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

The description thoroughly discloses the behavior: moves credits from treasury into a prepayment pool, covers the tax assessment before treasury is touched, refunds surplus, and requires a specific permission. The readOnlyHint=false annotation is consistent with the mutating nature of the tool, and the description adds significant context beyond the annotation, including the flow and purpose.

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 efficient and every sentence adds value, but the formatting uses a long parenthetical that could be split for better readability. The main action is front-loaded, and the extra details are purposeful, though the structure is slightly awkward.

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 financial mutation tool with no output schema, the description covers the action, mechanism, permission, and related estimation tool. However, it does not describe what the response contains (e.g., updated balances) or any failure modes, leaving minor gaps. Overall, it is complete enough for an agent to understand the tool's purpose and side effects.

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%, with both parameters having descriptions. The tool description mentions 'amount must be a positive number of credits,' which simply restates the schema's 'positive' and minimum:1. No additional semantic meaning is added beyond what the schema already provides, so the baseline 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 clearly states the specific action ('Prepay credits from the faction treasury toward the next corporate tax assessment') with a specific verb and resource. It distinguishes itself from sibling tools like 'prepay_tax' by emphasizing the faction treasury and corporate tax context. The mechanism is clearly explained.

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 directs the user to 'Use get_faction_tax_estimate to see the current obligation and prepaid balance,' providing a clear contextual alternative. It also states the required permission (ManageTreasury) and explains the use case (prepay to avoid being caught short). However, it does not explicitly state when not to use this tool.

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