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

With no annotations, the description carries the full burden and does so: it discloses the retrieval scope (top 4 pages, answer restricted to them), the return shape (answer with inline [n] citations, citations array with quotes, confidence, notes), the billing outcome ('Provider or model failure is not charged'), and the price/payment rail. These are exactly the behavioral facts an agent cannot get from the schema.

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 'Use when' trigger, then input, output, behavior, billing, and price in a tight sequence with no filler. The example query and price line are useful rather than decorative, though the dense packing of input/output/price into single lines reads more like a spec sheet than prose.

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?

Two-parameter tool with no nested objects; the description covers trigger, inputs, output structure (compensating for the absent output schema), retrieval limits, and cost. Nothing an agent needs to decide to call it or to interpret the result 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 already 100%, so the baseline is 3; the description adds value by restating q as the question and enumerating the accepted time_range values (day, week, month, year) that the schema leaves as free text with no enum. That closes a real ambiguity an agent would otherwise guess at.

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 and resource: produces a sourced answer to a question from the live web, and reveals the mechanism ('searches, reads the top 4 pages itself'). An agent can distinguish it from web_search/web_read because it says the answer is written and constrained to those pages. It stops short of naming a sibling as the alternative, so differentiation is implied rather than explicit.

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?

'Use when an agent needs a sourced answer to a question from the live web in one call' gives a clear triggering condition, and 'answers only from them' implies the boundary of what it will cover. There is no explicit when-not guidance or named alternative such as web_search_read for agents who want raw pages rather than a synthesized answer.

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