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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds the specific content returned (canonical facts, aliases, history, provenance) but does not disclose additional behaviors such as error handling, authentication requirements, or response structure. With annotations covering safety, this is adequate but not exceptional.

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, concise sentence that front-loads the action ('Read') and specifies the exact content. There is no waste or redundancy, and it is appropriately structured for quick comprehension.

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?

Given the tool's simplicity (one parameter, no output schema, annotations covering safety), the description is fairly complete. It lists the types of evidence returned, which gives the agent a clear expectation of the output. However, it does not specify behavior for missing entities or response format, which would be helpful but is not critical given the read-only, idempotent nature.

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 schema defines entityId as a required UUID with no additional description coverage (0%). The tool description does not mention entityId at all, nor does it explain how to obtain a valid entityId or what it represents. Since the schema does not compensate and the description does not either, this is a significant gap for a single-parameter tool.

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 ('Read') and identifies a clear resource ('canonical facts, aliases, history, and provenance for an entity'). This distinguishes it from siblings like read_recent_evidence_changes (focused on changes) and search_entities (search operation), making the tool's purpose unambiguous.

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. It does not mention read_recent_evidence_changes or search_entities, nor any conditions that would favor one tool over another. The agent is left to infer usage from the description alone.

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