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

Annotations already cover readOnly/openWorld/destructive, but the description goes well beyond them: live fetch semantics, 3-6 second latency, paywall limitation, paid-per-call via x402, and the important billing behavior that a timed-out read fails without charge. That is exactly the operational context annotations cannot express.

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?

Information is front-loaded: what it produces first, then latency, then fetch caveats, then routing to page.extract, then cost/failure semantics. Every sentence carries distinct, actionable content with 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?

Despite an output schema existing, the description still summarizes the return shape, and it covers the one risk an agent cares about for a paid, live-fetch tool (unreadable pages and non-charged failures). Nothing needed to invoke it correctly is missing.

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 100% for the single url parameter, so the baseline is 3. The description adds genuinely useful usage semantics beyond the schema by specifying that the address must be the specific page rather than a home page, which is a selection constraint not encoded in the schema.

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 (condense/summarize) and resource (one public web page) with quantified output shape (80-word summary, up to 4 key points, {url, summary, key_points}). It also explicitly distinguishes itself from the sibling page.extract, so an agent can route correctly without opening either schema.

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?

Gives explicit when-to-use ('Pass the address of the specific page, not a site's home page') and names the alternative for a different need ('Use page.extract for the page's own text'). It also states the failure condition (pages behind login/paywall may return little), which is real selection guidance.

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