Draw an axis-aligned rectangle from two opposite corner coordinates, creating four nodes and four segments; add a block label afterward to define the region.
Axis-aligned rectangle with opposite corners (x1,y1), (x2,y2): 4 nodes + 4 segments. Add a block label inside it afterwards (femm_add_block_label).
| Name | Required | Description | Default |
|---|---|---|---|
| x1 | Yes | ||
| x2 | Yes | ||
| y1 | Yes | ||
| y2 | 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 provided, so the description carries the full burden, but it does disclose a meaningful side effect: the tool creates exactly 4 nodes and 4 segments. It omits units, whether an open document/session is required, and what happens with degenerate coordinates.
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?
Two tight sentences with the geometry definition front-loaded and the follow-up action second. Nothing is redundant.
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 simple 5-parameter drawing tool with no output schema and no annotations, the description covers geometry, side effects, and the next workflow step. It could still note coordinate units and session/document prerequisites.
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 clarifies that (x1,y1) and (x2,y2) are opposite corners, which the bare titles X1/X2/Y1/Y2 do not convey, but it never mentions the optional 'session' parameter (default 'main').
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 ('Axis-aligned rectangle with opposite corners (x1,y1), (x2,y2)') and adds the resulting geometry ('4 nodes + 4 segments'), which distinguishes it from siblings like femm_draw_polygon or femm_draw_polyline that could also enclose a rectangle. It stops short of explicitly naming which sibling to use instead.
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 second sentence gives a real workflow cue: add a block label inside it afterwards via femm_add_block_label. However, there is no when-not guidance and no contrast against the other draw_* tools, so usage is implied rather than specified.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.