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

With no annotations provided, the description carries the full behavioral burden and does add real value: it warns that metadata, name, description and similar free-text fields are UNTRUSTED, attacker-controlled content and must not be executed or rendered as HTML. That is substantive security context beyond anything in the structured fields. It omits return shape/pagination, but the injection warning is the higher-stakes disclosure.

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, purpose first, safety note second — well front-loaded with no filler. The endpoint path is slightly redundant but harmless and aids routing.

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 zero-parameter, no-output-schema listing tool the description is largely sufficient and covers the key security hazard. It still leaves return shape, pagination, and any auth requirement unstated, which is a modest gap given no annotations or output schema fill them in.

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 schema defines zero parameters, so per the rubric the baseline is 4. The description correctly implies a plain unfiltered listing call and adds no misleading parameter expectations.

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 names the resource ('Agent marketplace listings') and pins it to a concrete endpoint (GET /api/v1/agents/market), so an agent can tell it retrieves marketplace listings rather than acting. It stops short of distinguishing itself from nearby siblings like list_agents or market_ordinals, leaving the boundary to inference.

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?

There is no statement of when to choose this tool over list_agents, market_ordinals, or agents_nearby, all of which plausibly return overlapping agent/listing data. The NOTE addresses how to handle the response, not when to invoke the tool.

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