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

Annotations already mark the tool as read-only and idempotent, and the description adds a valuable non-obvious caveat: embedded ^GF/~DG image data is NOT scaled, and the response says so instead of silently passing it through. This is exactly the behavioral context an agent needs beyond the structured fields.

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 sentences front-load the action and immediately highlight the most important exception. There is no filler or repetition, and the image-data caveat earns its place by preventing a silent data-loss misunderstanding.

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?

The description adequately covers what is scaled and what is not, but with no output schema it never explicitly states the return format beyond 'the response says so'. The '(203/300/600 DPI)' list also omits 152 even though the schema accepts it, leaving minor ambiguity about supported conversions.

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 coverage is 100%, and the input schema already documents 'zpl', 'source_dpi', and 'target_dpi' with enums and meanings. The description adds general behavior but little parameter-specific meaning, so the schema carries the semantic weight and the baseline 3 applies.

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 opens with a specific verb and resource: 'Rescale ZPL between printer resolutions', and further lists what gets scaled (coordinates, fonts, barcode module width, label size). This clearly distinguishes the tool from preview/validate/explain siblings, even though the parenthetical DPI list omits 152, which the schema allows.

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 use case is clearly implied: use this tool when ZPL must be rescaled between DPI values. However, there is no explicit guidance about when to prefer this over related ZPL tools, nor any stated exclusions or alternatives, so the agent must infer the routing.

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