Add nodes at specified [x,y] points in a FEMM model for custom geometry; existing nodes at the same location are reused, so use polygon or segment tools when possible.
Add nodes at [[x, y], ...] (problem units; axi: x is r >= 0). Existing nodes at the same place are reused by FEMM. Usually you want femm_draw_polygon / femm_add_segments instead.
| Name | Required | Description | Default |
|---|---|---|---|
| points | Yes | ||
| session | No | main |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are supplied, so the description carries the full burden. It does disclose a genuinely non-obvious behavioral trait — 'Existing nodes at the same place are reused by FEMM' (effective dedup), plus units and coordinate-system constraints. It omits what is returned (node handles/indices), whether the session must be open, and any error behavior.
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?
Three short clauses, each load-bearing: format/units first, then the reuse behavior, then the alternative-tool routing. No filler and everything an agent needs is front-loaded.
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 no-annotation, no-output-schema creation tool the description is adequate but not complete: it omits the undocumented 'session' parameter and gives no hint of what the call returns (node identifiers), which an agent would need to follow up with femm_set_node_prop.
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 compensate. It documents the required 'points' parameter well (nested [[x,y]] pairs, problem units, axi semantics) but never mentions the 'session' parameter, leaving half the inputs unexplained in both schema and description.
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 ('Add nodes') and immediately pins down the input format '[[x, y], ...]' plus problem units and the axi constraint (x is r >= 0). It also distinguishes itself from nearby siblings by naming femm_draw_polygon / femm_add_segments as the usual choice, so an agent can route without opening schemas.
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?
Explicitly tells the agent when NOT to use it ('Usually you want femm_draw_polygon / femm_add_segments instead'), which is stronger than most siblings. The positive condition (standalone points not tied to a segment/polygon) is only implied rather than stated, so it falls just short of full when/when-not coverage.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.