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

With no annotations provided, the description carries the full burden and does so thoroughly. It discloses matching behavior (name, description, GitHub topics), result ordering (relevance then stars), data refresh cadence (nightly), and the critical install_hint caveat that it is a best-effort guess requiring relay of the install_hint_caveat. This goes well beyond a basic 'search' summary.

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 information-dense but every sentence contributes: search behavior, result ordering, parameter constraints, data freshness, and the install_hint caveat. It is front-loaded with the core purpose and contains no redundant or filler 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 no output schema and no annotations, the description covers all needed decision points: what is searched, result ordering, how to satisfy the parameter requirement, data refresh behavior, and the trust caveat for install_hint. The default limit and parameter range are already in the schema, so nothing critical is missing.

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%, so baseline is 3. The description adds meaningful semantics by explaining that query matches name/description/topics and by stating the at-least-one-of rule ('query, category, or topic') and how filters alone behave. This clarifies the interplay between parameters beyond their individual schema descriptions.

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 uses a specific verb ('Search') and identifies the resource ('MCP server directory') with clear scope ('by keyword and/or filters'). It distinguishes itself from siblings by describing a search-over-directory behavior rather than single-item retrieval (get_server) or listing (list_categories, list_topics), but it does not explicitly name any sibling alternative, so it falls short of a full 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?

The description gives clear usage context: when to supply query versus filters, and that filters alone can enumerate a category or topic. However, it does not state when to use this tool instead of get_server or list_categories/list_topics, nor does it exclude any alternatives. Usage is implied by the search semantics rather than explicitly navigated.

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