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

Annotations already declare readOnlyHint=true, openWorldHint=true, and idempotentHint=true, so the safety profile is covered. The description adds genuine behavioral value beyond that: it discloses that og:image is actually fetched to confirm it loads (an outbound network side effect beyond the main URL), that it reads static HTML the way directory scrapers and link-preview bots do, and that it detects JS-empty pages. These are useful non-obvious behaviors an agent could not infer from annotations alone.

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 main purpose is front-loaded, and the description is dense with information rather than padded. The long enumeration of checks is justified because it conveys the audit scope precisely and lets an agent match it to user intent. Slightly long as a single paragraph, but every clause earns its place.

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 single-parameter tool with a rich output schema and safety annotations, the description is complete: it states the purpose, the full audit scope, the return shape (score, verdict, fix), and the reading behavior. Since an output schema exists, the description need not detail return fields, and the annotations cover the read-only/idempotent safety profile.

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 coverage is 100% and the schema already documents 'url' as the Homepage URL with the https:// prefix optional. The description reinforces that the URL should be a homepage and implies the audit targets that URL, but it adds no new format, constraint, or meaning beyond the schema. Baseline 3 is appropriate.

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 opens with a specific verb+resource pair ('Audit a product homepage before launching it') and then enumerates a concrete checklist (HTTPS, noindex, meta, og:image, canonical, etc.), leaving no doubt about what the tool does. None of the sibling tools (check_badge, get_listing, submit_project, etc.) perform auditing, so the scope is clearly differentiated.

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 phrase 'before launching it' gives clear usage context and timing. However, it does not name alternatives or state explicit when-not-to-use conditions. Since no sibling tool is a close substitute, the absence of explicit exclusions is acceptable, placing this at clear-context-without-exclusions rather than full alternative routing.

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