get_credits

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

With no annotations, the description carries the burden. It discloses a key behavioral trait: 'this call is never billed.' It also clarifies it applies to 'the current API key.' It does not detail response format or error behavior, but for a zero-parameter balance check, this is reasonable.

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 states the core purpose, the second adds a valuable cost note. No filler or redundancy. Each sentence earns its place.

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-parameter tool, the description is sufficient. It states what it does and that it is free. It does not describe the return format or edge cases, but no output schema is provided, and the simplicity of the tool makes that less critical. It is complete enough for an agent to select and invoke correctly.

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 has zero parameters, and the schema coverage is 100% (empty schema). The description adds no parameter meaning because none exist. For 0-parameter tools, the baseline is 4, and the description does not need to compensate.

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 function: checking the remaining TranscriptFetch credit balance. The verb 'check' and resource 'credit balance' are specific, and this tool is distinctly different from sibling tools like get_transcript or search_videos, which fetch video data.

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 usage—you would check credits before making billed calls—but does not explicitly state when to use it versus alternatives or any exclusions. The context is clear enough for a simple utility, but it lacks direct guidance on timing or prerequisites.

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