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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds one genuinely new behavioral fact — the call is free — but says nothing about result volume, ordering, or whether the listing is scoped to the caller's current port versus all ports, which matters for a discovery call.

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 short sentences with no filler, and the resource is front-loaded before the cost note. The telegraphic, verbless style is terse enough that it reads more like a catalog entry than an instruction, costing it a point.

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 parameters and no output schema, the description carries most of the burden, and it does identify the returned entities and the cost. It stops short of explaining result size, pagination, or the relationship to stall_detail, which an agent needs to choose correctly between two closely related discovery tools.

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; baseline 4 applies. Nothing in the description misleads about inputs.

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 ('stalls in this port's bazaar and the goods they sell'), which is concrete, but it is a noun phrase with no verb and never contrasts with the sibling stall_detail. An agent can guess this is the list-level counterpart to the detail tool, but the definition itself does not establish that distinction.

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?

'Price: free' gives an implicit cost-based reason to prefer this tool, which is a small piece of guidance. There is no explicit statement of when to call this versus stall_detail, nor any prerequisite or exclusion, so the when-to-use decision is left almost entirely to inference from tool names.

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