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

Goes well beyond the readOnlyHint annotation: it discloses that Agentropolis makes no request to Coinbase, does not cache or republish Bazaar data, and that the tool only returns a link the user must open themselves. These are material behavioral facts an agent could not infer from the schema or annotations.

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?

Front-loaded with the purpose and then the when-to-use condition, with no wasted preamble. 'Read-only' is mildly redundant with readOnlyHint=true, and the parentheticals add length, but each sentence carries useful 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?

An output schema exists, so return values need no elaboration, and the description still notes the return is a link. For a single-parameter, side-effect-free tool, nothing needed for correct invocation is missing.

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 coverage is 100% so the baseline is 3, but the description adds a concrete invocation example ({'q':'web search'}) that shows the argument shape in practice. It does not restate the maxLength or omit-for-home-page rule, which the schema already covers.

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 and resource ('Build a URL that searches Coinbase's x402 Bazaar'), and clarifies it produces a link rather than performing a search. It also implicitly differentiates from siblings like search_kits by naming the Agentropolis index as the contrasting source.

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?

Explicitly says when to use it ('when you want x402 services that may be missing from the Agentropolis index') and what the result is for ('for you or your user to open'). It lacks an explicit when-not or a named alternative sibling, but the condition is clear enough to route correctly.

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