calculate_fiducial_layout

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds meaningful domain context beyond that: the governing standards (IPC-2221B Section 12, JEDEC J-STD-020), the geometric rationale (L-shape asymmetry for 180° rotation disambiguation), and the two output fiducial classes. It does not describe the returned structure, but with no output schema and clear annotations this is still strong.

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 with the generation action front-loaded and no filler. It is somewhat packed with clause-level detail, but every clause (shape, rotation rule, local fiducials, standards) earns its place.

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 read-only deterministic layout generator with full schema coverage and no output schema, the description supplies the standards, the two fiducial classes, and the geometric invariant an agent needs. Only a note on what the tool returns would make it fully complete.

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 every parameter (width, height, edge clearance, fine-pitch components, pitch threshold) is already documented in the schema. The description contextualizes fine-pitch components and local fiducial triggers but adds no syntax, units, or format meaning beyond what the schema provides, so the 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?

Precise verb+resource ('Generate ... fiducial layout') with concrete specifics: asymmetric 3-point global fiducials (L-shape, rotation-unambiguous) plus 2-point local fiducials for fine-pitch parts. It is the only fiducial tool among the siblings, and the description makes its scope unmistakable without opening the 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 when the tool applies (you need an optical fiducial layout for a PCB, with local fiducials when fine-pitch parts exist), but there are no explicit when/when-not statements or named alternatives. There is no direct sibling to route against, so implied usage is adequate but not strong.

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