lib_add_symbol_polygon

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

With no annotations, the description carries the full behavioral burden. It does disclose validation (minimum 3 vertices), the default 25-mil snap and how to disable it (0/1), and the return shape (confirmation with vertex count). It does not say whether the polygon is appended vs. replaces existing geometry, whether it is undoable, or that it requires an active current symbol — significant gaps for a mutation tool.

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-loaded with the action, then per-argument guidance with an inline example. The grid paragraph is slightly long for a snapping parameter, but the rule-15 justification earns its place by explaining an unusual default.

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-parameter mutation tool with no annotations but an output schema, the description covers input format, validation, default behavior, and return value. What is missing is the operational precondition (an active current symbol) and any statement about how this polygon relates to existing symbol geometry.

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%, so the description must do all the work, and it does: the vertices format, a concrete worked example, the 6-value minimum, and the meaning plus valid values of grid (default 25, 100 for coarse, 0/1 to disable) with the rationale for the non-standard default. This fully compensates for the bare schema.

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?

Clear verb + resource: adds a filled polygon of ordered vertices to the current library symbol. The parenthetical '(filled shape)' and the diode-triangle example distinguish it in spirit from lib_add_symbol_lines, lib_add_symbol_rectangle and lib_add_symbol_arc, but it never names those siblings explicitly, so the agent has to infer the routing.

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?

Usage is implied rather than stated: the glyph-detail remark and the rule-15 aside convey that this is for symbol artwork rather than pin-grid geometry. There is no explicit 'use this instead of X when Y', and no statement of the prerequisite that a current symbol must already be selected (lib_set_current_component) before calling.

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