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

Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false, so the safety profile is covered. The description adds genuinely new context the annotations cannot convey: the request is live-billed and the result reports credits charged, which is essential for a cost-aware agent calling a paid tool.

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 tight, front-loaded sentences: the capability comes first, then tier selection, then billing disclosure. No filler, though the effort sentence sits awkwardly against the competing mode enum and could be sharper.

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 19-parameter tool with nested objects, legacy-retained fields, and a required-dependent-parameter relationship (outputSchema requires effort), the description is far too thin. It leaves an agent unable to decide between this and router_web_search, and says nothing about the credit-ceiling parameter that governs the very billing it advertises.

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?

With roughly 47% schema description coverage across 19 parameters, the description needs to compensate, and it does not. It only names the effort tiers (light/medium/heavy), and it conflates this with 'mode' by saying 'choose light, medium, or heavy effort' when mode uses a separate fast/balanced/comprehensive enum; maxCredits, maxResults, topic, recencyDays, domain filters, and the legacy rails/strategy fields go entirely unaddressed.

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 outcome: a grounded, current answer with inline source references, which distinguishes it from web_extract's raw-page retrieval. However, it never differentiates itself from the sibling router_web_search, which an agent would plausibly consider interchangeable, so sibling disambiguation is missing.

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?

Offers effort-tier guidance (light/medium/heavy) which implies when to reach for a heavier, more expensive run, but gives no explicit when-not conditions and no routing advice against router_web_search or web_extract. Usage is only implied, not stated.

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