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

Beyond the annotations, the description discloses meaningful behaviors: paginated results, no contact details, USD normalization with conversion at ingest via daily FX rates, and original-currency fields on listings. None of these contradict the readOnlyHint or idempotentHint annotations, and they add useful context about response contents and currency handling.

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?

Three sentences carry distinct, non-redundant information: purpose, return behavior and limitation, and currency semantics. The most important scoping detail (active listings and pagination) is front-loaded, and there is no filler or repetition.

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 compensates by mentioning pagination, absence of contact details, and the USD/currency context, while annotations cover safety and idempotency. Remaining details such as defaults, max limit, and market/category ID sources are already present in the input schema, so nothing critical is missing for an agent to invoke the tool correctly.

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 input schema already documents all 8 parameters, so the baseline is 3. The description adds genuine value by explaining the currency model: all prices are stored and filtered in USD, converted at ingest, with currency_original and price_original reflecting the seller's original pricing. This directly enhances correct use of price_min/price_max and interpretation of returned listings.

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 opens with a specific verb and resource, 'Search active listings on Defici.com global marketplace,' and further scopes the tool by noting pagination, read-only intent, and exclusion of contact details. This clearly distinguishes it from siblings such as get_listing (singular detail lookup) and list_categories (taxonomy listing), even without naming them.

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 provides clear use context: it is a discovery tool for active listings, with pagination and a note that contact details are intentionally absent. However, it does not explicitly name an alternative or state 'use get_listing when contact details are needed,' leaving the contrast to inference rather than direct guidance.

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