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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety is covered. Beyond that, the description discloses the full outcome set (current, out_of_date with the current edition and what changed since, not_found) and adds a meaningful limit: a match identifies the edition a code names but does not prove a copy is authentic. That qualification is real behavioral context an agent would otherwise misread as a verification guarantee.

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, no filler. The subject, the input format, and the possible results are front-loaded, and the authenticity caveat is placed last where it reads as a qualification rather than a distraction.

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?

This is a single-parameter read tool with an output schema, so the description does not need to document return structure. It covers input meaning, result states, and the key interpretive caveat; only the absence of sibling routing guidance leaves a small gap.

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 0%, so the description carries the parameter burden, and it does: the single argument is described as the 8 characters printed on a copy of the book, with a formatted example. It does not mention case sensitivity or how to handle malformed input, which keeps it below a 5.

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 (check) and resource (an edition code) and pins down exactly what an edition code is: the 8 characters printed on a copy of a Rolling Edition book, with a concrete example (483B-Z9SS). It also enumerates the three outcomes, so an agent can tell this apart from get_contents or search_books without consulting the schema.

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?

Implicit usage is clear from the framing: the caller has a physical code in hand and wants to validate it. However, no sibling tool is named and no explicit when-not condition is given, so an agent must infer that this tool is for code lookup while search_books and get_contents cover other discovery paths.

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