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

No annotations are provided, so the description carries the full burden. It implies a read-only computation but never states that it has no side effects, nor how the output is structured or how 'pixel width'/'truncation position' are computed. Only the core estimate is disclosed, which is essentially restated purpose.

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?

A single sentence front-loaded with a bracket category tag, followed by the actionable content. Efficient with no wasted words, though the bracket prefix adds little for an agent.

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 3-parameter tool with a required field, no output schema, no annotations, and 0% parameter coverage, one sentence is insufficient. It omits the url parameter's role, what the estimate returns, and any caveats about estimation accuracy.

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%, so the description must compensate. It references 'title' and 'description' implicitly, but never explains the 'url' parameter or the required/optional status, and adds no format constraints (e.g. length limits) beyond the schema field names.

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 and resource: previews a Google SERP title/description and estimates Chinese pixel width and truncation. It is distinguishable from siblings like generate_meta_tags (which authors tags) versus this preview tool, though it does not name any sibling explicitly.

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?

No when-to-use/when-not guidance and no routing to alternatives. The closest sibling, seo__generate_meta_tags, is never mentioned even though previewing versus generating are easily confused; usage is only implied by the phrase 'preview'.

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