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

The description adds significant behavioral detail beyond the readOnlyHint annotation: a new workspace sees zeros rather than an error, and the unlimited flag changes whether credit checks or purchases are necessary. These are exactly the edge cases that a caller needs to know and that are not present in the schema or annotations.

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?

The description is front-loaded with the return concept and fields, then adds pricing, the zero-state behavior, and the unlimited caveat. Every sentence earns its place, and none of the detail is redundant with the schema or annotations.

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?

With no output schema and no parameters, the description carries the full explanatory burden. It covers what is returned, the credit consumption model, the new-workspace zero behavior, and the unlimited case, making the tool safely callable and interpretable.

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?

There are no parameters and the input schema has no properties, so the baseline is 4. The description adds useful context about what credits are used for and pricing, but there are no parameter meanings to document.

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 and resource: 'Returns the workspace's credit wallet' and enumerates the exact fields returned (available, reserved, lifetime granted/used, monthly grant). It is immediately distinguishable from siblings like purchase_credits and list_credit_transactions because it is framed as a balance/status read, not a purchase or transaction history.

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 gives clear context about when checking or buying credits matters: credits pay for prospect reveals and AI work, and if unlimited is true there is 'no need to check the balance or buy credits.' It does not explicitly name alternative tools or list exclusions, but the usage context is strong enough to guide an agent.

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