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

Annotations already establish readOnlyHint=true and openWorldHint=false, so safety is covered; the description then adds the substantive behavioral point — that coverage is bounded by this snapshot and that absence within it is not proof of nonexistence. It also discloses the shape of what comes back (sources, last-checked times, method), which tells the agent how to weigh freshness. No mention of pagination or size, but for a zero-argument metadata call that is a minor omission.

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 sentences, zero filler: the first enumerates returned fields, the second delivers the decision-relevant caveat. Content is front-loaded and every clause earns its place.

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 carries the burden of explaining what comes back, and it does so field by field (date, counts, venues, indices, events, sources, freshness, method). Combined with the absence-of-evidence caveat, an agent has everything needed to call it and interpret the result.

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 no parameters, so there is nothing for the description to disambiguate; the baseline of 4 applies. The description appropriately spends its words on return content instead of inventing parameter guidance.

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 enumerates exactly what the snapshot's coverage record contains — date, contract/venue/index/event counts, sources with last-checked timestamps, and method. That verb-less but content-specific framing clearly separates it from compute_list_prices, compute_market_events and search_compute_contracts, which return market data rather than metadata about the data. It stops short of a crisp 'returns the coverage manifest for…' opener, but the resource is unambiguous.

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?

'Use before concluding that a contract or event does not exist' gives a concrete trigger condition tied to a negative-existence inference, which is exactly the decision an agent needs help with. It does not name a sibling alternative or state when not to call it, keeping it below the top mark.

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