iframe_target

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

No annotations are provided, so the description carries the transparency burden. It discloses the core lookup behavior (first match, substring match, returns frameId), but does not state whether the operation is read-only, what happens when no iframe matches, or whether it searches the current page's iframes. These are notable gaps for full transparency.

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 line with an example, front-loaded and free of any filler. Every word contributes to understanding the tool's purpose and usage.

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 one-parameter finder with no output schema, the description covers input meaning and output type. However, it omits no-match behavior and page scope, and the absence of annotations means these details are not supplied elsewhere. The core is present, but edge-case behavior 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?

With 0% schema coverage, the description compensates by explaining that url_substr is the substring matched against the iframe URL, and the example 'iframe_target("player")' clarifies expected usage. It lacks details like case sensitivity or matching scope, but for a single string parameter the meaning is sufficiently clear.

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's function: it returns the frameId of the first iframe whose URL contains the provided substring, with a concrete example. This is a specific verb+resource combo with no ambiguity and no sibling overlap.

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?

The description gives a clear context: use this when you need a frameId for an iframe matching a URL substring, as demonstrated by the example. It does not explicitly mention alternatives or exclusions, but no sibling tool appears to serve the same purpose, so the guidance is adequate.

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