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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), yet the description adds substantial behavior: the ordered return of steps, the three notes, nearest stores, the card, the special 'restricted: true' path for controlled/age-restricted medicines, and the explicit 'not medical advice' disclaimer. That is real value beyond the structured fields.

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 one-line purpose before triggers, parameters, and returns, and it closes with a practical 'Next:' instruction. It is longer than strictly necessary and the parameter prose runs together, but nearly every sentence carries usable information.

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 tool with no output schema and no required parameters, the description fully describes the return payload (ordered steps, three notes, nearest stores, card, restricted flag) and covers 6 of 7 inputs, so an agent has everything needed to call and consume it correctly.

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 across 7 parameters, the description carries the full burden and does most of it: it defines chain as the destination chain with an explicit value list, explains drug (+strength/form/quantity) as adding that chain's card price with its date, and constrains zip as a 5-digit US ZIP passed only when supplied. Only locale is left undocumented.

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 first line states a specific action and resource: moving a prescription from its current pharmacy to the desired one. It is immediately distinguishable from price-comparison siblings like compare_prices and search_drugs, though it never names or contrasts with the closer siblings get_prescription_options or get_savings_card.

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 three concrete triggering conditions (prescription is at another pharmacy, user asks how to switch, user picked a chain while their prescription is elsewhere), which is strong 'when to use' guidance. It stops short of stating when not to use it or which alternative tool to pick instead.

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