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

Annotations already establish read-only, idempotent, non-destructive behavior. The description adds valuable contextual behavior: an unknown id is recoverable via near-miss ids named in the answer. This is meaningful beyond what the schema or annotations state.

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?

Three short sentences, each earning its place: what the tool returns, when to call it, and what to do on an unknown id. No filler, no repetition of annotated facts, and the main purpose is 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 single-parameter read-only tool with full schema coverage, annotations, and an output schema, this description gives the agent everything needed: trigger condition, return contents, and failure behavior. Nothing critical 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 coverage is 100%, and the schema already explains that id is returned by search, answer, get_topic, or get_related and is the last segment of the canonical URL. The description adds workflow context but no additional parameter-level meaning, so the 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 states a specific action ('Fetch one knowledge object by id') and names the resource plus its distinguishing contents (claims and cited sources). This makes it clear that get_entity is the id-based retrieval sibling among search, get_topic, and get_overview.

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?

It explicitly tells the agent when to use this tool: after search, answer, or get_topic has supplied an id. It also gives useful recovery guidance for unknown ids. It does not explicitly contrast get_entity with get_overview or get_related, so it stops short of full when-not instructions.

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