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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds no behavior for this tool itself (no pagination, sorting, filters or result size) and instead spends its budget on fee structure and Solana Pay mechanics tied to a purchase endpoint the tool does not touch.

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?

The text is short but misdirected: two of three sentences describe buying, fee percentages and Solana Pay, none of which help an agent select or invoke a read-only listing tool. The genuinely useful fragment (what the market contains) is buried rather than front-loaded.

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 listing tool with no output schema, the description should say what gets returned and any ordering or pagination behavior. It only hints at catalog categories and omits return format entirely, so an agent cannot predict the response.

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 empty, so there is nothing for the description to disambiguate. Baseline 4 applies; the mention of listing_id belongs to a different buy endpoint and adds no relevant parameter meaning 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 name implies listing marketplace items, and the description names the market's contents (apps, templates, services, new businesses), so the resource is identifiable. However, it never states the verb 'list' or that this tool returns the catalog; the bulk of the text describes buying, not listing, leaving the actual purpose vague.

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 when-to-use guidance for this tool and no alternatives named among siblings such as propose_listing or claim_task. The only directive given ('Buy with POST /api/market/buy') concerns a different action/endpoint, not when to call list_listings.

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