full_name

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds one genuinely useful behavioral fact beyond that: the value comes from a cached profile, implying it may be stale and that no network fetch is involved. It stops there, giving no detail on null/empty behavior.

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 clause, no filler, no repetition of the tool name. Every element ('account holder's', 'full name', 'cached user profile') earns its place.

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 no-argument read with an explicit safety annotation, the description plus annotations cover nearly everything needed to invoke it. The remaining gap is disambiguation from 'display_name' and 'user_name', which live in the usage-guidelines dimension but also affect a complete picture of this tool's role.

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, so the baseline of 4 applies; there is no parameter surface the description needs to compensate for. It correctly avoids inventing argument behaviour it does not have.

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 resource and provenance for a zero-param getter: the account holder's full name from the cached profile. That is unambiguous about what it returns. It does not, however, distinguish itself from sibling tools like 'display_name', 'user_name', or 'get_user_profile', which an agent would need to choose between.

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 when-to-use guidance, no condition under which this is preferable to 'display_name' or 'user_name', and no mention of what it returns if the profile is empty. The agent must infer selection purely from the near-identical sibling names.

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