price_check

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

Annotations declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered; the description adds genuinely non-derivable behavior — the realized-price range plus confidence plus source-linked comps, and the deliberate exclusion of loose stones and jewelry because under-specified colored stones give unreliable medians. The remaining detail (exact output shape) is carried by the output schema, so it doesn't need restating.

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?

Purpose, input alternatives, and the sibling boundary are all front-loaded in the first two paragraphs, and the exclusion caveat earns its space. The Args block partially duplicates the input schema but adds the missing category enum and example formatting, so the redundancy is mostly justified rather than padding.

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 an output schema present and annotations covering the read-only/open-world profile, the description only needed to explain inputs, routing, and limitations — all of which it does, including the category-coverage caveat. The one real hole is edge-case behavior when both or neither of description and lot_url are provided, on a tool where all three params are optional.

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 0%, so the description must carry the load, and it largely does: it explains the description/lot_url tradeoff, gives a concrete free-text example with brand/model/material, and supplies the category enum values ("handbags", "watches", "cars") plus an inference rule when omitted — none of which appears in the schema. It stops short of saying what happens when both description and lot_url are supplied, or when neither is.

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 ("Estimate a single item's fair-value range from comparable auction sales") and immediately distinguishes itself from the sibling market_stats ("Best for valuing ONE specific piece; for a whole-market read use market_stats"). An agent can route between the two without opening either schema.

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?

Gives explicit input alternatives (free-text description OR auction-house lot URL), an explicit use-case boundary versus market_stats, and an explicit exclusion with a fallback: gemstones and jewelry are held from comp-matching, so use market_stats on `gems` or `jewelry` instead. This is close to a complete routing rule set.

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