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

No annotations are provided, so the description carries the full burden. It discloses only the scoping constraint ('within its platform set') and says nothing about what happens at the boundaries (e.g. moving the first item left), whether the change is persisted immediately, or permission requirements. For a mutation tool with zero annotation coverage this is thin.

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 verb and scope, with no filler. It is efficient, though its brevity reflects under-specification rather than disciplined trimming.

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 two-parameter mutation tool with no annotations, no output schema, and 0% schema description coverage, the description omits boundary behavior, ordering semantics, and success/failure outcomes. An agent can guess the basic call but not the edge cases.

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 restates the direction values ('left or right') already conveyed by the enum and implies a screenshot identifier, but adds no format, ID source, or ordering semantics for screenshotId. The added value over the schema is marginal.

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), resource (screenshot), and scope (left/right within its platform set), which is enough to distinguish it from siblings like duplicate_screenshot or remove_screenshot. It does not, however, explicitly contrast with reorder_element, the nearest ambiguous alternative, so it stops short of a 5.

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?

There is no statement of when to use this versus reorder_element or update_screenshot, and no prerequisites are named. The phrase 'within its platform set' hints at a precondition (the screenshot must already belong to a set), but the agent must infer it.

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