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

Annotations already declare readOnly, idempotent, and open-world hints, and the description adds substantial behavioral context beyond those: backend clamping of `limit`, the meaning of `verifiedBrand=false`, the absence of a country filter, the global scope of every card, and the representation of the cheapest purchasable variant. No contradiction exists.

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 description is dense but every sentence earns its place: primary behavior, required inputs, optional filters, global-scope caveat, return shape, and ranking guidance. It is front-loaded with the core discovery behavior and then efficiently covers each important semantic nuance.

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?

For a 9-parameter tool with no output schema and no parameter descriptions, the definition is exceptionally complete: it covers required input combinations, filter semantics, return fields, cardinality, global behavior, and sizing limits. An agent has everything needed to invoke this tool correctly and interpret its results.

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 carries full responsibility for parameter meaning, and it delivers. It explains `query`, `brandSlug`, `currency`, `minPrice`, `maxPrice`, `verifiedBrand`, `inStockOnly`, `source` with enum values, and `limit` — including the critical clamp behavior that contradicts the schema's maximum of 50.

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 states a specific verb ('Discover') and a specific resource: droplinked inventory, with one card per product and a defined set of catalog sources. It clearly distinguishes the tool's scope from siblings like search_products or list_shop_products by emphasizing cross-source inventory discovery rather than general product search or per-shop listing.

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 gives clear invocation guidance: at least one of `query` or `brandSlug` is required, optional filters are enumerated, and notable limitations are stated (no country filter, `verifiedBrand=false` is not 'unverified only', `limit` clamps at 25). It stops short of explicitly naming sibling alternatives or stating when to prefer another tool such as search_products or find_merchant.

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