Scrape any URL (Web Unlocker)

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

With no annotations, the description carries the full burden. It transparently discloses the key behavioral trait that it always spends Bright Data credit (a cost implication) and implies it can bypass blocks. It doesn't cover every edge case like error handling or rate limits, but the most critical behavioral disclosure is present and accurate.

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 concise sentences with no fluff. It opens with the most important warning (cost), then provides the alternative, then lists specific use cases. Every sentence earns its place and the structure is front-loaded.

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 tool with 8 parameters and no output schema, the description provides strong decision-making context: cost implications and when to use vs. alternatives. It doesn't explicitly describe the return format beyond the data_format enum, but the schema covers that. Given the absence of annotations, it is reasonably complete.

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 input schema covers all 8 parameters with descriptions (100% coverage), so the baseline is 3. The description adds marginal value by mentioning screenshot output as a reason to use the tool, which maps to the data_format parameter, but it does not add meaning to the other parameters beyond what the schema already provides.

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 what the tool does: it scrapes any URL using Bright Data's Web Unlocker, as indicated by the title and the statement that it always spends Bright Data credit. It also distinguishes itself from the sibling smart_scrape by positioning itself as the paid fallback for blocked sites, making the resource and scope explicit.

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 provides explicit when-to-use guidance: prefer smart_scrape for read-only fetches, and use unlocker_scrape directly only for screenshots, unconditional Bright Data forcing, or when smart_scrape confirms a hard block. It also names the alternative tool, making the decision process clear.

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