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

Annotations already cover the read-only, idempotent, non-destructive profile, and the description adds genuinely new behavioral context: margin is a percentage of selling price, the calculation is currency-neutral with no conversion, no auth is needed, and the endpoint is rate limited. The rate-limit and auth disclosure is exactly the kind of extra context annotations cannot convey.

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 core action and outputs before the calculation rule and operational notes. Every clause adds information with no repetition 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?

An output schema exists, so return values need not be explained, and the description covers the key semantic rule (margin basis), currency behavior, and access/rate constraints. The main residual gap is unit/format guidance for the six undocumented numeric inputs.

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 0% across 7 required parameters, so the description carries the full burden, but it only pins down one field's semantics: margin is a percentage of selling price. The remaining six (hoursOnSite, hourlyRate, editingHours, editingRate, gearTravelCost, numPhotos) rely on self-explanatory names with no stated units or format, leaving partial compensation.

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 precise verb (Calculate) and enumerates the four concrete outputs: session price, costs, profit, per-photo price. It is unambiguous what the tool produces, though it does not explicitly differentiate itself from pricing-adjacent siblings like agency_pricing or freelance_rate.

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 gives no when-to-use guidance and never names an alternative tool. Statements like 'Free, no authentication required' describe operational properties rather than selection criteria, so the agent must infer that a photography-session quote is the right context.

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