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

Annotations already indicate readOnlyHint=true, and the description adds meaningful behavior beyond that: it uses a single premiumIndex call without a symbol rather than looping per-pair, and it ranks pairs into crowded long/short buckets. This is useful operational context not present in annotations or schema.

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 dense sentences, each earning its place: purpose/scope first, implementation detail second, sibling contrast and threshold third. No fluff or repetition.

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?

Without an output schema, the description explains the key return concept (ranked crowded long/short pairs) and all behavioral caveats (single call, all pairs, threshold). It does not specify exact output fields, but the agent can select and invoke the tool correctly with the information given.

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 100%: both limit and quoteFilter are fully described with defaults, ranges, and meaning. The description itself adds no param-specific information beyond tool-level context, so it stays at the baseline for a fully schema-documented tool.

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?

Description uses a specific verb + resource + scope: it scans funding rates for ALL pairs at once via one premiumIndex call, then ranks crowded long and short pairs. It also explicitly distinguishes itself from sibling binance_get_funding_rate, which requires a specific symbol.

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?

Explicitly names the alternative tool (binance_get_funding_rate) and explains the difference: this tool scans all pairs, the sibling needs a specific symbol. It also clarifies the crowd threshold (±0.03%), giving concrete selection criteria.

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