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

Annotations already declare readOnlyHint, idempotentHint and non-destructive behavior, so the safety profile is covered. The description adds real value beyond that: 12 items, ~12 second runtime, the four possible statuses (pass/partial/fail/could_not_check), and the non-obvious scoring rule that the score covers only checkable items. It doesn't mention rate limits or whether the result is cached, which is why this is a 4 rather than a 5.

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?

Content is front-loaded: the check scope comes first, then behavior/scoring, then sibling routing, then the parameter. The middle sentence about the 12 items is somewhat dense but every clause carries information. Slightly longer than strictly necessary, but no 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?

With no output schema, the description must describe return shape and does so: a 0–100 score, per-item status, evidence, and a plain-English fix, plus the caveat about could_not_check items. Combined with the scope limits and routing guidance, an agent has everything needed to invoke and interpret the tool.

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 there is a single required 'url' parameter, so the description carries the burden. It supplies meaning the schema lacks: 'the website to check, for example https://example.com', which conveys the expected format and that a homepage URL is intended. Minor gap: it doesn't say whether protocol is required or whether subpaths are accepted.

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 and resource ('quick SEO check of any website's homepage') and enumerates exactly what is examined: indexability, title/meta, H1, canonical, mobile and speed. The scoping phrase 'homepage only, not a full SEO audit' plus the sibling toolbox (assess_website, assess_ai_readiness, assess_ad_tracking) makes it easy to distinguish from the other assess_* tools.

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?

It gives explicit scope limits ('Automated, homepage only, not a full SEO audit') and names the exact alternatives for follow-up actions: get_seo_offer for TESSA's SEO service and request_strategy_session for a conversation. An agent knows both when to call this and where to route the user afterwards.

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