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

With no annotations, the description carries the full behavioral burden but only partly meets it. It usefully discloses the result cap and ordering ('Up to 500 newest') and the shape of each record, but says nothing about currency, what happens if the card is not found, or how 'newest' interacts with the days filter.

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 tight sentences with zero waste: the first front-loads what the records contain, the second front-loads the limits and filters. Nothing is repeated from the schema and no filler appears.

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 tool with no annotations, no output schema, and 0% schema description coverage, the description should resolve more. It handles the return record shape and result cap well, but leaves the required 'card' identifier and the semantics of days (default window, max 1095) undocumented anywhere.

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 0%, so the description must compensate and it does so only partly. It meaningfully clarifies grade with concrete examples ('PSA 10', 'RAW') and explains days as a lookback filter, but the sole required parameter, 'card', is never explained — an agent cannot tell whether it expects an ID, a name, or a slug.

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 (completed sales for a card) and enumerates the fields returned (date, price, grader/grade, platform, listing title), which is much more informative than the bare name. It implies a distinction from aggregated siblings like get_price_history by framing these as individual completed transactions, but never names an alternative outright.

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: 'the completed sales behind a price' suggests an agent should reach for this when it wants raw comps rather than an aggregate. There is no explicit when-not guidance and no mention of the sibling tools (get_price_history, get_deals) that an agent must choose between.

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