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

Annotations already declare readOnlyHint, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuinely new behavioral facts: no script execution, no network access, and deterministic output. It stops short of stating failure behavior on malformed or empty HTML.

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 single sentence naming the operation and its outputs, with the constraint clause trailing. 'Free, no signup, deterministic' is partly promotional filler, though 'deterministic' has real behavioral value.

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?

With no output schema, the description correctly enumerates the returned fields, which is the most important thing an agent needs. It is adequate for a stateless one-input transform, with minor gaps around error handling and HTML size/encoding limits.

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 0% and the single 'html' property is undocumented, so the description carries the load. 'Supplied HTML' usefully disambiguates the parameter as raw markup rather than a URL, which is the main ambiguity for a one-param extractor.

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?

Specific verb ('Extract') plus an enumerated resource set (page title, meta tags, headings, JSON-LD) scoped to supplied HTML. This cleanly separates it from any sibling that fetches or cleans URLs, and an agent knows exactly what comes out.

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?

'From supplied HTML without browsing or executing scripts' effectively states the precondition: you must already hold the markup, and this is not a fetcher. No sibling alternative is named and there are no explicit exclusion cases, but the usage context is unambiguous.

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