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

Annotations already establish read-only, idempotent, non-destructive behavior, and the description adds the economically important context: 'one request credit total' for the whole batch. It also discloses the response structure (per-line value, running USD total, ambiguous/not_found lists capped at 3 candidates), which is behavior an agent needs to reason about partial failures.

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, front-loaded with the core action and batch limit, then the per-line input rule, then the return/ambiguity behavior, then batching for oversized lists. No sentence is redundant and none restates the tool name.

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, yet the description still summarizes the shape of the response in one clause, which is helpful rather than duplicative. Combined with credit cost, batch ceiling, and ambiguity handling, an agent has everything needed to call this correctly and interpret partial results.

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 baseline is 3, but the description adds genuine resolution logic not encoded in the schema: id takes precedence and name is the fallback, with set/number/game narrowing the match. The cross-game disambiguation rationale for 'game' is useful context beyond the enum's own description.

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?

Opens with a specific verb and resource ('Price a list of up to 25 cards in one call') and scopes the batch size immediately. The batch-oriented framing clearly separates it from binderdex_get_card and binderdex_search_cards, which handle single-card lookups and discovery.

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?

Gives concrete operational guidance: use id when known, otherwise name plus set/number/game, and split lists longer than 25 into repeated batches. It also prescribes a workflow ('ask the user which card they meant before quoting a total') when results are ambiguous. It stops short of explicitly naming sibling tools as alternatives for single-card pricing, which keeps it off a 5.

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