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

With no annotations to lean on, the description carries the full burden and does disclose a significant operational trait: inputs are frozen since 2026-09-07, the USD series stopped, and responses carry usd_panel {frozen: true, as_of}. It even prescribes response phrasing ('Say "last published", never "today"'). It stops short of permissions, rate limits, or error behavior.

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?

The critical frozen-data caveat is front-loaded, which is the right call for a stale-data warning. There is mild redundancy between 'Get the latest market price and historical price data' and 'Returns current market price, low (buy-it-now) price, and daily price history', but the block is otherwise tight.

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?

An output schema exists, so return-value documentation is optional, yet the description still usefully sketches the returned fields and flags the frozen-data envelope. The main omission is any guidance on choosing between the two input modes when both or neither are supplied (no required params).

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 each parameter already documents itself, so the baseline is 3. The description's 'fuzzy search' vs 'exact lookup' distinction largely restates the schema descriptions, and the `days` window parameter is not mentioned in prose at all.

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 names a specific verb and resource ('Get the latest market price and historical price data for a trading card') and identifies the two input modes. It fails to differentiate from close siblings like get_market_snapshot or simulate_price, so an agent must infer which of these price-related tools is the right one.

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?

It tells the agent how to invoke it ('Provide either a card name (fuzzy search) or a TCGPlayer product ID') but gives no when-to-use/when-not guidance relative to get_market_snapshot, get_forecast, or simulate_price. Usage is implied rather than contrasted with alternatives.

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