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

The readOnlyHint annotation already covers safety, and the description adds useful behavioral context about the aggregation: median, middle-half range, and retailer-to-retailer variation. It does not mention data recency, currency, or exact return structure, but for a read-only aggregation tool the description provides solid behavioral insight beyond the annotation.

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 two sentences and front-loads the core purpose and output metrics. The carat-size list is slightly redundant with the schema enum but is a convenient summary. Overall it is concise and well-structured, with minimal waste.

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?

The description provides a good high-level understanding of inputs and outputs, but with no output schema it leaves out return format details such as currency, units, and how the variation metric is represented. For an agent to fully interpret the result, more explicit output structure would be helpful.

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 schema has no parameter descriptions (0% coverage), but all five parameters are self-explanatory enums. The description identifies the spec dimensions and enumerates valid carat sizes, adding a little meaning beyond the schema, but it does not explain interpretation details like colour scale or origin values. This is adequate but not fully compensatory.

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 states that the tool returns typical market prices for a diamond spec across all tracked retailers, and lists the output metrics (median, middle-half range, variation). It is clear enough to distinguish from specific-diamond lookups, but it does not explicitly differentiate itself from the sibling 'market_overview' or name alternative tools.

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 implies the tool is for price checks on a specific spec rather than for individual diamond lookups or broad overviews, but it does not explicitly state when to use this tool versus siblings like 'get_diamond' or 'market_overview'. No exclusions or alternative conditions are provided.

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