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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful domain framing about who uses the marketplace and why, but says nothing about pagination, result limits, or sort behavior expected of a listing search endpoint.

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 short sentences, front-loaded with the action, followed by domain context and the filter list. Slight redundancy between 'search and filter' and the trailing 'filter by ...' clause, but nothing is wasted.

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 simple, fully-optional, read-only list tool with 100% schema coverage and no output schema, the description supplies enough to call it correctly. The only minor gap is absence of pagination/result-limit hints, which is acceptable here.

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%, including the full category enum and location examples, so the schema already carries the parameter detail. The description merely restates the filter dimensions (category, in-stock, location, query) without adding syntax or semantics beyond it. Baseline 3 applies.

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 pair (search and filter) and resource (supplies/materials marketplace listings), and the domain sentence clarifies what the listings represent. It clearly reads as the list counterpart to marketplace_get_listing and marketplace_list_orders, 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 domain context ('operators buy raw materials here to fulfill capability contracts') implies when this tool is relevant, but there is no explicit when-to-use vs alternatives guidance (e.g. use marketplace_get_listing for a single listing, marketplace_categories to enumerate categories). Usage is inferable rather than stated.

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