lookup_unit

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

With no annotations, the description carries the full burden of behavioral disclosure. It does state that the tool returns stats, weapons, abilities, and keywords, but it does not mention matching behavior (exact vs partial), handling of multiple matches, error cases, or whether the operation is read-only. Some behavioral transparency is added, but key details are missing.

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-loaded with the action verb, and contains no filler. Every word contributes to understanding the tool's purpose and output.

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 tool, the description covers the core purpose and return content, and the schema covers parameters. However, with no output schema, it does not clarify behavior on partial matches or ambiguous results, leaving a minor completeness gap. Overall, it is mostly complete but could be slightly more explicit about match handling.

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% parameter description coverage, so the description does not need to explain parameters. It also does not add any additional parameter semantics, such as examples or parameter interactions, so the baseline of 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 uses a specific verb ('Look up') and identifies a clear resource (Warhammer 40K unit or Kill Team operative datasheet). It also lists the return content (stats, weapons, abilities, keywords), distinguishing it from sibling tools like search_units (search vs direct lookup) and compare_units (comparison).

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 usage when you have a unit name, but does not explicitly state when to use this tool versus search_units or compare_units. No exclusions or alternative tool recommendations are provided, leaving the usage context implied rather than explicit.

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