Detect changes on a page since last fetch

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It openly describes that the tool fetches the URL, caches versions, returns both versions, and that the first call stores a baseline. This goes beyond a simple verb phrase and gives insight into side effects (caching) and statefulness. It does not mention rate limits or authentication, but for a diff tool this is adequate.

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 sentences with efficient, front-loaded content: the action, the return values, and the caching behavior. Every sentence earns its place, with no fluff or repetition. It is well-structured and easy to parse.

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?

Despite a clear core explanation, the tool has 4 parameters with zero documentation in both schema and description, and no output schema or annotations. The description covers the high-level logic but omits parameter-specific guidance, which is essential for correct invocation. An agent would be left guessing what 'free_only' or 'force_bright_data' mean. This makes the description incomplete for a tool of this complexity.

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, and the description does not explain any of the four parameters (url, free_only, data_format, force_bright_data). Only 'url' is implied by 'Fetch a URL,' but the other parameters' purposes and effects remain completely undocumented. The description adds no semantic value beyond the schema types.

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: 'Fetch a URL and compare it to the previously cached version.' This distinguishes it from sibling tools like smart_scrape or smart_crawl by emphasizing the change-detection aspect. It also specifies the return values, making the purpose 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 explains the caching behavior ('First call always stores a baseline; subsequent calls detect changes'), which implies when to use the tool (for tracking page changes over time). However, it does not explicitly contrast it with alternatives or state when not to use it, leaving usage guidance implicit rather than direct.

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