Look up several websites at once

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

With no annotations provided, the description bears the full burden of behavioral disclosure. It adds important context by stating that full detail is returned for each URL and that the tool 'counts one scan per URL against the caller's plan,' which is a meaningful quota/billing behavior. It doesn't cover error handling or auth, but those are less critical for this read-style operation.

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?

Four sentences, all functional: capability, use case, alternative, and quota impact. Key information is front-loaded, with zero filler or repetition.

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 one well-documented parameter and no output schema, the description covers purpose, usage, routing, and plan impact. Nothing essential for selecting or invoking the tool correctly 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?

The input schema already documents the single parameter well, including min/max items and that bare domains are fine, so schema coverage is 100%. The description reinforces the batch aspect and return detail but adds no new parameter-level semantics beyond the schema.

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 states a specific verb and resource: 'Detect the technology stacks of up to 25 websites in one call.' It clearly distinguishes itself from the compare_stacks sibling by noting batch detection versus side-by-side comparison, and from lookup_tech_stack by explicitly framing this as the multi-URL version.

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?

It gives explicit when-to-use guidance: 'when working through a list of prospects, competitors, or portfolio sites.' It also names an alternative and the condition for choosing it: 'If you want a side-by-side view of who uses what, use compare_stacks instead.'

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