session_download

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

With no annotations, the description carries the behavioral burden. It transparently states the side effect location (~/.cache/camoufox-research/downloads/), the return value (path), and that selector mode "catches" a download. It does not cover failure behavior or timeout usage, but the core actions and persistence effect are disclosed.

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 extremely compact and front-loaded, with each sentence adding necessary information: the action, parameter meanings, save location, and return value. No filler is present, and the most important usage distinction is placed immediately.

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?

Given that an output schema exists and the tool has only three simple parameters, the description is mostly complete. It covers the purpose, parameter semantics for url and selector, the save directory, and the return value. The only notable gap is the timeout parameter and possibly the relationship between url and selector (alternative vs. combined usage).

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?

The schema has 0% description coverage, so the description must compensate. It explains two of three parameters well: url is a direct link, selector triggers and catches a download. However, timeout is left entirely unexplained even though it has no schema description; its purpose is only inferable from its name and default of 30.

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 starts with a clear verb and resource: "Скачать файл" (download a file). It clarifies two modes — direct link via url, or clicking a download button via selector — which makes the tool's function distinct from sibling navigation/reading tools. It does not explicitly contrast with any sibling, but the core purpose is unambiguous.

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 clear context for use: pass a direct link in url, or use selector to trigger and catch a download. This effectively tells an agent when to use each parameter. It does not mention when not to use the tool or name alternatives, so it does not reach the top score.

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