form_previous_element

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

With no annotations, the description must disclose behavioral traits, but it only says 'move focus' without clarifying side effects like whether focus changes are reversible, if wrapping occurs at the first element, or if any state is modified. The return of 'current element' is ambiguous—does it return a string, object, or just an indication? This lack of detail leaves important behavior undisclosed.

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?

The description is a single concise sentence, which is well-structured and front-loaded. However, it is minimal and does not include any additional useful context, making it more under-specified than appropriately concise.

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?

Given that this is a UI automation tool with a single optional parameter and no output schema, the description is insufficient for an agent to know how to invoke it correctly. It omits prerequisites (e.g., active form), behavior when at the first element, error conditions, and the nature of the returned 'current element'. This is incomplete for a tool that likely relies on state.

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 provides only session_id with a default but no description. Schema coverage is 0%, and the description does not explain session_id at all, nor does it add any context about how the parameter affects the operation. The description fails to compensate for the lack of schema documentation.

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 clearly states the action (move focus) and the resource (previous form element), and mentions the return of the current element. It is specific and easy to understand, but does not explicitly differentiate from sibling tools like form_next_element or current_element beyond the name itself.

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?

No guidance is provided on when to use this tool versus alternatives such as form_next_element or current_element. There is no mention of preconditions, context, or exclusions, leaving the agent to infer usage from the description alone.

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