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

With no annotations, the description carries the full burden. It does disclose a genuinely valuable behavioral trait — credit cost per mode (1/2/3) — but says nothing about auth requirements, whether the call is read-only, rate limits, or that results reflect live web data. Disclosing cost alone leaves meaningful behavioral gaps.

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 short sentences, zero filler, and the core action is front-loaded ahead of the cost detail. Every clause earns its place.

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 5-parameter tool with no annotations and no output schema, the description is adequate but thin: parameters are covered by the schema, yet the agent gets no sense of return shape (raw links vs synthesized answer) or how this differs from the many sibling search-ish tools. Minimum viable rather than complete.

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%, so the baseline is 3. The description goes slightly beyond the schema by mapping each mode value to its credit cost, which directly informs the mode parameter tradeoff — a real addition even though country, freshness, and num_results are left entirely to 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 (search) and resource (the web) and names the three selectable modes (SERP, AI synthesis, both). However, it gives no differentiation from plausible siblings like research, scrape, or site-intel, so an agent cannot tell from the description alone why it would pick this tool over those.

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?

The cost-per-mode line gives an implicit decision rule (cheaper raw SERP vs pricier synthesis), which is useful. But there is no explicit when-to-use/when-not guidance and no pointer to the overlapping siblings (research, scrape), leaving mode/alternative selection to inference.

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