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

With no annotations, the description carries full burden. It usefully discloses the 500-character query cap, the live-catalogue scope, and the returned fields, but says nothing about auth/payment requirements, rate limits, or what an empty/missing query does.

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 tight sentences, front-loaded with the operation and scope, then the return shape, then the sibling differentiation. No filler.

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?

No output schema, no annotations, and five undocumented parameters, so the description bears the whole load. It covers purpose, result fields, and the query limit, but leaves the parameter ambiguity and the absence of any auth/cost context unresolved.

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 0% and there are five undocumented string parameters (q, text, query, search, keyword) that appear to be aliases. The description mentions only a query length limit and never clarifies which parameter to supply, whether one or all are needed, or how the aliases differ, so it fails to compensate for the coverage gap.

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 (keyword search over the live x402 service catalogue), names the return fields, and explicitly distinguishes itself from the sibling x402-find by the longer query limit. An agent can identify this tool without opening any schema.

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?

The clause 'Same catalogue search as x402-find, with a longer query limit' clearly implies when to prefer this tool (long queries) and points at the alternative, though it never states an explicit threshold or when-not-to-use rule.

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