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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the description clears the lower bar easily by adding genuinely new facts: SSRF guarding, bounded fetching, pre-payment rejection of private addresses/non-HTML/error pages, and a $0.01 cost. What it omits is truncation behavior when content exceeds max_chars, which matters for a bounded fetch.

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?

Two tight sentences, front-loaded with the verb and resource, then behavior and cost. The enumeration of returned fields is dense but earns its place given there is no output schema; nothing is redundant.

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 by listing title, author, date, canonical URL, links and metadata. Combined with the SSRF/refusal and pricing disclosure, an agent has enough to invoke it correctly; the only residual gap is max_chars truncation semantics, which the schema range partly covers.

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 coverage is 67%: url and links are documented in the schema, but max_chars has no description there and the prose does not compensate by explaining truncation or what happens at the 100000-character ceiling. The description adds essentially no parameter-level meaning beyond the schema, so the baseline 3 fits.

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 gives a concrete verb and resource ("Fetch a public URL and extract the main content as clean Markdown") and enumerates the returned fields, so the operation is unmistakable. It does not differentiate from the sibling get_page_metadata, which plausibly overlaps on metadata extraction, leaving the agent to infer the boundary.

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?

"Designed for agent research" implies a usage context, and the refusal conditions (private addresses, non-HTML, error pages) tell the agent what inputs are out of scope. However, no alternative or sibling tool is named, and there is no explicit when-to-use-this-instead-of guidance.

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