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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false, so safety is covered, and 'Read-only' merely repeats that. However, the description adds genuinely new behavioral context: only ACTIVE listings are returned, which the annotations do not convey. It omits result-cap/pagination behavior despite a limit param with no offset.

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?

Two sentences, zero filler, with the core browse/search scope front-loaded ahead of the capability list. Every clause carries information the agent can use.

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 an all-optional, single-object list tool it covers scope, filtering dimensions, sorting, and the active-only constraint. The only gap is that with no output schema it does not describe the shape of returned listings or pagination/cap behavior, which an agent would benefit from knowing.

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 the schema already documents all six parameters with enums and bounds. The description restates search scope, category values, price unit (cents), and sort options but adds no format, syntax, or default detail beyond the schema — 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+resource ('Browse and search ... marketplace listings') and frames itself as the agent equivalent of the /marketplace UI. It is clearly distinguishable from create_listing, upload_digital_good, and my_purchases among the siblings.

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?

Usage is implied by the description (browse/search listings), and it notes the read-only nature, but it names no alternative tools or when-not-to-use conditions (e.g., use my_purchases for owned items). The agent must infer the selection context from the name alone.

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