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

Annotations already cover safety (readOnly, idempotent, non-destructive), so the bar is lower. The description still adds real value by clarifying it is a pure calculator ('does not transfer money') and that traditional assignments are etiquette, not obligations — behavioral framing not present in structured fields.

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 purpose and each sentence pulling weight (purpose, etiquette caveat, no-money clarification). No redundancy or filler.

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?

No output schema exists, but the description tells the agent what comes back in substance (percentages and amounts), and the safety profile is covered by annotations. Complete enough for a simple two-parameter calculator, though the enum model names remain unexplained.

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% with only two parameters, so the schema fully documents model and total_budget. The description only gestures at 'selected model' and never explains the enum values or budget units, adding nothing beyond the schema. Baseline 3.

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?

Names a specific verb (Calculates) and resource (percentages and amounts for dividing a wedding budget), plus the actor scope (couple and families). It is distinguishable from most siblings, though it does not explicitly contrast itself with the nearby get_budget_estimate.

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?

'under a selected model' implies the input needed, and the etiquette disclaimer gives context, but there is no explicit statement of when to reach for this tool versus get_budget_estimate or get_alcohol_estimate, nor any exclusions.

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