Check a batch of games against your account

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

Annotations already provide readOnlyHint and destructiveHint, so the safety profile is known. The description adds valuable behavioral detail beyond annotations: unmatched names are reported as not_found rather than failing the batch, and it lists exactly what information is returned (shelf, completion, rating, lists).

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, immediately front-loaded with the main purpose. It provides concrete details and a practical example without any filler. Every sentence 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 is simple: read-only batch lookup with two well-documented parameters. The description covers purpose, output items, and edge-case behavior (not_found). It does not explain the return format, but no output schema exists and the described items (shelf, completion, rating, lists) are sufficient for use.

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 has 100% coverage with descriptions for both parameters (games and include_lists). The description does not need to explain parameter mechanics in detail; it adds context about the included data (custom lists) but no significant additional semantics beyond what the schema already provides. Baseline 3 is appropriate.

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 the tool's function with specific detail: given a list of game names, report shelf, completion status, rating, and custom lists. It distinguishes itself from sibling tools by emphasizing the batch nature and the specific use case of checking many games at once against the user's account.

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 clear context for when to use this tool with the example 'here are 20 games, which do I already have?' and indicates it is built for batch checking. It does not explicitly mention alternatives or when not to use it, but the batch-oriented use case is clear enough to guide selection.

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