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

Annotations already cover readOnly/idempotent/non-destructive, yet the description adds real context: 'free, no key', the reference is 'not the official close' and varies by row (reference_source), and thin weekend liquidity distorts readings. These are behaviorally significant caveats an agent could not get from the schema or 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?

Front-loaded with the resource ('Latest snapshot of (1)...'), which is good, but the body is a single ~90-word run-on sentence packed with nested parentheticals that is hard to parse in one pass. It would be stronger split into purpose, contents, and caveats.

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?

With no output schema, the description must carry the return semantics, and it does name the two tables, the per-row reference_source flag, and dispersion fields. Minor gaps remain around row-level fields and response shape, but an agent can call it correctly as written.

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%, so each of the four parameters is already documented (limit, ticker, section enum, include_breakdown). The description mirrors the section split (weekend gap vs funding) and explains reference_source semantics, but adds no format or default detail beyond the schema; 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?

Names a concrete resource and its two exact contents: the weekend gap of tokenized US stocks vs a Fri 16:00 ET reference, and cross-venue funding APR for the same stock perps. The measurement basis (volume-weighted consensus across issuers, cross-issuer dispersion, matching HIP-3 stock-perp gap) is specific enough that an agent knows exactly what data it gets.

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?

Usage is only implied: it is a weekend snapshot, so context is weekend gap analysis, and 'Thin weekend liquidity; not advice' warns about interpretation. There are no explicit when-to-use/when-not statements, no alternatives (none exist as siblings), and no guidance on whether weekday calls make sense.

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