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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real value beyond that by scoping the payload and explicitly excluding stock and medicine prices, preventing false expectations about availability data. It does not discuss not-found behavior, which is the main remaining gap.

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?

Two compact clauses plus a one-line example; the payload contents come first, the negative scope second, and the call example last. No filler words and nothing restating the title redundantly.

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?

With an output schema present, the description need not document return values, yet it usefully previews them; the single parameter is fully specified by schema plus example. The only missing element is failure behavior for a nonexistent slug, which matters for a lookup tool driven by user-supplied identifiers.

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%: the single slug parameter has a description, a regex pattern, and length bounds, so the schema already carries the burden. The inline example {"slug":"city-pharmacy"} illustrates a realistic slug shape but largely restates what the pattern conveys, so this is baseline-level added meaning.

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 retrieval verb and resource ('One pharmacy in full') and enumerates the payload contents (address, hours, delivery options, GPhC record, partner clinics, FAQs). The 'in full' framing implicitly contrasts with the list-style sibling find_pharmacies, but it never names that sibling, so differentiation is inferred rather than explicit.

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 slug-keyed example and 'one pharmacy' phrasing imply the lookup-by-identifier use case, and 'Never stock or medicine prices' sets a scope boundary. However, there is no explicit instruction on when to reach for this vs find_pharmacies or compare_providers, and no note on what happens with an unknown slug.

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