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

Annotations declare readOnlyHint/openWorldHint, and the description usefully adds behavioral context beyond them: 'Cached daily' (data freshness), the $0.01 USDC cost via x402 or prepaid credits, and the free-trial status. Cost and cache behavior are exactly the kind of details annotations cannot convey.

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?

Front-loaded with the core capability, followed by two short sentences covering freshness and pricing. Dense but each sentence carries distinct information; the category list is long but informative rather than padded.

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?

An output schema exists, so return values need not be described. Between the category enumeration, the cache cadence, and the pricing model, an agent has everything needed to select and invoke the tool correctly.

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% and both parameters already document their purpose (name improves matching, domain is the website domain). The description adds no parameter-level detail, so the baseline 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?

States a specific verb+resource ('What technology a company uses, from its website and DNS') and enumerates the detected categories (CMS, frameworks, analytics, payments, hosting/CDN, email, DNS records, social profiles). An agent can distinguish this from siblings like company-profile or dns without opening a schema.

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?

Usage is implied by the tool's nature — supply a domain, get its techstack — but there is no explicit when-to-use guidance and no named alternatives or exclusions (e.g., versus company-profile or dns). Adequate but with a clear gap.

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