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

The annotations only declare readOnlyHint=true, but the description adds meaningful behavioral context beyond that: the leaderboard is scoped to a time span, is paginated, includes this account's own row via `me` when ranked, and lists the returned metrics. These behaviors are not merely restating the annotation and help the agent anticipate the tool's output and scope.

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?

Three sentences, each carrying distinct information: what the board contains, the `me` row behavior, and a pointer to the sibling tool for a simpler use case. The most critical facts are front-loaded in the first sentence. No redundant phrases or filler.

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?

Despite having no output schema, the description states the output columns, the pagination behavior, the available time spans, and the special `me` row. It also covers the main alternative tool, get_my_rank, which is the most likely source of confusion. Everything an agent needs to decide whether and how to call this tool is present.

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 input schema has 100% coverage, so every parameter is already documented with descriptions, defaults, and enums. The tool description does not need to repeat parameter details. It adds some conceptual context around the leaderboard shape but does not add meaning beyond the schema in a way that raises the score.

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 verb and resource: 'the trader PnL leaderboard for a time span'. It enumerates the exact fields returned (rank, username, address, PnL, ROI, current equity) and distinguishes this from get_my_rank by explicitly saying that the latter returns this account's rank across all time spans at once. An agent can understand exactly what get_leaderboard does without ambiguity.

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 description explicitly says to use the `search` filter for finding a trader by username or address, and directs the agent to `get_my_rank` when wanting this account's rank across all time spans at once. This provides clear when-to-use and when-not-to-use guidance relative to a direct sibling. The context is sufficient for an agent to choose the correct tool.

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