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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description contributes beyond that by disclosing what the response contains — comparative CIP metrics, facet/size data, and product prices with checkout links — which matters since there is no output schema. It omits any note on result limits or fallback behavior when a cut is unavailable in a stone.

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 core purpose is front-loaded in the first clause, and the trailing example question is high-value for routing. The middle enumeration of metrics is dense but each item informs the agent about returned content, so nothing is clearly wasted; only the list length borders on heavy.

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 three fully documented parameters, no output schema, and read-only annotations, the description covers nearly everything an agent needs: what is compared, in what context, and roughly what comes back. Only edge-case behavior (unknown cut, stone without that cut) is unaddressed.

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%, so both cut slugs and the gemstone enum are already documented in the schema. The description reinforces that the comparison is scoped 'in one gemstone' and that the gemstone is a single shared context rather than per-cut, but adds no syntax or format detail beyond the schema.

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 verb and resource ('Two cuts side by side in one gemstone') and enumerates exactly what is compared: CIP metrics, tier placement, facets, size, and shoppable products. This clearly distinguishes it from siblings like get_cut_scores or best_cuts_for_gemstone, which surface one cut or a recommendation rather than a head-to-head comparison.

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 example question 'oval or pear for my sapphire?' gives a concrete trigger condition that maps directly to the cut_a/cut_b/gemstone parameters. However, it never names an alternative such as recommend_cut or best_cuts_for_gemstone or says when not to use this tool, so the guidance stops short of full routing.

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