calculate_qfn_thermal_pad_stencil

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

Annotations already declare readOnly, idempotent, non-destructive behavior, so the safety profile is covered. The description adds meaningful engineering context (0.15–0.25mm outgassing web, 50–70% coverage envelope, >35% void limit), but says nothing about what happens when the requested coverage cannot be met with the given pad/web combination, nor what the solver actually returns.

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 front-loaded sentence that names the standard, the operation, the output form, and the failure modes it prevents. Dense with jargon but every clause carries information; no filler or repetition.

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 pure computational tool with all-defaulted parameters the description is largely self-sufficient, but with no output schema in place it leaves the return value (grid dimensions, aperture count, achieved coverage) unspecified. An agent knows why to call it but not precisely what it will get back.

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 all six parameters are documented in structured data; the description merely echoes the coverage range and web width already present. It adds no guidance on the two behaviorally important booleans (is_automotive_class3, has_unfilled_thermal_vias), so the schema-does-the-work baseline of 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 and resource: an IPC-7093A/IPC-7525A solver that converts solid 100% paste openings on QFN/BTC thermal slugs into a window-pane matrix grid. The domain restriction (thermal slug only) clearly separates it from the generic sibling calculate_stencil_aperture_ratios.

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 establishes a clear situational context: apply it when a solid thermal-slug opening risks voiding, die floating, or perimeter bridging. It never names an exclusion or points to a sibling (e.g., generic aperture-ratio or paste-volume tools) for non-thermal apertures, so a small amount of routing is left to inference.

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