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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds only the currency unit ('Haven Credits') and nothing about return format, volume, or whether listings are filtered – minimal value beyond structured data.

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?

It is a single short sentence with no waste, which is good, but the phrasing is a noun fragment rather than a front-loaded statement of what the tool does, so it reads as under-specified rather than crisp.

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?

With zero params, no output schema, and annotations covering safety, the bar for the description is low – yet it still never states that the tool returns a list of purchasable items or how results relate to buy_item. Adequate but with a clear gap.

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 tool takes zero parameters, so there is nothing for the description to clarify; the baseline of 4 applies. The currency note is a small bonus but parameter semantics are a non-issue here.

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 conveys the resource ('Goods and tools for sale, priced in Haven Credits') but supplies no verb – the action only appears in the title. It also doesn't distinguish this from siblings like market_hours, buy_item, or my_credits, so an agent must infer that this one enumerates listings.

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 indication of when to call this versus market_hours (schedule), buy_item (purchase), or balance/my_credits (funds). No context or exclusions are given, leaving the agent to guess at routing.

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