lib_redraw_assembly

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

With no annotations present, the description carries the full burden and does so: it discloses that 'replace' clears tracks, arcs, texts, fills and regions on the layer, that 3D bodies and pads are never touched, that 'confirm' is mandatory whenever replace is used, that the library is NOT saved, and that a disabled mechanical layer is accepted with layer_enabled false plus a warning. These are exactly the destructive/side-effect details an agent needs before invoking.

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?

The lead sentence front-loads the operation and the rest is organized as a scannable Args block, so it reads well. It runs long, and a few clauses (the text-height sizing formula, the returns field list) restate detail an agent may not need before calling, though none is genuinely wasteful.

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 10-parameter destructive library mutation, the description covers preconditions (confirm), irreversible effects (clearing the layer), failure modes (skipped/not_found footprints, disabled layer warning), and post-state (footprint re-shown, library unsaved). The Returns block slightly duplicates the output schema but leaves nothing an agent needs missing.

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 0% across 10 parameters, so the description must compensate entirely, and it does: each of layer, footprint_names, outline_from (with all four enum-like values and the auto fallback order), courtyard_layer (including the replace conflict), width, designator, text_height (default sizing rule and 0.2–1 mm clamp), replace, confirm, and units is explained with defaults and edge cases.

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?

The opening sentence gives a precise verb and resource ('Draw the assembly layer of the focused PCB library again') plus the exact output of the operation (a rectangle around the part plus a '.Designator' centered in it). An agent can distinguish this from lib_move_bodies_to_layer or pcb_copy_designators_to_mech 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?

It states the problem context that motivates the call ('libraries carry the assembly drawing on the wrong layer, from another package, or not at all'), which tells an agent when to reach for it, and it defines the replace-vs-append behavior. It stops short of naming a sibling alternative or an explicit 'do not use when' condition, so it is clear but not fully routing.

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