Credits left

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

Annotations already establish read-only, idempotent, non-destructive behavior, so the description only needs to add contextual behavior. It adds that the balance is scoped to the configured API key and counts hosted checks, but says nothing about response shape or failure cases.

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?

A single sentence that front-loads the core function and contains no redundant filler. It is concise without sacrificing the key detail about API-key scoping.

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 parameterless, read-only balance check, the description gives enough to know when and why to call it, and annotations cover the safety profile. It does not describe the exact return representation, but the 'how many' wording strongly implies a numeric count.

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?

There are zero parameters, so no parameter documentation is required. The description usefully clarifies that the API key is configured externally rather than passed as input, supporting the no-parameter design.

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 a specific resource (remaining hosted checks) and scope (configured API key), and the interrogative form clearly signals a read-only quota query. This distinguishes it from siblings such as buy_credits and verify_email.

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?

There is no explicit 'use when' statement or mention of alternatives; the intended context (checking remaining quota) must be inferred from the resource type and sibling tools. The usage context is implied rather than directly stated.

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