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

With no annotations, the description carries the burden. It discloses what the tool returns (matching servers with slugs, tool counts, pricing) and its proactive nature. It does not mention rate limits or auth, but for a read-only search tool, this is sufficient and adds value beyond the schema.

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 well-structured and efficient: purpose first, then usage triggers, return info, and a pointer to the next step. The list of use cases is long but purposeful, not fluff. Every sentence earns its place.

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?

Given the tool's simplicity (3 params, no output schema), the description covers purpose, when to use, return content, and relationship to xpay_details. It is complete enough for an agent to invoke correctly, though it could have briefly explained what 'servers' are in this context.

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 baseline is 3. The description adds value by providing natural language query examples (e.g., 'research a company', 'find contact emails') and clarifying the return structure, which helps understand the query and limit parameters. Not a full substitute, but a clear enhancement.

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 clearly states the tool searches XPay Hub for paid API services, with a specific verb and resource. It distinguishes itself from siblings by listing concrete use cases and pointing to xpay_details as the next step for viewing a server's full tool list.

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?

Provides explicit proactive usage guidance with a comprehensive list of scenarios (search web, find emails, enrich contacts, etc.). It also tells the user to follow up with xpay_details, marking a clear workflow. No alternatives are named, but the context is unambiguous.

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