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

With no annotations, the description carries the burden and does disclose meaningful behavioral context: it reports holders with history and 'does not judge which canon is correct,' plus that layers are 'never merged.' That establishes a non-evaluative, read-style reporting posture, but it never states read-only nature, permissions, or return shape explicitly.

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?

Front-loaded with the core concept and the reporting purpose, then ends with the parameter instruction. The em-dash clause is dense but every part conveys scope or behavior; slightly verbose but no wasted 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?

For a single-optional-parameter, read-style tool with no output schema, the description adequately covers scope, reporting behavior, and parameter switching. It stops short of explaining return format or the meaning of the 'history' it reports, but nothing essential for invoking it is missing.

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?

There is one optional parameter with 0% schema coverage, so the description must compensate. It does explain the conditional meaning — passing 'book' yields one book's status, omitting it yields the overview — but gives no hint of expected format (name, abbreviation, ID) for the book value.

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 gives a specific resource (the canon) and a clear verb (REPORTS who holds what), framing it as concentric layers of the undisputed 66 plus tradition-specific books. It's distinguishable from vague siblings like lookup or define, though it never explicitly names a sibling it contrasts with.

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 gives one piece of usage guidance — 'Pass book for one book's status; else the overview' — which tells the agent when to use the parameter. However, it offers no exclusions or alternatives among the many adjacent tools (cross_references, commentary, original_words), leaving routing to inference.

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