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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, so the description's added value is elsewhere: robots.txt is honored, some sites refuse automated readers, and those failures return a reason and cost nothing (a billing/retry-relevant fact an agent cannot infer from structured fields). No return format or rate-limit detail beyond that, so not a 5.

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?

Three short sentences, densely packed and front-loaded with what the agent gets back, followed by the scoping constraint and the failure mode. No filler.

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?

With no output schema, the description carries the return-value burden and does so: markdown body, title, final post-redirect URL, optional schema.org data. Truncation is covered by the schema. Missing only marginal detail like rate limits or size limits beyond max_chars.

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% – both url and max_chars, including the default of 20000 and the truncated flag, are fully documented in the schema. The description adds no parameter-level meaning, 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?

States a specific verb+resource: fetches any public web page or PDF and returns clean markdown, title, final URL after redirects, and schema.org data. That is concrete and distinguishes it from lookup-style siblings. It does not, however, differentiate from the sibling extract_page, which appears to overlap heavily.

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 only implied: read a page when you need its contents as markdown. There is no explicit when-to-use/when-not guidance and no mention of when to prefer extract_page or other siblings, which is the most likely agent confusion here.

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