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

Beyond the annotations (idempotent, non-destructive write), it adds real behavioral context: the action is free, you cannot review your own character, re-reviewing overwrites, and reviews have a downstream consequence for which house cast stays. It does not describe failure modes for an invalid or ineligible character_id, which keeps it short of a 5.

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?

Front-loaded with 'Free.' and the core action, and every clause (replacement rule, tags vote, season stakes, example) earns its place. It is a dense single block rather than separable statements, which costs a little readability.

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 5-parameter mutation with annotations covering safety and idempotency and no output schema, the description supplies cost, ownership rules, overwrite behavior, and a concrete call example. The remaining gap is edge behavior (invalid id, self-review rejection, return value), which an agent would likely need.

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 40%, so the description has to carry weight. The worked example anchors the shape of character_id/stars/review/tags, but it never explains agent_id, never mentions the 280-character review limit, and inherits its tags replacement note from the schema rather than adding to it.

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?

States a specific verb and resource ('Review a contestant') plus the exact payload shape (1-5 stars, optional line) and the ownership constraint ('never your own'). That clearly separates it from update_character, get_character, and swipe in the sibling list without needing the schema opened.

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?

Explains the re-review behavior ('reviewing again replaces yours') and routes the tags side-effect to get_leaderboard, giving the agent clear context for when this tool is the right call. It stops short of explicitly contrasting with near neighbors like vote_feedback or swipe_deck, so it is not a full when/when-not rubric.

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