get_credits

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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false), but the description adds genuinely new behavioral context: there is no storage quota, the library is bounded by time via `retention`, and `library.completedTranscriptions` is a bounded count where `isCapped=true` means the real value is higher than reported. That last point is important data-accuracy disclosure an agent could not infer from the schema.

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?

Front-loads what the tool returns, then adds two short clarifying notes about cost and library capping. Four sentences with no filler, though the backticked field references (`retention`, `library.completedTranscriptions`, `library.isCapped`) get dense for a short description.

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?

There is no output schema, so the description carries the return-value burden, and it covers the main items (balance, tier, library counts, retention) plus the `isCapped` caveat. It does not sketch the full response shape or the format of the retention value, which is a minor gap for a simple no-arg read tool.

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 are no parameter semantics to document and the baseline of 4 applies. The description correctly does not waste space on non-existent inputs.

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) and enumerates the exact resources returned: credit balance, subscription tier, stored completed transcriptions, and retention duration. It is clearly distinguishable from the transcription-oriented siblings (transcribe_video, list_transcriptions, etc.) since no other tool exposes account/billing state.

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?

Usage is only implied: mentioning 'Each transcription costs 1 credit' suggests calling this as a pre-flight affordability check. It never states when to prefer this over siblings or any condition where it should not be called, so guidance is implied rather than explicit.

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