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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds only that the endpoint is 'public', which is a mild behavioral trait. It does not describe rate limits, response behavior, or auth interactions beyond that, but the annotations carry most of the safety profile.

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?

One short sentence contains the action, the resource, and the endpoint. There is zero filler, and the most important distinguishing detail (the exact endpoint) is included without extra words.

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?

The tool is simple: one optional parameter, no required inputs, an output schema exists, and annotations cover the safety profile. The description's mention of the public endpoint combined with the schema and annotations is sufficient for an agent to call it 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?

Schema description coverage is 100%, and the rd_api_key parameter is already fully described in the schema as optional and overriding session/header auth. The description adds no parameter-level information, so the baseline score of 3 applies.

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 verb ('Get') and resource ('credits/balance') and pins it to the exact endpoint '/v2/inferences/credits'. This is unambiguous and, by naming the endpoint, effectively distinguishes it from other tools without needing to list siblings.

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 does not state when to use this tool versus alternatives or when not to use it. The word 'public' hints that it may not need authentication, but there is no explicit usage context or exclusion. An agent is left to infer that this is simply the balance-checking tool.

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