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

Annotations cover safety (readOnlyHint) and open-world scope, so the bar is lower; the description still adds substantive traits: the data source (sitemap), the exhaustive ~3.4k-5k enumeration including uncategorized items, and the mutation-timestamp semantics of changed_since. It does not cover pagination limits or ordering, but the added provenance detail is valuable.

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?

Four dense sentences, each carrying a distinct payload (contents, provenance, usage tip, ID caveat) and front-loaded with what the tool returns. Slightly information-heavy, but nothing reads as filler.

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?

An output schema exists, so return-field documentation is unnecessary. With market scoping, catalogue breadth, filter semantics, and the ID-vs-sku caveat all covered, an agent has everything needed to call this correctly against its sitemap-oriented siblings.

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 coverage is 100%, so baseline is 3. The description goes further by explaining the semantics of changed_since ('only new or updated products' / new-arrivals feed) and by clarifying the identity of the id field used for product references, adding meaning the schema itself doesn't convey.

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 precise verb and resource ('a page of Hermes' full catalogue index for one market') and enumerates the fields returned (product URL, slug, URL identifier, last-modified date). It distinguishes itself from siblings by noting it includes items 'no category listing surfaces' and by warning that product_id differs from the sku of hermes_category/hermes_search.

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 context: use changed_since to turn the tool into a new-arrivals feed, and implies broad enumeration vs the narrower category/search siblings. It stops short of an explicit 'use X instead when Y' routing statement, so the differentiation is contextual rather than directive.

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