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

The annotations (readOnlyHint=true, openWorldHint=true) already cover safety and the external nature of the input. The description adds the specific scope of detection (frameworks, CMS, analytics) but does not disclose any additional behavioral traits such as potential rate limits, network requirements, or likely output format. It adds some value but not rich behavioral context.

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 two concise sentences, front-loaded with the primary purpose and followed by a practical use case. Every sentence contributes value, and there is no redundant or verbose language.

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, no output schema, and safety annotations, the description adequately covers purpose and usage. It does not explicitly describe the return format or limitations, but the intended behavior is clear enough for a competent agent. The description is complete for the tool's complexity, though slightly more detail on output would push it to a 5.

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 has 100% description coverage, with the 'url' parameter fully described as 'The full URL to analyze (must start with http:// or https://).' The tool description adds no extra meaning beyond what the schema 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's function: 'Detect technologies used by a website (frameworks, CMS, analytics).' This uses a specific verb and resource, and the examples (frameworks, CMS, analytics) distinguish it from sibling lookup tools like lookup_headers or lookup_dns, which focus on other aspects of a website.

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 a clear use case: 'Use when analyzing a competitor's tech stack.' This gives context for when to employ the tool but does not explicitly mention alternatives or when not to use it, so it stops short of a 5.

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