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

With no annotations, the description carries the full burden and does useful work: it discloses the auth requirement (Ultimate-tier API key), the currency/unit (USD cents), the data sources, and that a successful response includes a SteamAnalyst `url` to cite. It stops short of describing response shape or error behavior, but is substantially more transparent than a bare data-fetch description.

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 short sentences, front-loaded with purpose, then auth, then output/citation guidance. Every sentence adds value and there is no filler.

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 two-parameter read tool with no output schema, the description covers what is returned (SteamAnalyst fair price, BUFF ask/bid, OHLC on Chinese venues, in USD cents), auth, and the `url` field. It does not fully describe the daily series structure or edge cases, but is otherwise complete enough to call correctly.

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%, and the schema already explains `market_name` as an exact Steam hash name with a search_items fallback and `days` as default 30 with bounds. The description adds only the 'one CS2 item' framing and does not add parameter-level detail beyond the schema.

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 (daily price history), scope (one CS2 item), and the exact metrics returned. The 'one CS2 item' scope implicitly separates it from multi-item tools like compare_markets, but no sibling is named explicitly.

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?

The description implies this is the historical single-item lookup, but it never explicitly contrasts it with get_price, compare_markets, or float_prices. The Ultimate-tier API key requirement is stated, but there is no 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.