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

With readOnlyHint, idempotentHint, and destructiveHint already covering safety in the annotations, the description adds useful behavioral context beyond them. It discloses that the tool refuses rather than returning a near match, explains that a refusal includes a reason, and clarifies that a fund refusal means ETFIQ does not publish it. It still does not describe result shape, pagination, or optional parameter behavior.

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?

The description is three tight sentences with the core purpose front-loaded. Each sentence adds useful information: lookup scope, usage sequencing, and refusal semantics. No wasted wording.

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 search tool with no output schema and zero schema description coverage, the description covers purpose, usage sequencing, and an important refusal behavior. However, it omits what the optional desk and limit parameters do and gives only minimal indication of the return shape beyond mentioning a ticker. These gaps matter for correct invocation.

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 0%, so the description carries the burden of documenting three parameters. It explains the required query parameter as accepting a ticker, fund name, or word from the name, which is useful, but it says nothing about the desk or limit parameters. With two of three parameters completely opaque, the compensation is insufficient.

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 gives a specific verb and resource: find US listed ETFs by ticker, fund name, or a word from the name. It also distinguishes this tool from etf_profile by framing itself as the first step for loose fund names. An agent can tell what this tool does without opening the 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 says to use this FIRST when the user names a fund loosely, then call etf_profile with the returned ticker. That provides clear sequencing and one named alternative. It does not state when not to use it, such as when the exact ticker is already known, or mention other search-like siblings such as etf_screen.

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