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

Annotations already declare readOnlyHint and idempotentHint, but the description adds real value beyond them: health_status is *stored*, not live; the tool does not ping or proxy; sponsored/Featured rows are sorted first and marked; plus auth modes (X-API-Key, Bearer, x402 settle after 402). These are behavioral facts no annotation conveys.

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 core is well front-loaded (purpose, returns, alternatives, read-only caveat). But the trailing auth/signup/x402 block and especially the meteora_brief dynamic-pricing sentence are irrelevant to searching listings and bloat the definition with boilerplate that does not help select or invoke this tool.

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 3-parameter read-only search with no output schema, the description covers return contents, result cap, sorting/sponsorship, freshness caveat, and auth/payment paths. An agent has everything needed to call it and interpret the response correctly.

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% and all three parameters are self-documented, so the baseline of 3 applies. The description repeats the 10-row cap and sponsored-first ordering that the schema's own limit field already states, and adds nothing about keyword matching or category slug semantics.

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 ('Search the curated MCP registry') and enumerates the return fields (name, short description, mcp_url, health_status) plus the 10-row cap, so the agent knows exactly what comes back. It differentiates itself from check_health and rank_tools_for_task, but never distinguishes itself from the sibling search_products, which is the most likely confusion.

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?

Explicit routing: use check_health when last_checked_at is needed, connect to mcp_url yourself, and call rank_tools_for_task before paying a listing. Each alternative is named with the condition that selects it, which is exactly what usage guidance should do.

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