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

Goes well beyond the readOnlyHint/openWorldHint annotations: it discloses the price ($0.02 USDC via x402), that invoking it returns an HTTP request plus x402 payment requirements rather than data, and that payment via any x402 client is required to actually get results. This is the kind of paid/two-phase behavior an agent cannot infer from structured fields.

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?

Dense and front-loaded with the price and action, with no wasted prose. It loses a point only for restating enum values (cloud/local, python/typescript...) that the schema already declares.

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?

With no output schema, the description usefully explains both the payload (repo URL and description) and the payment round-trip. Only the undocumented limit parameter and the absence of a free-vs-paid sibling comparison leave minor gaps.

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 the load, and it does for five of six parameters (q, category, language with example values, scope, official). The limit parameter is never explained, which is the only substantive 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 (Search) and resource (MCP servers) plus the exact filter dimensions, and implicitly distinguishes itself from siblings like mcp_servers_sample and dump_mcp_servers by naming the full searchable corpus size (4,259). An agent can tell what this does without opening the 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?

Usage is implied by the description of filters and the payment flow, but there is no explicit when-to-use guidance and no routing to the obvious alternatives (mcp_servers_sample, dump_mcp_servers) that a sibling-aware agent would want to weigh against paying $0.02.

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