sch_add_symbol

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

The description adds useful behavioral detail beyond the destructiveHint annotation: it reveals that coordinates are snapped to a grid by default and that snap_to_grid=False is needed for intentional off-grid placement. It also clarifies the coordinate system is absolute. This is valuable context not present in the annotations, though it could also mention that the schematic is modified.

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 description is two sentences, front-loaded with the core purpose first, and the second sentence adds a single important parameter behavior. There is no wasted text or repetition of schema fields. It is concise and well structured.

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?

Given the tool has 10 parameters, a destructive hint, and an output schema, the description covers the tool's essence and grid-snapping quirk but does not explain the meaning of several required parameters (library, symbol_name, reference, value). The output schema exists but the description does not clarify how it is returned, though that is not required. It is mostly sufficient for a narrow placement task but lacks depth for complex usage.

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?

The input schema has no parameter descriptions (0% coverage), so the description must compensate. It does explain x_mm, y_mm, and snap_to_grid behavior, but leaves the other 7 parameters (library, symbol_name, reference, value, unit, rotation, footprint) without any semantic guidance. For a tool with 6 required parameters, this is a significant gap.

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 description uses a specific verb ('Add') and an explicit resource ('schematic symbol') with a location ('at an absolute coordinate'). It clearly distinguishes this from sibling tools like sch_add_wire or sch_add_power_symbol, which add different object types.

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 provides a clear context for grid snapping ('snap to the 2.54 mm schematic grid by default') and instructs when to override it ('only when an exact off-grid coordinate is intentional'). However, it does not explicitly mention when to use this tool over alternatives, such as sch_create_sheet or sch_add_label, nor does it state any exclusions or prerequisites like a loaded library.

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