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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety needs no restating. The description adds real behavioral context the annotations cannot: the repair is priced by the hours it buys before the next major event, and the method is documented at a specific URL. It stops short of saying what the returned decision or numbers look like, which matters somewhat since no output schema exists.

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?

Four sentences that are front-loaded with the decision, then the pricing logic, then the two input patterns. Every sentence carries information; the URL reference is the only slightly self-serving element but it substantiates the method.

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 13-parameter analytical tool the description covers the two things an agent could plausibly get wrong: which replacement figure to supply and how rebuild differs from repair. The remaining gap is that with no output schema, the shape of the returned verdict and figures is never described.

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%, so the 13 parameters are already documented and baseline would be 3. The description goes beyond the schema by explaining the relationship between replacement_cost_per_hour and replacement_price (give either) and the rebuild input pattern, which the schema lists as independent fields without stating they are mutually exclusive routes.

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 decision ('decides whether to repair (or rebuild) a machine or replace it') plus the criterion ('by comparing cost per hour'), so the agent knows exactly what it gets. It doesn't explicitly differentiate itself from the similar-sounding sibling equipment_cost_per_hour, which is the one confusion risk.

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 concrete usage conditions: supply the replacement 'either as a cost per hour or as a purchase price', and for a rebuild 'enter the rebuild cost and the much larger hours it buys'. That resolves the main input-selection ambiguity, though it never names an alternative tool or a case where you should not use it.

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