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

Annotations already declare readOnly/openWorld/idempotent/non-destructive, so the bar is lower. The description adds genuinely non-obvious context: billing is 'per 10 results of depth', tying cost to the depth parameter, and the schema notes the latency tradeoff. Auth requirements and failure modes are still unstated.

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 compact sentences: what you get, the optional rank-check mode, and the cost model. No filler and the primary purpose is front-loaded.

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 adequately by listing the result fields and SERP feature types. Cost is covered; only edge cases like empty results or error behavior are absent, which is minor for a read-only search tool.

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%, so baseline is 3. The description goes beyond the schema by explaining the outcome of target_domain (that domain's best position, i.e. a rank check) rather than just 'domain to find in the results', and by linking billing to depth.

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?

Names a specific verb+resource ('Live Google organic results for one keyword') and enumerates the returned fields (position, title, URL, domain, snippet) plus SERP features. This clearly separates it from youtube_search and keyword_metrics among the siblings.

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 description explains the optional target_domain mode ('get that domain's best position (rank check)'), which is real usage guidance for one parameter. However, it never states when to pick this over keyword_metrics or ranked_keywords, nor any exclusions or prerequisites, leaving sibling selection to inference.

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