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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds a clear 'Safe, read-only validation tool. No file modifications' statement, which reinforces the annotation without contradicting it. It doesn't add much beyond the annotations, but the explicit 'No file modifications' is useful context.

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 compact and front-loaded with the core purpose, followed by clearly labeled usage and behavioral sections. Every sentence earns its place, and the structure makes it easy for an agent to parse.

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 single-parameter read-only validation tool, the description covers purpose, usage boundaries, and safety. It doesn't describe the output format, but there is no output schema and the tool is simple enough that an agent can infer the validation result. The only minor gap is not describing what the return value looks like, but this is not critical for a validation 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%, so the schema already documents the single 'target' parameter. The description adds context about what the target is used for (inspecting structured data) but doesn't add new semantic detail beyond the schema. Baseline 3 is appropriate.

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 ('Extracts and validates') and a specific resource ('Schema.org JSON-LD structured data'), and enumerates the supported schema types. It clearly distinguishes this from sibling audit tools by naming the exact data format and validation focus.

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 explicitly states when to use the tool ('Use to inspect whether structured data is correctly embedded...') and when not to use it, naming the alternative tool ('seo_generate_code_fix') and the parameter to use. This is exactly the kind of routing guidance an agent needs.

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