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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered by structured data. The description adds that this is a quota/plan check tied to the connected account and implicitly cheap to call, but says nothing about auth requirements, freshness of the numbers, or failure modes. Useful but not rich beyond 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?

Two short sentences: the first front-loads what is returned, the second front-loads when to call it. No filler, no restatement of the title.

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 zero-parameter read-only status tool with annotations covering safety and no output schema, the description says enough to call it correctly and covers the returned fields at a high level. It stops short of stating units or what happens when credits are exhausted, which would fully close the loop.

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 zero parameters, so there is no parameter semantics to explain; the description correctly describes the call as taking no input. Baseline 4 applies for a parameterless tool.

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 concrete verb ("Check") plus the exact resources returned: remaining credits, plan, and rate limit, scoped to the connected Context Retrieval API account. An agent immediately knows what it gets back, though it does not distinguish itself from the only sibling, get_page_contents.

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?

Gives an explicit trigger condition – "Use before large batches of fetches" – which is exactly the decision an agent needs to make before spending credits. It lacks any when-not-to-use guidance or cost/latency caveats, keeping it below a 5.

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