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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds real value beyond that: it lists exactly which fields come back (id, title, url) and that this returns document summaries, not full text. It omits any mention of result limits, ranking, or pagination behavior, which keeps it from 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 sentences, zero filler. The content scope is front-loaded and the follow-up action (fetch by id) closes the sentence, so the agent gets purpose and next step in one pass.

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 one-parameter read tool with no output schema, the description supplies the two things structured fields can't: the corpus being searched and the shape of the results. Nothing needed to invoke it correctly is missing.

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?

There is a single parameter at 100% schema coverage, and the schema already gives a worked example ("cloud cost reduction", "RAG") plus length bounds. The description only restates "by keyword," adding essentially nothing about query matching, so the baseline 3 holds.

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?

Specific verb (searches) plus a precisely enumerated resource scope: services, case studies, FAQ, work experience and articles on a named site. It also states the return shape (id, title, url), which no sibling tool offers, so an agent can distinguish it from `fetch` and `list_services` without opening a schema.

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 explicitly routes the second step: "pass an id to fetch for the full text," which tells the agent this is the discovery step and `fetch` is the retrieval step. It stops short of stating when NOT to use search (e.g., when a known id or URL is already in hand), so it falls just short of the top mark.

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