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

The annotations already disclose the key behavioral traits (readOnlyHint=true, idempotentHint=true, openWorldHint=false), and the description does not contradict them. The parameter descriptions add useful behavioral notes such as 'Script execution is never allowed' and parse-as-HTML-fragment behavior, but the main description itself contributes no additional transparency about side effects, safety, or operational constraints.

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 description is a single, tightly worded sentence that front-loads the core purpose (catching duplicate IDs and broken ARIA relationships) with no filler, redundancy, or extraneous detail. It is appropriately sized for a checker tool with straightforward scope.

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?

Given the rich parameter schema, the read-only/idempotent annotations, and the presence of an output schema (so return values need not be explained), the description is largely sufficient. It conveys the checking scope clearly; minor gaps exist in that it does not explicitly frame the tool as a validator/analyzer or mention the boolean toggles, but these are covered by the schema.

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% — all four parameters (html_snippet, check_duplicate_ids, check_aria_references, show_element_paths) have detailed descriptions including conditional behavior ('When true... when false...'). Since coverage exceeds 80%, the baseline of 3 applies; the tool description adds no per-parameter meaning beyond what the schema already documents.

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 conveys the domain and purpose — catching duplicate IDs and broken ARIA references in HTML — and the tool name reinforces this. It differentiates well from sibling tools, which all target unrelated domains (API diffs, badge readability, JSON contract checks). However, it is phrased as a developer need ('Developers need to catch...') rather than an explicit action statement with a direct verb describing what the tool does.

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 provides no guidance on when to use this tool versus alternatives. It does not mention suitable scenarios, prerequisites, or when not to use it, nor does it compare against sibling tools. The parameter descriptions hint at toggle behavior, but no explicit usage context is given.

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