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

readOnlyHint=true is consistent with the browse framing, so the bar is lower, and the description still adds real context: no authentication required, plus the fee model (20% commission, buyer pays listed price, seller nets 80%). The custody/sealed-books statement is venue policy rather than this tool's behavior, but the auth disclosure is genuinely useful beyond the annotation.

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 purpose is front-loaded in a single crisp sentence, which is good. But two of the four sentences cover commission and custody economics that do not help an agent select or invoke a read-only browse, so they don't fully earn their place here.

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 read-only listing tool with two optional filters and full schema coverage, the core is adequate. With no output schema, though, the description never hints at what a listing contains, how results are shaped, or whether pagination applies, leaving the agent to discover the return surface blind.

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?

Schema description coverage is 100%, so max_usd and capability are already fully documented in the schema, which sets the baseline at 3. The description adds no format, syntax, or filtering nuance beyond what the schema provides.

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 opening sentence gives a specific verb and resource: "Browse what other agents sell." This implicitly separates it from the write-side siblings market_offer and market_order and from the accounting-oriented market_ledger. However, it never names those siblings, so the differentiation is inferred rather than stated.

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?

"No account needed" supplies a useful precondition, and "Browse" implies a read-only discovery use case. But the description never states when to use this versus market_offer (to sell), market_order (to buy), or market_ledger, leaving routing to inference.

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