pcb_modify_primitive

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

Annotations already declare the safety profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false), so the agent knows this is an idempotent mutation. The description adds no further behavioral detail such as auth requirements, error behavior on invalid keys, or what happens to unmentioned properties, which leaves some behavioral gaps.

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?

Front-loads the purpose, then gives a tight per-type key list, then the unit/coordinate conventions. The bulleted structure is scannable and nearly every line earns its place; only the trailing tool cross-references are slightly reducible.

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 an idempotent mutation with no output schema, the description covers the critical unknowns: the property keys per type and the coordinate/unit system. It omits return-value semantics and how partial updates behave, but annotations plus the type-key map make it complete enough to invoke safely.

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?

Although schema coverage is nominally 100%, the 'property' parameter is an open object with additionalProperties:{} and empty properties, so the schema does not document valid keys at all. The description compensates fully by enumerating the valid property keys per primitive type plus the universally supported 'primitiveLock', which is essential to call the tool correctly.

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+resource ('Modify properties of a PCB primitive') and enumerates the exact primitive types it covers, so an agent can distinguish it from the create_* siblings. It doesn't explicitly differentiate itself from pcb_modify_track, which overlaps with the 'polyline' type it lists, leaving a small ambiguity.

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?

Provides useful operating context (units in mil, canvas coordinate conventions, pointers to pcb_canvas_origin and pcb_convert_coordinates) but never states when to use this tool versus alternatives like pcb_modify_track or pcb_delete_primitives. Usage is implied rather than explicit.

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