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

Annotations already cover safety (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint), so the description appropriately adds context beyond them: the upstream provider (Jina), the return format (markdown), and that authentication is now mandatory. It does not mention result counts, rate limits, or pagination, which is the remaining gap.

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 tight sentences with the core purpose front-loaded and the prerequisite immediately after, with no filler. The API-key sentence partially duplicates the _apiKey schema description, which is a minor 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 two-parameter read-only search tool, the description plus rich schema and annotations cover everything needed to invoke it correctly: what it returns, which provider backs it, and the auth prerequisite. No output schema exists, but the description states the output format, which is sufficient.

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 both parameters (query and _apiKey) are already fully documented in the schema, including the key URL. The description restates the API-key requirement without adding syntax, format, or constraints beyond what the schema provides, so 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 ('Web search returning the top results as markdown, via Jina'), so an agent knows exactly what the tool does. It does not name or distinguish itself from near-neighbors like read_url, search_within, or deep_research, which keeps it 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 only implied by the phrase 'Web search' — there is no explicit when-to-use guidance and no mention of when to prefer read_url, search_within, or deep_research instead. The API-key prerequisite is stated, which is useful context, but it is a requirement rather than routing guidance.

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