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

With no annotations, the description carries the full burden and does so well: it discloses the one-step granularity, the same-kind restriction, and the full back-to-front paint order (divs, phones, image layers, front divs, texts). It omits edge behavior at the extremes and whether the action is undoable.

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-loaded with the core action before the constraint detail. The paint-order clause is dense and slightly awkward to parse, but nothing here is padding and the size suits the operation.

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 4-parameter mutation tool with no annotations and no output schema, the description covers operation semantics but leaves parameter roles and failure/return behavior unaddressed. Adequate but with clear gaps.

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 'kind' refers to layer kinds and 'direction' is a single forward/backward step, but it never mentions elementId or screenshotId, leaving half the parameters explained only by their enum values or names.

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 specific verb (move) and resource (a layer), plus the exact scope: 'one step forward or backward among layers of the same kind.' This clearly distinguishes the operation from add/update/remove siblings, though it never names an alternative tool to route between.

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?

Usage is implied rather than stated — an agent infers this is for z-order adjustment. The constraint 'cannot move a layer across kinds' is a useful guardrail, but there is no explicit when-to-use framing or comparison to a sibling like move_screenshot.

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