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

Annotations already cover the safety profile (read-only, idempotent, non-destructive), so the bar is lower. The description adds genuinely useful context beyond them: it requires a Carry Oracle key, and it is 'Raw data, not a call', which tells the agent not to treat the output as a recommendation. It does not describe return shape, but that gap is minor here.

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 dense sentences with no filler. The defining filter condition is front-loaded, and the routing rule comes last where an agent deciding between siblings will look for it.

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 single-parameter, no-output-schema read tool the definition covers what is needed: the filter semantics, the auth prerequisite, the nature of the output ('raw data'), and sibling routing. Only a brief note on the returned data shape is absent, which is acceptable given there is no output schema.

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 100%, and the single parameter is documented in the schema with its default of 0.5. The description restates the default (50%) and the threshold semantics, but adds no syntax or nuance beyond the schema, so baseline 3 applies.

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 resource (perps), a precise filter condition (|annualised funding| above a threshold, no hedge leg on Hyperliquid) and the mechanism (no spot, no same-ticker HIP-3 listing). It explicitly distinguishes itself from named siblings, so an agent can route correctly without opening a schema.

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 an explicit when-to-use case ('funding extremes that cannot be hedged on Hyperliquid') and names the alternatives for the excluded case (carry_xdex, carry_spot_perp). Both the positive and negative routing conditions are stated.

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