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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds the cost information ('Premium API. Cost: $0.25 USDC via x402') and details the categories returned, which is useful behavioral context beyond annotations. No contradiction.

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 sentences with zero waste. The first sentence front-loads the core purpose and enumerates the returned categories; the second states cost. Every word earns its place, and the structure is immediately scannable.

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 single-parameter tool with annotations covering safety and idempotency, and no output schema, the description fully covers what the tool does, its input, its output categories, and its cost. Nothing an agent needs to call it 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?

Schema description coverage is 100%: the single 'lookup' parameter has a clear description ('Domain name or company website to identify the tech stack for'). The tool description reiterates this but adds no new semantic detail beyond the schema. Baseline 3 is appropriate given full schema coverage.

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 identifies the complete technology stack from a domain lookup, enumerating specific categories (CMS, frontend, backend, hosting, CDN, etc.). This verb-resource pairing is precise and differentiates it from the sibling tools, which mostly handle matching, verification, and information lookup for other domains.

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 implies when to use it (need to discover a company's tech stack) and includes the required input type (domain name/website). It does not explicitly name alternatives or exclusions, but given its unique purpose among a large sibling set, the usage context is clear enough. A named alternative is not necessary here.

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