get_user_profile

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description does add one genuinely non-obvious behavioral fact not present in structured data: the result is cached per instance, warning the agent that the value may be stale. It does not cover return shape or staleness lifetime, so it is a modest add-on rather than rich disclosure.

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?

It is short with no filler, which is good, but it is a single semicolon-joined fragment that leads with an implementation detail (caching) rather than a front-loaded statement of what the tool returns. Brevity here shades into under-specification rather than efficiency.

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?

There is no output schema, so the description carries the full burden of explaining the return value, and it only obliquely implies the display name is returned without listing any other profile fields. For a read tool with numerous near-duplicate siblings and no structured output contract, the description is too thin for an agent to call it confidently.

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?

The tool takes zero parameters and the schema is fully closed (additionalProperties: false, 100% coverage), so there is nothing for the description to disambiguate. Baseline 4 applies; no parameter semantics are missing.

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 never states what the tool does. 'Cached per instance; every date-scoped endpoint needs the display name' only hints that a display name is the payload and that the result is cached; it does not say 'returns the authenticated user's profile.' An agent must infer the verb and resource from the tool name alone, and the presence of siblings like display_name, full_name, user_name and get_userprofile_settings makes that inference riskier.

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 a faint usage cue ('every date-scoped endpoint needs the display name'), which suggests when the value is consumed, but no explicit when-to-call guidance and no differentiation from the many overlapping siblings (display_name, full_name, user_name, get_user_settings, get_user_summary). The agent is left to guess whether this or a sibling is the right lookup.

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