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

Beyond the readOnly/idempotent annotations, the description discloses non-obvious behavior: the search is scoped to a subset of a 300+ tool server, matches are returned with full input schemas, and an empty query degrades to a full name listing. It does not mention ranking behavior, result ordering, or any rate limits, but for a read-only lookup the important behavioral traits are surfaced.

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 sentences, front-loaded with the purpose, then scope, then the call pattern – no filler. The parenthetical list of the 300+ hidden tool categories is somewhat long but earns its place by telling the agent how much is behind this gateway.

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 an output schema present, the description needn't describe return values, and it still covers what an agent must know: what the search covers, how to phrase the query, what comes back (full input schemas), and how to act on results via call_tool. 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?

Schema coverage is 100%, so both fields are already documented, making 3 the baseline. The description adds real semantic value for `query` by framing it as 'a few words for the job' and by explaining the no-query case, which is a behavioral branch the schema does not convey. `limit` is left entirely to the schema, which is acceptable given its self-explanatory description.

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 ('Find the ... tool for a task', 'get back the best matching tools with their full input schemas') and distinguishes itself from the sibling call_tool, which it explicitly names as the follow-up step. The scope note ('lists only the tools that reach a price; the server has over 300 more') makes the search domain concrete, though the phrase 'Last Price tool' is product jargon that takes a beat to parse.

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 gives clear sequencing: pass a short query to get matches, then invoke one via call_tool or by name, and with no query it returns every tool name. That covers the main use pattern and names the alternative tool. It stops short of saying when *not* to use it (e.g., when the tool name is already known), which keeps it from a 5.

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