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

Annotations already establish read-only, idempotent, non-destructive behavior, so the description only needs to add non-obvious context. It adds that an agent key is required and that the result is scoped to the caller's entries, which is useful behavioral information beyond the annotations.

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?

Two short sentences with no filler; the user scope is front-loaded and the returned fields are compactly enumerated. The auth requirement is stated in a separate concise sentence.

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 zero-parameter read-only tool, the description completely covers what data is returned and the access requirement. No output schema exists, but the field list fills that gap adequately, and the annotations cover the safety profile.

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 schema leaves nothing undocumented and the description has no parameter definitions to compensate for. Baseline 4 applies, and the description's mention of the returned sub-book fields provides usable context even though params are absent.

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 identifies a specific resource ('your competition entries') and enumerates the returned fields (cash, realized P&L, open positions, order count), which distinguishes it from sibling tools like list_competitions and get_competition_leaderboard. However, it is a noun phrase with no explicit verb like 'list' or 'get', so the action is implied from the title and context rather than fully stated.

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?

The 'YOUR' scoping and sub-book field list make clear this is for the caller's own competition data rather than general competition listings, and 'Agent key required' states a prerequisite. It does not explicitly name when to prefer a sibling like list_competitions or get_my_portfolio, but the context is clear enough to guide selection.

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