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

Annotations already carry readOnlyHint=false and destructiveHint=true, and the description adds a useful cost side-effect: 'Consumes 5-20 CalmSEO credits depending on the result limit.' It does not explain what destructive behavior might occur beyond credit consumption, but it does not directly contradict the annotations.

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?

The description is short and mostly front-loaded: the core function comes first and the cost warning is a useful second sentence. The grammatical issue in the first sentence hurts clarity slightly but does not hurt conciseness or structure.

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 7 parameters and no output schema, the description leaves significant gaps: no pagination/ordering details, no explanation of item_types or historical_serp_mode, and no sense of the response shape. The credit-cost disclosure is helpful but not enough for a tool of this complexity.

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 only 43%, so the description needed to compensate. It only adds meaning for the 'limit' parameter by linking it to credit consumption; item_types, historical_serp_mode, and offset remain unexplained in both the schema and the description.

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?

The description names the resource (keywords a domain ranks for in Google) and the target shape (domain, subdomain, or URL), which is specific enough to distinguish from keyword-idea or search-volume tools. It lacks a crisp imperative verb and does not explicitly contrast sibling tools, so it misses a 5.

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 implies the core use case: look up the Google keywords a specific domain currently ranks for. It gives no explicit 'use this when...' guidance and never names alternatives or exclusion conditions, so it only reaches the implied-usage level.

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