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

No annotations are provided, so the description carries the behavioral burden. It indicates a read-only lookup and the key returned fields, but it does not describe data source, date-window boundaries, error handling, or behavior when no pharmacies are found. The schema provides the published-window detail, but the description itself adds little beyond the obvious get operation.

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 a single front-loaded sentence that states the operation, scope, temporal condition, and expected output fields with no filler or redundancy. Every phrase contributes to the agent's understanding.

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?

This is a simple two-optional-parameter read tool with no output schema, and the description names the essential return fields (address, phone). The schema covers date format and locality behavior. Missing details such as invalid-date handling or empty-result behavior are minor given the low complexity.

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?

The input schema already documents both parameters with 100% coverage: date format/default behavior and optional locality filter. The description only echoes 'date' and Luxembourg, adding no semantic detail beyond what the schema already provides.

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 uses a specific verb ('Get') and resource ('pharmacies on duty'), with clear geographic scope ('in Luxembourg'), temporal scope ('for a date'), and expected return fields ('address and phone number'). It is clearly distinguishable from all sibling tools, none of which target pharmacies.

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 description states the operational context: retrieving duty pharmacies for a specific date in Luxembourg, with an optional locality filter implied by the schema. It does not explicitly mention exclusions or alternatives, but no pharmacy-specific sibling exists, so the context is sufficient for an agent to select it.

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