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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered; the description adds meaningful context beyond that: results are derived from text vectors, embedding is a prerequisite, and each nearest-page result carries the two closest passages returned under a "quoted" key. It does not say what happens when the site has not been embedded.

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?

Four tight sentences with the core purpose front-loaded and no filler. The phrasing is choppy ("Passages come under 'quoted'." is a bare fragment) but every sentence carries information.

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 does the work of explaining the return shape (grouped pages, or nearest pages each with two quoted passages) plus the embedding prerequisite. Remaining gaps are limit scoping and failure behavior for un-embedded sites, which are minor for a read-only lookup tool.

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 100%, so the schema already documents site, path, and limit; the description only reinforces path's two behaviors. It adds no meaning for limit (whether it caps groups or individual pages) and gives no format hints beyond the schema's example domain.

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?

Names a specific resource (pages that mean nearly the same thing, grouped, potentially competing for one search) and distinguishes the two modes of operation (site-wide grouping vs. nearest-to-a-path). It never names a sibling such as mttr_near or mttr_gaps, so an agent must infer the boundary from the wording alone.

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?

Gives a real precondition — "the site must have been embedded" — and explains that supplying a path switches to nearest-page mode while omitting it yields grouped results. There is no explicit guidance on when to pick this over alternatives, but the usage context is clear.

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