lookup_unit

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

With no annotations, the description carries full responsibility for behavioral disclosure. It states what is returned but does not clarify whether the operation is read-only, requires any permissions, or has rate limits. The absence of any behavioral hints (e.g., 'This is a read-only operation') leaves the agent with insufficient understanding of side effects or constraints.

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 a single sentence, concise and front-loaded with the action and main resource. Every word contributes meaning, and there is no fluff or redundancy. It efficiently communicates the core purpose.

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 lookup with three parameters and no output schema, the description adequately covers the tool's purpose and return content. However, it omits details such as the default value for 'game_mode' ('40k'), whether the lookup supports fuzzy matching, and if it returns a single result or multiple. These gaps reduce completeness.

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%, so the baseline is 3. The tool description does not add any extra meaning beyond what is already in the schema parameters. For example, the description of 'unit_name' as 'Name or partial name' is already present in the schema. No additional usage tips or format expectations are provided.

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 looks up a Warhammer 40K unit or Kill Team operative by name and returns stats, weapons, abilities, and keywords. It uses a specific verb ('Look up') and resource ('datasheet'), making the purpose obvious. While it doesn't explicitly distinguish from the sibling 'search_units', the uniqueness is implied by focusing on single datasheet retrieval rather than search 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?

No guidance is provided on when to use this tool versus alternatives like 'search_units' or other lookup tools. There is no mention of prerequisites, typical use cases, or scenarios where this tool would be inappropriate. The agent is left to infer usage from the tool name and description.

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