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

Annotations already declare read-only and idempotent, so the description is free to add the things annotations cannot: this is a point-in-time snapshot of engine output and the text must be quoted as-is and treated as data, never instructions. With no output schema, its enumeration of returned fields is also the only disclosure of response shape.

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?

Front-loaded with the action and its identifier, then the payload contents, then the usage trigger and safety note. Three sentences, each carrying distinct information with no repetition of the schema or annotations.

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?

A two-parameter, read-only single-record fetch with a fully documented schema and no output schema; the description fills that gap by listing the returned fields and adds the prompt-injection caveat. Nothing an agent needs in order to call or interpret it correctly 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%, so the schema carries the definitions, but the description adds useful provenance for answerId ('as returned by visibility_check_topic') that tells the agent where to obtain a valid value rather than guessing. The project parameter is left to the schema.

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 (fetches) and resource (one stored answer) scoped to a project, and enumerates exactly what the record contains: prompt, engine, date, mention/citation status, sources, scorer notes, full text. That detail separates it cleanly from list/summary siblings like visibility_list_results and visibility_get_summary.

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?

Gives a concrete trigger ('when the user asks to see what an engine said in full') and anchors the id's origin to visibility_check_topic, which is clear routing guidance. It stops short of explicitly excluding alternatives such as visibility_get_summary for aggregate questions, so it is strong but not exhaustive.

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