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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed-world scope, so the safety profile is covered structurally. The description adds only the corpus scope (indexed sources, security-first scoring), with no note on ranking, result limits, or refresh/coverage caveats.

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?

A single front-loaded sentence that names the action and the resource immediately, with the parenthetical detail earning its place by conveying corpus breadth and trust signal. No filler or redundancy.

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 simple two-parameter read-only search with no output schema, the description is minimally adequate but silent on what a result contains and how results are ordered, which matters for an agent deciding whether to rely on it. It stops at the purpose statement.

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 both parameters are documented in the schema, so the baseline is 3. The description adds nothing about query syntax, how 'category' values are determined, or the fact that neither parameter is required.

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 gives a specific verb ('Search') and a clearly bounded resource ('MarketNow registry of indexed MCP servers'), plus useful scale context (68k+, GitHub/npm/PyPI, security-scored). It does not explicitly distinguish itself from siblings, though most siblings (check_domain, fingerprint_tool, translate_credential) are obviously different operations.

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?

There is no when-to-use or when-not-to-use guidance, no mention of alternatives, and no statement of prerequisites or intended context. An agent must infer that this is the discovery entry point of the registry rather than being told.

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