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

Annotations already declare readOnly, idempotent, non-destructive, open-world, so the safety profile is covered. The description adds the -1 sentinel semantics, which is useful, but discloses nothing else about behavior such as lookup scope or latency; an output schema covers return values.

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 sentences, no filler: the first front-loads what is returned and the scope, the second handles the one non-obvious parameter convention. Every sentence earns its place.

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 annotations supplying safety traits and an output schema supplying return values, the description only needs to cover purpose and the estimate sentinel, which it does. The one gap is choosing this tool over price_item or where_to_buy_or_sell.

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 all six parameters are already documented, including the -1 convention for estimate_low/estimate_high. The description restates that convention rather than adding syntax or meaning beyond the schema, so the baseline 3 applies.

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 resource — new, used, and resale prices — scoped to 'one named item', which is enough for an agent to know it is a comparison lookup. It does not name price_item or where_to_buy_or_sell to differentiate itself, so sibling routing is only implicit via the estimate parameters.

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 second sentence implies a workflow: pass an already-priced range, or -1 when the title still needs pricing, which hints that price_item runs first. However, there is no explicit when-to-use-this vs. either sibling and no exclusion guidance.

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