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

No annotations are provided, so the description carries the full burden. It correctly implies a read-only operation (re-resolving) and declares the output fields. However, it does not mention any side effects, error cases, or other behavioral traits that might affect agent decision-making.

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?

The description is two sentences, front-loads the purpose and usage, and contains no superfluous information.

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?

Given the tool's simplicity (2 params, no output schema), the description adequately covers what the tool does and what it returns. It does not elaborate on potential error states, but for a straightforward lookup this is sufficient.

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 covers both parameters (100% coverage), so the baseline is 3. The description adds value by specifying that the handle comes from a search_books result and that utm_source defaults to 'mcp', which aids the agent in usage.

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 clearly states a specific verb ('re-resolve') and resource ('book') and enumerates the returned data (purchase URL, cover image, ISBN). It also distinguishes itself from the sibling tool 'search_books' by noting that it refreshes a known handle without re-running a full search.

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 explicitly says when to use the tool ('to refresh or re-reference a book across turns') and implies when not to use it (when you already have the handle, avoid the full name search). It does not provide explicit exclusions or mention alternative tools beyond the implied contrast.

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