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

Annotations already mark the tool as read-only, idempotent, open-world, and non-destructive. The description adds valuable non-obvious behavior: it costs 0.02 USDC via x402, returns a decision plus purchase routing, and incorporates multiple signal types. No contradiction with annotations.

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, each contributing distinct information: the core output, the purchase-routing behavior and cost, and the triggering user intent. It is front-loaded and free of 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?

The description covers purpose, inputs, cost, and when to use the tool, and an output schema exists so return values need not be spelled out. It is nearly complete, though it could briefly state that raw market/rarity/authenticity details belong to sibling tools.

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 67%, with id, query, and lang already described in the schema. The description mentions analytical inputs (price, MSRP, rarity, authenticity) but does not add detailed meaning for the actual parameters beyond what the schema provides, so a 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?

The description states a specific output ('Return BUY, WAIT, WATCH or AVOID') for a clearly bounded resource ('an identified anime collectible'). This distinguishes it from sibling tools like anime_market or anime_rarity, which provide raw data rather than a recommendation.

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 gives an explicit trigger: 'Use when the user asks whether to buy now, wait for a lower price, watch the market or avoid the item.' It does not explicitly list when not to use it or name alternative sibling tools, but the use case is clear.

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