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

Annotations already mark it readOnly/idempotent/non-destructive, and the description adds useful output behavior: up to eight matches, dated card-price starts, and foreign-brand matches. This goes beyond the annotation set, though it omits details such as locale handling.

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 short and front-loaded: purpose first, then result details, then caller restriction. The line break after the em dash is slightly awkward, but there is no wasted wording.

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 an internal UI suggest tool with no output schema, the description communicates the result count and key result content. Locale behavior and matching semantics are absent, so it is not fully self-contained for an agent.

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 0%, so the description must explain parameters; it does clarify q as the text the person is typing. The locale parameter is never mentioned, and no format or constraints are provided, leaving a gap.

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 clearly identifies a specific behavior: returning medicines matching the text typed into FineRx search, and it notes who calls it ('called by the card itself'). It does not explicitly contrast with sibling ui_* tools, which keeps it from a 5.

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 provides a clear exclusion ('Not for the model') and a clear caller context ('called by the card itself'), telling an agent that this is a UI-internal tool rather than an API to choose directly. It names no alternative tool, so it earns 4 rather than 5.

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