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

Annotations already declare this read-only and non-destructive. The description adds useful behavioral context: with no filters it returns the first page, and query/tag act as substrings that can be combined. No contradiction with annotations exists.

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?

A single front-loaded sentence communicates the action, resource, filters, and default behavior without any filler. Every phrase earns its place.

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 simple optional-parameter search tool with a full output schema and safety annotations, the description covers the key default behavior and filter combinations well. It does not explain pagination beyond 'first page' or how an agent would request later pages, which is a minor 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?

The input schema already documents all three parameters with clear case-insensitive substring semantics, limit bounds, and defaults. The description only lightly echoes that query relates to title/author and tag to property tag, adding no meaningful syntax or format details beyond the schema.

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?

States a specific action, 'Search or list', on a clearly defined resource, Penwright's writing-craft book library, with explicit filter dimensions (title/author substring and property tag). This distinguishes it from the sibling get_* tools, which retrieve specific items rather than searching or listing.

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 implies the tool is for browsing or filtering the library, and it notes the no-filter default behavior. However, it never explicitly says when to use this tool over the sibling get_* tools or when to prefer direct retrieval, leaving the usage decision mostly to inference.

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