entity

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

With no annotations, the description carries the full burden. It does disclose a key behavioral trait—exact-name lookup returning details or null on miss—which implies read-only and non-exhaustive matching, but says nothing about matching semantics (case sensitivity, fuzzy vs exact, ambiguity handling) or auth.

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, zero filler, with the action and the return behavior both front-loaded.

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 single-parameter read with no output schema, stating 'returns entity details or null' covers the essential contract. However, the vague tool name 'entity' and the unresolved question of how this differs from sibling retrieval tools leave real gaps for an agent choosing a tool.

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 coverage is 100% and there is only one parameter already documented as 'Entity name or alias to look up'. The description echoes 'name or alias' without adding format or resolution rules, so baseline 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?

States a specific verb plus resource ('Look up an entity') and even enumerates what counts as an entity (person, project, concept). It does not differentiate from sibling tools like search or facts, so an agent can't tell from the description alone which lookup path to take.

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 indication of when to use this versus 'search', 'facts', or 'keyword', which all plausibly retrieve related information. The only implied usage is 'you have a name', which is thin.

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