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

Annotations already mark this as read-only and open-world, and the description adds meaningful context: free-call limits, paid in-band x402/card behavior, and the two data sources. That is useful operational detail beyond the annotations, though it does not discuss output behavior or rate-limit handling beyond the free-call count.

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 compact and mostly front-loads the key constraints: pricing, payment mechanism, search scope, and filters. The purpose appears after the pricing sentence, which is slightly less ideal, but there is little wasted 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 search tool with an output schema and read-only annotations, the description covers scope, sources, filters, and payment mechanics sufficiently to call it correctly. Remaining gaps are mainly sibling differentiation and fuller parameter semantics.

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 0%, so the description must carry parameter meaning. It names q, explains type as mcp|x402, and states limit<=100, but it does not describe query syntax, pagination behavior, or why schema lists limit as a string.

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 search action over '~13,000 agent tools,' split into MCP servers and x402 APIs, so the resource and scope are clear. It does not explicitly differentiate itself from close siblings such as dump_agent_tools, mcp_servers, or x402_services.

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?

It implies usage as a unified search across both MCP and x402 entries, and names the available filters. However, it gives no explicit when-to-use guidance versus sibling tools like apis_search, mcp_servers, or dump_agent_tools.

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