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

Annotations already mark the tool as read-only and non-destructive. The description adds useful behavioral context: it returns only summary data, does not include full healing properties, and uses GIA-authoritative assignments. This goes beyond the structured annotations.

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 primary action is front-loaded in the first sentence, and the rest is compact and relevant. The use-case sentence is slightly promotional but adds helpful context without redundancy.

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 simple read-only tool with one required parameter and rich schema descriptions, the description sufficiently explains the purpose, the summary nature of the response, and where to go for more detail. The exact fields in the summary are not enumerated, but this is adequately low-stakes for inference.

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 description coverage is 100%, and the input schema already documents the month range, language enum/default, and compact flag behavior. The description adds no parameter-level detail, so the baseline of 3 is appropriate.

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 states a specific verb and resource: 'Get the traditional birthstone crystals for a given birth month.' It clearly distinguishes from sibling tools by the month-based birthstone scope, and it clarifies that only summary data is returned.

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 names concrete use cases such as birthday gift recommendations and personalized crystal suggestions, and it explicitly directs agents to the detail endpoint for full healing properties. It does not explicitly compare against sibling tools like get_crystals_zodiac_sign or get_crystals_search, but the month-focused scope makes the intended usage clear.

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