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

Annotations already declare readOnly/idempotent/non-destructive, and the description still adds meaningful behavior: the address is resolved from the token rather than passed in, ledger data is restricted to non-funding updates, start_time defaults to 30 days ago, each answer names the wallet and address read, and the response carries app_url. That is rich context beyond the structured fields.

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 the resource and then walks the views in order; nearly every clause carries information, though the long em-dash sentence listing view=portfolio ranges is dense and could be broken up. Size is justified by a five-view discriminating tool.

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-required-param, five-mode tool with no output schema, the description covers mode selection, defaults, wallet resolution, and return provenance. An agent has everything needed to pick a view and call it correctly.

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 only 50% (only the two timestamps are documented), but the description compensates fully: it explains all five view enum values, the meaning of wallet=main vs wallet=agent, the epoch-ms format and 30-day default for start_time/end_time. An agent can invoke this correctly without opening the schema.

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+resource (Hyperliquid account performance/facts) and enumerates the five views with distinct semantics, so an agent knows exactly which sub-answer each view returns. It explicitly distinguishes itself from siblings by pointing to get_positions / get_account_balances for positions and balances.

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?

Gives explicit when-to-use guidance per view (e.g. view=portfolio is 'the call for "how is my portfolio doing"'), states the default view, and routes the agent to alternatives for open positions/balances. The wallet parameter's trade-off (main vs agent deposit wallet) is also spelled out.

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