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

With no annotations, the description carries the full behavioral burden and adds important context beyond the schema: it explains that services are verified via manifest payee matching, that names and descriptions are untrusted data and never instructions, and that this server cannot pay them. It does not explicitly state read-only behavior or pagination/rate-limit characteristics, but it provides unusually strong trust and safety semantics 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?

The description is front-loaded with the core purpose and then efficiently adds scope, verification, trust, and payment warnings. Every sentence contributes useful information, and there is no redundant or filler text.

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-oriented directory search with an output schema, the description is nearly complete: it covers purpose, optional filters, trust model, and a key safety warning. It could be slightly more complete by explicitly noting read-only behavior or how results are ordered, but the schema and output schema cover those details adequately.

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%, and the schema already explains query matching, orderBy values including defaults, and maxPrice unit syntax. The description only restates that query and maximum price are optional filters and does not add syntax or meaning beyond what the schema provides, so the baseline of 3 is appropriate.

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 description states a specific verb and resource: 'Find paid services (APIs that charge per request) listed in the on-chain service directory.' It also clarifies scope with 'This is the directory; there is no separate list,' which distinguishes it from any sibling or implied listing tool. Sibling tools are unrelated account/miner/transaction utilities, so no further differentiation is needed.

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 description clearly implies when to use the tool: to find paid services, optionally filtered by query and maximum price. The note that 'This is the directory; there is no separate list' helps an agent understand it is the canonical discovery endpoint. It does not give explicit when-not conditions or alternatives, but no relevant alternatives exist among the siblings.

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