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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true and destructiveHint=false, so safety and idempotency are covered without description help. The description adds two useful facts beyond that: findings always come with a concrete fix, and the call is meant to run pre-handoff. It says nothing about how a URL is fetched, failure behavior on unfetchable pages, or cost/latency, which is a real but modest gap for an open-world read tool.

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?

Verb and resource are front-loaded in the first clause, and the pattern list, while long, is composed of specific named tells rather than filler. The closing sentence about fixes and the timing instruction are short and each carries a distinct instruction, though the middle enumeration could be tightened.

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 carries the return-value burden and does state that every finding includes a concrete fix, which is the key output contract. It also names the categories checked, so the agent can predict what comes back. It stops short of describing the finding structure or what happens when neither url nor html is supplied for a zero-required-param 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 100%, and the two params (url, html) are already self-explanatory in the schema. The description's phrase 'if not fetching a URL' loosely echoes the url-vs-html mutual relationship but adds no new constraint, precedence, or format detail. Baseline 3 applies when the schema does the work.

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?

States a specific verb ('Check') and resource ('a page's HTML/CSS/copy/interaction') and enumerates the concrete pattern categories it looks for, so the agent knows exactly what class of review this performs. It never names check_code or check_copy, though, so the boundary against siblings that clearly overlap with the code and copy portions is left for the agent to infer.

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?

Gives an explicit trigger: 'Call this before presenting UI to a human,' which tells the agent the moment in the workflow when this belongs. It offers no when-not guidance and names no alternative, so routing against check_code/check_copy when only code or only copy is in scope remains unstated.

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