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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description adds value by enumerating exactly what the call reports (credits, plan, rate limit) and framing it as a pre-flight check. It does not discuss auth requirements or rate-limit effects on this call itself, which keeps it below a 5.

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 tightly packed sentences: the first declares what is returned, the second declares when to call it. Nothing is redundant and the most important information leads.

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 simple zero-param read tool with no output schema, the description enumerates the returned fields well enough that an agent knows what it will get back. Annotations cover the safety profile, so nothing needed for correct invocation 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?

The tool takes no parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. Schema coverage is 100% and the empty object schema matches reality.

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 (check) plus the exact resources returned: remaining credits, plan, and rate limit, scoped to the connected MCPScraper API account. This is clearly distinct from the sibling get_page_contents, which fetches content rather than account metadata.

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 before large batches of fetches" gives an explicit trigger condition that tells the agent when this tool earns its call. It stops short of naming a when-not case or pointing at an alternative, but for a zero-param diagnostic tool the guidance is clear and actionable.

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