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

Annotations already cover safety (readOnly, idempotent, non-destructive), so the bar is lower. The description adds concrete detail about what is checked (e.g., HSTS, CSP, robots.txt) and notes the 'real-time' nature, which helps the agent predict behavior beyond the schema.

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?

A single, front-loaded sentence that immediately states the purpose, then lists specific checks. Every element adds value with no redundancy, making it both concise and structured for quick parsing.

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 one simple parameter and rich annotations, the description covers the tool's scope well. It doesn't describe the output format, which would be useful, but the lack of an output schema reduces the expectation. The enumerated checks give enough context for an agent to invoke 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?

Only one parameter, 'domain', with no schema description. The name is self-explanatory, and the description reinforces that the tool targets a website. While it doesn't specify formatting (e.g., with/without protocol), the simplicity of the parameter and tool context make this sufficient.

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 a specific action ('Real-time site health check') with enumerated checks (HTTPS, HSTS, redirect behavior, response times, security headers, robots.txt). This distinguishes it from sibling tools like get_page_seo or get_tech_stack, which focus on different aspects.

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 establishes clear context for use: when needing an overall site health assessment including security headers and redirects. It doesn't explicitly name alternatives or exclusions, but the sibling list shows this is the go-to for health checks, not backlinks or GSC metrics.

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