get_similar_etfs

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

No annotations are provided, so the description carries the full burden. It discloses the data source (Yahoo Finance's recommendation engine) but doesn't explicitly state it's a read-only operation or describe output format or potential limitations. The implication of 'find' suggests read-only, but that's not stated outright.

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 a single, concise sentence that front-loads the primary action ('Find ETFs similar') and adds a brief purpose ('Useful for discovering alternatives'). No unnecessary words or details.

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 tool with one parameter and no output schema, the description covers the core function and context. It doesn't specify the return format (e.g., list of tickers) or any pagination, but these are minor gaps for such a straightforward lookup. The absence of annotations is partially compensated by the clarity of purpose.

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 100%, and the parameter 'symbol' is well-documented in the schema with an example. The tool description doesn't add parameter-specific details beyond what the schema already provides, so the baseline of 3 applies.

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 clearly states the tool finds ETFs similar to a given ticker, using the verb 'find' and the resource 'similar ETFs'. This is distinct from siblings like get_etf_quote or get_etf_summary, which focus on other aspects.

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 provides clear context by saying it's 'useful for discovering alternatives', which implies when to use it. However, it doesn't explicitly contrast with sibling tools like compare_etfs or mention when not to use it, so it lacks exclusions.

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