calculateCreditOperation

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

Annotations already indicate readOnlyHint=true, and the description reinforces this by stating 'without moving any credits.' It further adds behavioral context by warning that 'The response shape differs between forward transfers and reverts,' which is not present in annotations. The mention of examples is somewhat vague but still provides additional guidance beyond the structured data.

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 compact, four sentences, with no redundant phrasing. It front-loads the core purpose in the first sentence, then provides usage guidance and a caveat. Every sentence contributes meaningful information; 'See the examples' is brief and acceptable. This is appropriately concise and well-structured.

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 has no output schema, so the description carries the burden of explaining return behavior. It does state that the response shape differs between forward transfers and reverts but does not describe what the response contains or how it differs. Pointing to examples is not a substitute for concrete detail in the description. For a preview tool, more completeness about the returned data would be expected.

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%, so the schema fully documents every parameter (minutes, is_revert, cost_per_min, child_organization_id). The description does not add any parameter-specific semantics beyond what the schema already provides—it only mentions general operation types and response shape. This meets the baseline but does not exceed it.

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 identifies the tool as a preview action ('Preview the cost of a transfer or revert without moving any credits'), which explicitly distinguishes it from the actual transfer/revert operations. It uses a specific verb ('preview') and resource ('credit operation'), making its purpose unmistakable relative to sibling tools like transferCreditsToChild and revertCreditsFromChild.

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 explicitly states when to use the tool: 'Use this to confirm amounts before calling the transfer or revert endpoints.' This names the alternative operations and sets a clear precondition, effectively guiding the agent to select this tool for cost estimation rather than execution. Though it doesn't cite exact sibling tool names, it refers unambiguously to transfer and revert endpoints.

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