Image SEO Check

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

Annotations already declare read-only, idempotent, and non-destructive behavior, so the bar for additional disclosure is lower. The description adds useful context beyond the annotations: it audits every <img> on the page, counts <picture> sources as modern delivery, and specifies the return payload. It does not contradict the annotations.

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 front-loaded with the core audit purpose and checklist, followed by clearly labeled Args, Returns, and an Example. It is structured and dense, but the Args and Returns sections are somewhat redundant with the input and output schemas, so it is not maximally concise.

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 moderately complex tool with two documented parameters, a full output schema, and strong annotations, this description is operationally complete. It explains exactly what is checked, the nuance of <picture> sources, the output structure, and provides an invocation example, leaving no critical gap for selection or correct use.

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?

The input schema already provides thorough descriptions for both url and response_format, including defaults and the https:// default for url, giving 100% coverage. The description's Args section merely restates these in abbreviated form, and the example only maps a natural-language request to a call without adding new parameter semantics.

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 the specific verb 'Audit' and names the exact resource ('every <img> on the page'), then enumerates the precise SEO checks performed (alt text, dimensions, lazy-loading, modern formats). This clearly distinguishes it from broader sibling tools like seo_audit or render_check.

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 makes the intended use obvious: it is the tool for a page-level image SEO audit, listing the exact aspects it checks and even giving an example natural-language query mapped to a tool call. It does not explicitly mention when not to use it or point to alternatives, but the context is clear and self-contained.

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