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

No annotations are supplied, so the description carries the whole burden, and it does disclose substantive behavior: every item carries a price in the actual payment currency, a USD estimate, real stock, and 'exact non-custodial steps to buy it.' That non-custodial framing is genuinely useful and not inferable from the schema. It omits pagination, result limits, and an explicit read-only/no-side-effects statement, keeping it below a 5.

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 purpose and scope are front-loaded in the first two sentences, followed by the filter list and the routing call-to-action. The long enumeration of six item types is informative rather than filler, though the all-caps opener is more marketing than specification.

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 no output schema, the description must convey what comes back, and it does: price in the payable currency, USD estimate, stock level, and purchase steps. Filters and the aggregation scope are covered, leaving only pagination/ordering behavior unspecified for a six-parameter read tool.

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 filters are already documented in the input schema with enums listed inline. The description only restates the filter names (q, type, market, availability, currency, max_price) without adding semantics such as how max_price interacts with the 'in that item's own currency' caveat. Baseline 3 applies when the schema does the heavy lifting.

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 names the resource (an aggregated catalog) and enumerates exactly what it spans: fixed-price NFTs, NFT pools, APEX commodity pools, land deeds, buildings and sponsorships. That scope statement lets an agent distinguish it from narrower siblings such as catalog_product or commodity_markets, though it never names those siblings explicitly.

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 FRONT DOOR FOR BUYING' plus 'Start here instead of querying six separate systems' gives a clear routing instruction for when to pick this tool over per-system queries. It does not state when to prefer a sibling (e.g. a single-product lookup) or what to do when the catalog returns nothing, so it stops short of full when/when-not coverage.

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