pcb_set_plane_net

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

No annotations are provided, so the description carries the full burden and does so thoroughly: it discloses the write route, the read-back verification, the fallback path, and the failure contract ('success: false', 'applied: false', board NOT marked changed). Error codes NOT_A_PLANE and UNKNOWN_LAYER and the no-silent-retarget guarantee are exactly the behavioral context an agent needs for a mutation.

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 core action is front-loaded in the first sentence, and the structure moves logically from semantics to prerequisites to write/failure behavior. It is somewhat verbose with the negative-layer exposition and parenthetical asides, though each element is genuinely useful.

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 2-param mutation with no annotations, everything an agent needs is present: prerequisites, error cases, name-resolution rules, write/failure semantics, and return keys. An output schema already exists, so the explicit Returns section is slightly redundant but not harmful.

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 0% (both params are bare), so the description must compensate and does: it explains layer name resolution ('Internal Plane 1' as printed by pcb_get_layer_stackup and 'InternalPlane1' both work, unknown names refused), and constrains net to an existing board net. This adds meaning well beyond the empty schema titles.

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 ('tie an internal plane layer to a net') and immediately qualifies what a plane layer is. Crucially, it names the sibling it is NOT (pcb_place_polygon_rect) and explains why, so an agent can disambiguate 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?

Gives explicit when-to-use ('make Internal Plane 1 the PGND plane'), when-not (pouring a polygon on a plane layer), and prerequisites (the net must already exist, see pcb_get_nets; the layer must be an internal plane or NOT_A_PLANE). Alternatives and conditions are fully spelled out.

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