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

With no annotations, the description carries the full burden and does reasonably well: it discloses that pricing is a fair price derived from comparing live marketplaces, that a miss returns suggestions rather than an error, and that every successful response contains a `url`. It omits anything on freshness/caching or rate limits, which keeps it short of a 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 tight sentences that lead with the core verb and resource, then move to input precision, error behavior, and output linkage. Minor redundancy: the market-name example duplicates the one already in the schema.

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 one-parameter read tool with no annotations and no output schema, the description covers input format, failure mode, and one key return field (`url`). It stops short of describing the price field itself or numeric formatting, leaving a small gap for an agent parsing the response.

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 100% and the parameter already documents the exact market hash name with an example, so the baseline is 3. The description reinforces the exactness requirement ('wear included') and adds miss behavior, but largely restates the schema example.

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 states a specific verb and resource — 'Current price in USD of one CS2 item' — and clarifies the pricing source (SteamAnalyst cross-market fair price rather than Steam Community Market alone). It does not name siblings, so an agent must infer on its own that price_history/compare_markets serve different needs.

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 implied by the single-item scope and the note that a miss returns suggestions, which hints at a fallback path. However, no alternative tool is named (e.g. search_items for resolving names, price_history for trends), and there is no explicit when-not-to-use guidance.

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