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

With no annotations, the description carries the behavioral burden. It usefully discloses that the operation is read-only and limited to 'recent' activity with specific transaction types. However, it does not explain what 'recent' means, whether results are paginated, or whether pending/declined transactions are included.

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 sentence with no filler, front-loaded with the resource, scope, and read-only safety trait. Every word 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?

This is a simple one-parameter read-only lookup, and the description covers the resource, the transaction categories, and the read-only nature. The only notable gap is the lack of return-shape details, but the tool is simple enough that an agent can likely invoke 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 coverage is 100% and the computeApiKey parameter is already described with where to find it and which scopes are needed. The description only adds a light link between the key and 'the wallet behind a compute API key,' which is minor supplemental context.

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 the resource ('Cloud credit activity for the wallet behind a compute API key') and scopes it to charges, top-ups, and refunds. It distinguishes it from a generic balance lookup, though it lacks an explicit verb like 'list' or 'get.'

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 context: this is recent, read-only activity for the wallet tied to a compute API key. It does not explicitly say when to choose this over the closely related sibling cloud_credit_balance, nor does it mention any exclusions.

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