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

With no annotations, the description carries the full burden, and it does disclose the pricing methodology (0.75 in + 0.25 out) and that capability scores appear only 'where matched' — real behavioral detail. It does not state that this is a read-only snapshot, whether results are cached or refreshed when, or what happens for models without an Epoch match beyond the vague qualifier.

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 lines, front-loaded with scope ('Every model priced in this week's index') followed by the returned fields, with no filler. The terseness is close to cryptic in places ('blended $/1M (0.75 in + 0.25 out)'), but every clause carries information.

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 and no annotations, the description does the necessary work of enumerating the returned fields and the price-blend formula. Given a zero-parameter read-only listing, the remaining gaps (freshness semantics, unmatched-model handling) are minor rather than blocking.

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 tool takes zero parameters, so the schema has nothing to document and the baseline is 4. The description's only parameter-adjacent content — the blend weights — describes output computation rather than inputs, which is fine given there are none.

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 makes the opaque name 'basket' concrete: it returns every model in this week's list-price index with provider, blended $/1M, and Epoch capability score. That is a specific resource with stated contents. It does not, however, distinguish itself from siblings like index_latest or model_price, which an agent must guess between.

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?

There is no statement of when to use this versus index_latest, index_catalogue, or model_price, and no exclusions or prerequisites. The agent must infer from the name and field list that this is a full-universe snapshot rather than a lookup or a series.

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