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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), and the description adds genuinely non-derivable behavior: output is vendor-reported with dates and explicit unknowns, no sponsored ordering or inferred fit percentages, and no vendor contact. Those trust and side-effect guarantees are exactly the context annotations cannot convey.

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, front-loaded with the core action and its constraints, followed by output expectations and non-goals. No filler or repetition of schema details.

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 read-only two-parameter tool with no output schema, the description covers the action, the input source, the result shape (evidence, dates, unknowns), and non-goals. The only residual gap is how topics affect the comparison output, which an agent must infer.

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?

With 0% schema description coverage the description must carry parameter meaning, and it does contribute two things the schema does not: the IDs must be distinct and must originate from find_emr_options. However, it says nothing about what the topic values mean or how multiple topics combine, leaving the enum list to speak for itself.

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 (compare), a bounded resource (2–4 distinct product IDs), a scoping axis (selected topics), and its provenance (from find_emr_options). An agent can distinguish it immediately from get_emr_evidence or get_pricing without opening a schema.

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 dependency on find_emr_options is stated explicitly, giving the agent a clear prerequisite for obtaining valid IDs. It also implies a boundary against get_pricing by declaring no inferred pricing, but it never explicitly says when to prefer get_emr_evidence or get_emr_vendor over this tool.

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