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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description adds genuinely useful context beyond them: the output is a rendered image with two specific views and colour-coded move types, and that the call costs nothing — a meaningful distinction from credit-consuming siblings like generate_gcode.

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?

A single sentence, front-loaded with the action and output, with the parenthetical detail and cost note placed efficiently. 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 one-parameter read tool with no output schema, the description covers purpose, return format, and cost well. It omits prerequisites (e.g. that the job must have completed g-code generation) and behavior when the job is not ready.

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?

The schema has one parameter, job_id, with 0% description coverage, so the description carries the burden. It implies the job must be finished ('finished tool path') but never explains what job_id refers to or where to obtain it, leaving a real gap for a low-coverage 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?

States a specific verb and resource ('Show the finished tool path as an image') and even specifies the rendering (top and isometric views, cutting moves vs rapids in different colours). This is clearly distinguishable from siblings like generate_gcode or get_job_status.

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?

Gives a clear usage context: the user should sanity-check the job before paying, and the call is free. It does not name an alternative tool or state when not to use it, so it falls short of full routing guidance.

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