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

Annotations already cover safety (readOnlyHint, idempotentHint, openWorldHint), so the description's contribution is the operational detail: it is free with no API key, and it enumerates exactly which nine schema.org types get validated, which discloses a real coverage limit an agent would otherwise not know. It stops short of stating what happens on fetch failure or when no JSON-LD is present.

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?

Front-loaded with the primary action, then the scoring detail, then the free/no-key and docs notes. It is one long run-on sentence whose clauses all carry information, but a bulleted structure would make the enumerated type list easier to scan.

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?

No output schema exists, and the description compensates by describing the returned content (extracted blocks, type list, missing-property flags, entity score). What is missing is edge-case behavior — no structured data found, unreachable page, or whether the raw HTML is parsed versus rendered output.

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?

Only one parameter with 100% schema description coverage, and the schema already explains that https:// is added when missing. The description adds no syntax, format, or constraint information beyond the schema, so the baseline 3 applies.

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?

Specific verb chain and resource: extracts JSON-LD blocks, lists schema.org types, flags missing required/recommended properties, and scores entity signals. The resource (structured data on a URL) is clearly distinct from the llms.txt and crawler-access siblings. It does not explicitly say how it relates to run_aeo_audit, which is the one sibling that could plausibly overlap.

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?

Usage is implied by the content ('check a page's structured data') but there is no explicit when-to-use statement, no prerequisites, and no routing away from run_aeo_audit or the other siblings. An agent can infer the use case but must decide on its own when this beats the broader audit tool.

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