calculate_fab_cost

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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds real value beyond that by disclosing the pricing model ('fab-house published tiered pricing') and the 'Estimate only' caveat, signaling this is an approximation rather than a binding quote.

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?

A single dense sentence front-loads the purpose and pricing basis, followed by the terse 'Estimate only.' caveat. It is tightly sized, though the enumerated parameter list partially duplicates the fully-covered schema.

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?

With annotations covering safety and the schema covering all inputs, the description supplies the remaining context (estimate source and approximation caveat). Minor gaps remain: no output schema and no mention of currency or return format, but these are not critical for a read-only calculator.

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%, so all eight parameters (including pricing multipliers for finish, color, and lead time) are already documented. The description recaps the same inputs (layers, quantity, color, finish, thickness, lead time) at a higher level without adding syntax or meaning beyond the schema; baseline 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?

States a specific verb ('Estimate') and resource ('PCB fabrication cost') and immediately scopes the pricing basis to fab-house published tiers. This clearly distinguishes it from sibling cost tools such as calculate_bom_cost, without needing to open 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?

The description implies usage (published tiered pricing) and adds the caveat 'Estimate only', but never states when to use this tool versus alternatives like calculate_bom_cost, nor any prerequisites. The guidance is inferable but not explicit.

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