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

With no annotations provided, the description carries the full burden. It implies credit consumption via the price list, but does not disclose auth requirements, irreversibility, error behavior, or side effects beyond spending.

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 a single concise sentence, though the embedded JSON-like map is slightly awkward. The core action is clear, but the pricing block could be formatted more cleanly.

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 4-parameter tool with no output schema and no annotations, the description is too sparse. It does not explain 'units', prompt usage beyond the schema, prerequisites like token balance, or expected outcomes, leaving important gaps.

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 description adds a cost mapping for each service, enriching the 'service' parameter beyond the bare enum. However, it includes 'hop' which is not in the enum, and leaves 'units' undefined, only partially compensating for the 50% schema coverage.

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 clearly states a specific verb ('Spend') and resource ('AGC') with the purpose of using platform services, backed by a price list. It is distinguishable from siblings like purchase_credits or transfer_credits, though it does not explicitly contrast them.

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?

There is no guidance on when to use this tool versus alternatives such as purchase_credits or check_balance. The description merely states the action, leaving the agent to infer the appropriate context.

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