Serpstat MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes key behavioral traits: it's a read-only analysis tool (implied by 'identifies'), discloses the cost model ('API cost: 1 credit per result row returned'), and explains the meaning of the weight metric in results. However, it doesn't mention rate limits, authentication needs, or pagination behavior.

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 efficiently structured with four sentences that each earn their place: purpose statement, weight metric explanation, use case context, and cost disclosure. It's front-loaded with the core functionality and contains zero wasted words.

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 complex tool with 6 parameters, nested objects, and no output schema, the description provides good contextual completeness. It explains the tool's purpose, key metric interpretation, use cases, and cost implications. The main gap is lack of output format details, but given the complexity and absence of annotations, this is a reasonable compromise.

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 schema already documents all parameters thoroughly. The description adds some value by explaining the 'weight' metric concept, but doesn't provide additional semantic context for parameters like 'url', 'se', or the various filters beyond what's in the schema. Baseline 3 is appropriate when schema does the heavy lifting.

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 clearly states the tool's purpose with specific verbs ('identifies keyword opportunities') and resources ('keywords where your competitors rank in top-20 but your URL does not'). It distinguishes itself from siblings by focusing on missing keywords for a specific URL rather than general keyword analysis or other SEO functions.

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 provides clear context for when to use the tool ('Perfect for content gap analysis and finding quick wins'), but does not explicitly state when not to use it or name specific alternative tools from the sibling list. The agent can infer alternatives from sibling names like 'get_keywords' or 'get_domain_keywords', but no direct comparison is made.

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