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

The annotations already declare readOnlyHint, idempotentHint, and non-destructive, so the safety profile is covered; the description adds real value on top by disclosing relevance-based ranking and the return shape ("compact tool cards with canonical URLs"). It does not say what happens with zero matches or whether results are ever truncated, which keeps it below a 5.

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?

Two dense sentences: search scope first, filter options second, return shape and next-step routing last. Nothing is duplicated and no sentence could be removed without losing information the agent needs.

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 seven-parameter search tool with no output schema, the description supplies the indexed fields, ranking behavior, filter dimensions, and return-card shape, which is nearly everything needed to call it correctly. The remaining gap is edge-case behavior (empty result sets, result caps beyond the schema's limit) which the agent must infer from the schema.

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 every parameter (including the pricing synonym rules and the list_* cross-references) is already documented in the schema. The description only restates the filter categories at a high level, adding no syntax, constraint, or interaction detail beyond the structured fields, so the baseline 3 applies.

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 states a specific verb and resource ("free-text search over the AI tools directory") and enumerates the indexed fields (names, aliases, subtitles, descriptions) plus the optional filter dimensions, so the agent knows exactly what kind of operation this is. It separates itself from get_tool but never contrasts with the sibling list_tools, which is the closest ambiguous alternative for an agent with no query in mind.

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?

Clear routing context is given: use this for free-text lookup, then "call get_tool for details" once a candidate is found, and the optional filters are framed as refinements. There are no explicit exclusions (e.g., when to prefer list_tools or list_categories instead), so it stops short of full when/when-not guidance.

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