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

Annotations only cover the safety profile (readOnlyHint=true), so the description carries the rest and does add value: it discloses the exact shape of each returned row, including that price is per-month and free is a 1/0 flag. It does not mention pagination, ordering, or result-count behavior even though limit/offset exist, which keeps it out of 5 territory.

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 short fragments, front-loaded with the resource, then the return columns, then the routing hint. Every token earns its place with no filler or repetition.

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 compensates by listing returned columns and pointing to fetch for detail. However, for a 4-parameter search tool it leaves limit/offset/verbose entirely unexplained, so an agent cannot know how to page or what verbose changes.

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 coverage is only 25% (only 'query' is described, with an example). The description says nothing about limit, offset, or verbose, so three of four parameters are undocumented in both the schema and the description. It adds no meaning beyond the schema for any parameter.

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 and resource: 'Find vibe coding / AI tools', and the column list ('id|name|category|$from/mo|free(1/0)') makes the result set concrete. It partially differentiates from siblings like recommend_tools by routing detail lookups to fetch(id), though it does not distinguish itself from list_alternatives or compare_tools.

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?

Explicitly names the follow-up alternative and the condition that selects it: 'Use fetch(id) for details.' That is real routing guidance. It stops short of a 5 because there are no exclusions or conditions telling the agent when NOT to use search (e.g. vs. recommend_tools or list_alternatives).

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