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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is known. The description adds mention of return fields, but these are also covered by the existing output schema, so it adds limited new behavioral context. No contradiction exists, but the description doesn't go beyond what annotations + schema already establish.

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 with zero filler. The first sentence states the core purpose and the key return fields; the second gives the sibling routing. Front-loaded and efficient, every word 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?

The tool has a full output schema, complete parameter descriptions, and annotations covering safety. The description ties it together by clarifying purpose, return contents, and sibling relationships. Nothing an agent needs to decide whether to call this tool or interpret its results 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?

Schema description coverage is 100% – every parameter (author_id, limit, offset) has a clear description. The tool description adds no additional parameter-specific meaning beyond what the schema already provides, so the baseline of 3 applies.

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 opens with a specific verb and resource: 'List works by an author.' It also names the exact return fields (titles, cover IDs, work OLIDs) and explicitly differentiates from sibling tools (openlibrary_get_author, openlibrary_get_editions). This leaves no ambiguity about what the tool does or how it differs from its neighbors.

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 gives explicit routing guidance: 'Use openlibrary_get_author for author bio and details, or openlibrary_get_editions to explore specific printings.' This clearly tells the agent when NOT to use this tool and points to the correct alternative, which is exactly what usage guidelines should provide.

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