Favorite person

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

Annotations already declare readOnlyHint=false, destructiveHint=false, and idempotentHint=true, so the safety profile is covered. The description adds one piece of genuinely new context — that a tier-based limit gates the operation — but it does not say what happens when the limit is hit, nor does it acknowledge the idempotent behavior for an already-favorited person.

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 no filler. The mutation and its gating constraint are both stated immediately, and nothing redundant is included.

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 two-parameter mutation with full schema coverage and an annotation set covering safety, this is close to adequate. The remaining gap is the tier-based limit: the description raises the constraint but leaves the agent without a way to know the limit or predict the failure, and there is no output schema to clarify what the favorite record looks like.

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 description coverage is 100% for both parameters (tmdb_id as TMDb person ID, role as an actor/director enum defaulting to actor), so the schema carries the semantics. The description adds nothing about either parameter — notably it never clarifies why role matters or how it interacts with the favorite entry.

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 gives a specific verb and resource ('Add a person to the user's favorites') that an agent can match against the directionally opposite siblings unfavorite_person and get_favorite_people. It stops short of naming those siblings, but the add/remove/list triad is unambiguous from the verb.

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 explicit when-to-use or when-not-to-use guidance; the only conditional information is the parenthetical tier-based limit, which is a constraint rather than a routing rule. An agent must infer from the name that this is the write counterpart to unfavorite_person and that get_favorite_people should be used to check existing favorites.

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