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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), and the description adds genuinely new context: results include supporting evidence per detection, and each successfully loaded website counts as one result (a billing/quota semantic not present in the schema). It stops short of covering auth, rate limits, or failure behavior.

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?

Two sentences, both front-loaded with the operation and then the result-count semantics; the enumeration of detection categories is informative rather than padding. No wasted clauses.

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 read-only, open-world detection tool with a fully documented 2-parameter schema, the description covers scope, output content, and result accounting. Missing only peripheral details (auth requirements, partial-failure behavior) that an agent could mostly infer.

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%, so both urls (1-20 sites) and includeDns are fully documented in structured fields. The description's mention of "email and DNS provider" detection loosely maps to includeDns but only repeats what the schema already says; 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 ("Detect") plus resource (website tech stack) and enumerates exactly which signals are returned (CMS, ecommerce, frameworks, analytics, ad pixels, hosting, CDN, email/DNS). This is plainly distinguishable from siblings like domain_whois or website_screenshot.

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 purpose statement — you call it when you want to know what a site is built with — but there is no explicit when-to-use, when-not-to-use, or routing to alternatives such as domain_whois for registration data. Adequate minimum viability, nothing more.

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