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

Annotations already cover the safety profile (readOnly, non-destructive), but the description adds genuinely new behavioral context: it never triggers payment, trust scores derive only from verified non-wash payments, and affiliate first-party kits arrive in a separate labeled block. That disclosure of result provenance goes beyond 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?

Three tight sentences with the scope front-loaded and zero filler; every clause (scope, safety, trust provenance, affiliate labeling) carries distinct information.

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 an 8-parameter discovery tool with no output schema, the description covers what it searches and how trust/affiliate results are handled, but says nothing about filter semantics, ordering, result count, or pagination. Adequate but with clear gaps given the parameter richness.

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 only 13% — only 'q' is documented, leaving kind, rail, category, min_trust, paid_only, max_price_usd and limit unexplained in both schema and description. Passing mentions of 'trust scores' and paid APIs gesture at min_trust/paid_only but give no semantics, so the description fails to compensate for the coverage 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?

Specific verb ('Search') plus a concrete resource, and it enumerates exactly what the index contains (MCP servers, x402/MPP paid HTTP APIs, A2A agents, kits). It does not explicitly contrast itself with siblings like get_kit or list_categories, so it stops short of a 5.

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 (this is the entry-point discovery tool) and 'Read-only; never pays' frames the context, but there is no explicit when-to-use-vs-alternative guidance and no prerequisites stated. The agent must infer that get_kit/get_kit_manifest are the follow-ups.

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