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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely new domain behavior — that TZ SELECT selects at most one setup per 4H cycle — but says nothing about the shape or ordering of the returned list, which matters for a discovery tool.

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?

A single sentence with no filler, front-loading the primary list behavior and then qualifying TZ SELECT. Every clause carries information.

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 read-only discovery call, the description is close to sufficient, but with no output schema an agent still doesn't know what each listed entry exposes (identifiers, 4H cycle timing, pricing) or that entries map one-to-one onto the prepare_*_purchase siblings.

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 and the schema is fully closed (additionalProperties: false), so there is nothing for the description to disambiguate. Baseline 4 applies for a parameterless tool.

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 (list) and resource (market setups), and adds a second named item (TZ SELECT). The phrase 'independently purchasable' implicitly links the returned items to the prepare_*_purchase siblings, though the four setups are never named outright.

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 only implied: an agent can infer this is the catalog to consult before calling prepare_4h_setup_purchase or a specific asset's purchase tool, but the description never says so or excludes any alternative. No explicit when-to-use or when-not-to-use is present.

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