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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds the credit cost model — 1 credit per call plus 1 per card and per include block — which is real operational context an agent cannot get from annotations. It omits failure handling for invalid or missing ids and does not say whether results preserve input order or how stale prices are.

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?

Two sentences, front-loaded with the resource and scope before the cost detail, with essentially no filler. The cost clause '+1 per card and include' is compressed to the point of being slightly ambiguous in grammar, costing a point.

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?

There is no output schema, and the description says 'current prices' without indicating how results are keyed back to the requested ids or what happens when some ids are invalid — an important gap for a batch tool where partial failure is likely. With only two well-documented parameters the tool is otherwise simple, so this is adequate but not complete.

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%, so the schema already documents the `sealed:{id}` prefix format with an example, and the description largely repeats it. The only added meaning is that `include` blocks are billed per card, which clarifies the cost tradeoff of the optional 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?

The description states a specific verb and resource ('current prices of up to 100 cards and sealed products'), plus the batching scope ('in one call') and the sealed-product id convention, which is enough to separate it from single-card siblings like get_card_prices or get_card. It stops short of naming those siblings explicitly, which keeps it from a 5.

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 phrase 'in one call' implies the intended use case — bulk lookups instead of repeated single-card calls — but no alternative tool is named and there is no stated when-not (e.g. use price history for trends, or compare_prices for side-by-side). Usage must be inferred from the sibling list rather than read from the description.

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