does not explicitly name alternatives or state when not to use it, so it falls short of a perfect 5.

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