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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds the deprecation/backward-compatibility status and warns that the return shape differs from `search`, which is useful context, but it never explains how the shape differs or what is returned.

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 compact sentences that front-load the site identification and the legacy status, then the sibling routing. Efficient, with only mild redundancy between the title's 'previous name' and the body's 'previously named feature.'

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 simple read-only 2-parameter search with no output schema, the purpose and routing are adequately covered. However, since it explicitly claims the return shape differs from `search` and there is no output schema, the description leaves a real informational gap about what callers actually get back.

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?

At 50% schema description coverage, the description must compensate for undocumented parameters, and it offers nothing about `limit` (range 1-20, default 5) or any query syntax beyond what the schema already contains. The description adds no parameter meaning over the schema.

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 identifies a concrete verb+resource (site search) and explicitly frames this as the legacy/renamed version of the search feature retained for backward compatibility. It clearly differentiates itself from the sibling `search` by noting the same behavior with a different return shape, though the 'previous name' framing makes the identity slightly indirect.

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?

It states an explicit when-not-to-use and names the alternative: 'When using it newly, please use search' and 'kept for those already connected.' An agent knows exactly to prefer `search` for new work and to only fall back to this tool for existing integrations.

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