Get account & credit balance

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds useful context by specifying the account is 'authenticated' and enumerating the returned fields, giving the agent a clear model of what the call will reveal without overstating behavior.

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 with no filler. The return fields are front-loaded, followed immediately by the practical use case. Every word contributes to the agent's understanding of what the tool does and when to call it.

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 account lookup with an output schema available, the description fully covers purpose, expected fields, and typical usage. There are no hidden inputs, side effects, or pitfalls that need disclosure. Nothing an agent needs to correctly invoke this tool 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 has zero parameters, so there is nothing for the description to explain about inputs. The description focuses on output fields and usage intent, which is appropriate. The baseline of 4 applies here because no parameter documentation burden exists.

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 states a specific verb ('Return'), identifies the resource ('authenticated Rapid Indexer account'), and enumerates the exact fields returned (id, email, credits balance, created date). This clearly distinguishes it from siblings like get_pricing or estimate_cost, which address costs rather than account 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?

The description provides a clear usage cue: 'Use it to check credits before creating tasks.' This gives an agent a concrete trigger for invoking the tool. It does not explicitly name alternatives or exclusions, but the context is sufficient for this simple read-only account tool.

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