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

Annotations already declare destructiveHint=true and idempotentHint=true, but the description supplies the concrete meaning: passing an empty value or 0 wipes the existing total. That tells the agent exactly what the destructive path is, which the hints alone do not. It does not describe any permission requirements or downstream effects on category budgets.

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?

Three short sentences, front-loaded with the primary effect, then the removal rule, then the sibling routing. Every sentence carries distinct information and nothing is padded.

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 one-parameter mutation tool with rich annotations, the description covers the core behavior, the deletion path, and the related-tool boundary. The only gap is the absence of any note on side effects (e.g., whether category budgets are recalculated), which is a small omission given how simple the operation is.

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% for the single parameter and the schema already documents euro formatting and "empty to remove," so the description is mostly restating it. It does add "0" as an additional removal trigger beyond the schema's stated empty value, but that is a minor increment over structured data that already does the heavy lifting.

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?

States a specific verb and resource ("Sets the total budget of the wedding") plus the scoping semantics ("the amount the couple wants to stay under"), and explicitly distinguishes itself from update-budget-category, which handles per-category planned amounts. An agent can route correctly without opening either schema.

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?

Gives a clear operating condition (empty value or 0 removes the budget) and names the alternative for a closely related task (per-category planned amounts via update-budget-category). It stops short of explicit when-not-to-use guidance relative to get-budget or add-budget-category, but the routing signal is unambiguous.

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