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

With no annotations, the description carries the full load and does real work: it discloses the data sources (CSFloat, Chinese venues), that turnover values are in USD cents, the auth tier requirement, and that every successful answer contains a `url` to the item's SteamAnalyst page with an instruction to link it when citing. Missing only error/failure behavior and rate limits, which keeps it below 5.

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 sentences, no filler: what it returns first, then the access prerequisite, then the citation requirement for the returned url. Each sentence carries information an agent needs to call or report the result correctly.

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?

No output schema exists, so the description must describe returns — and it does, naming each metric and the unit (USD cents) plus the url field. Combined with a fully documented 2-param schema, an agent has enough to call it and cite results. Absent failure-mode or coverage caveats (e.g., what happens for items with no sales) keep it from 5.

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 both `days` (range, default 30) and `market_name` (exact hash name, route to search_items for loose names) are already fully documented in the schema. The description adds nothing about either parameter. Baseline 3 is appropriate.

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 verb and resource: sales volume for one CS2 item, with the exact metrics per venue (daily sales count + average price on CSFloat; trade count + turnover on Chinese venues). An agent can tell this is a liquidity/volume lookup rather than a plain price lookup. It does not name a sibling like price_history or get_price, so differentiation is inferred from the metrics listed rather than stated.

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: an agent infers it should call this when it needs sales counts or turnover rather than a spot price. There is no explicit when-to-use/when-not or routing to compare_markets, price_history, or get_price. The one concrete prerequisite — an Ultimate-tier API key — is stated, which is useful but is access guidance, not tool selection guidance.

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