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

Beyond the annotations (readOnly, openWorld, non-destructive), the description discloses substantive behavior: evidence is bounded and static, no scripts run, MCP discovery is advertised rather than tested, WebMCP is declared but not browser-verified, and every deduction names its fix. It even defines the failure-mode contract (score is null when too little could be measured), which is exactly the kind of context 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?

The text is dense but nearly every clause carries information — evidence sources, transparency caveats, null behavior. It is slightly crammed into two long sentences rather than cleanly front-loaded, but there is minimal filler.

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-value explanation is not required, and the description covers scope, evidence boundaries, and the null-result case well. The one missing piece is sibling differentiation (check_website vs this tool, and the get_agent_readability_method companion), which an agent would still need to resolve.

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 the single hostname parameter is already fully documented in the schema (public domain, no path/port/IP). The description adds no additional parameter meaning beyond that, so the baseline of 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?

The description states a specific verb+resource: it computes an Agent Readability Score (0-100) for a website, and enumerates the exact evidence sources used (homepage HTML, robots.txt, llms.txt, discovery files, sitemap, Markdown negotiation). It is clear and concrete, but it never distinguishes itself from the sibling check_website or references get_agent_readability_method, so an agent cannot route confidently from the description alone.

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 explains what evidence is inspected but gives no explicit when-to-use, when-not-to-use, or alternative selection guidance against check_website or get_agent_readability_method. Usage is only implied by the tool's purpose.

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