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

Annotations flag destructiveHint=true and readOnlyHint=false, so the agent knows this is a mutating, irreversible operation, but the description never explains what is destroyed—the originals, the reflection, or nothing—nor what 'merge' or 'join' do to the shape tree. For a destructive mutation, the description should describe the effect on existing shapes and add context beyond the annotations; it does not.

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 front-loaded sentence with no filler, but that brevity comes at the cost of under-specification rather than efficiency—the two clauses do not resolve the tool's actual behavior.

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 an 8-parameter destructive transformation with no output schema and no parameter documentation, the description is far too thin. An agent cannot confidently choose an axis, predict whether originals survive, or understand 'gap'/'snap' from this text alone.

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 8 parameters, so the description must compensate, yet it only loosely hints at 'join' and 'copy'. Axis, at, gap, snap, merge, and artboard are entirely unexplained, and defaults (e.g. which axis is used when omitted) are unstated.

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 gives a concrete verb and resource ('Make a mirrored copy') plus a second mode ('join a half outline with its reflection'), which is clearer than the bare name 'mirror'. It does not distinguish itself from the closely related sibling 'flip', which an agent could easily confuse with mirroring.

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?

Two operating modes are implied (copy vs. join) but the description never states which condition or parameter selects each mode, nor when to prefer this over 'flip', 'transform', or 'boolean_op'. The agent must open the schema and guess.

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