Render a .jww drawing or a region to PNG for visual inspection. Zoom to a bounding box or isolate a layer group to see architectural details clearly.
Render a .jww (or a region of it) to PNG and return the image. bbox = [min_x,min_y,max_x,max_y] in real mm to zoom; lg to show one layer group only. Use this to see the drawing.
| Name | Required | Description | Default |
|---|---|---|---|
| lg | No | ||
| bbox | No | ||
| path | Yes | ||
| out_png | No | ||
| width_px | No | ||
| show_text | No |
Changes observed during successful MCP inspections.
v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden. It does disclose the meaningful behavior: the tool returns an image, bbox is in real mm and zooms, lg restricts to one layer group. It says nothing about permissions, whether out_png writes a file to disk, or whether the operation mutates anything, so a full transparency credit is not earned.
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 tight clauses, front-loaded with the core action, then the two pieces of non-obvious parameter semantics, then a one-line usage cue. No filler sentences; every clause carries information.
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?
A 6-parameter render tool with no annotations, no output schema, and 0% schema coverage needs the description to fill more gaps. Return-value guidance is adequate ("return the image"), but out_png, width_px, and show_text are left entirely for the agent to infer.
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% across 6 params, so the description must compensate. It explains the two non-obvious ones well — bbox's coordinate order and mm units, and lg's layer-group meaning — but says nothing about out_png (which implies a file write), width_px, or show_text, leaving half the parameters undocumented in both places.
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+output: render a .jww (or a region) to PNG and return the image. That is clearly distinguishable from lookup siblings like jww_info and jww_query. It stops short of explicitly naming an alternative sibling, so it is clear but not sibling-differentiated.
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?
"Use this to *see* the drawing" gives implied usage and subtly signals the visual-vs-textual split with siblings. There is no explicit when-to-use vs when-not, and no named alternative (e.g. drawing_preview or gaihen_preview) for the agent to route between.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.