ui_set_value

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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the bar is lower. The description adds valuable context: the action-tier/allowlist requirement, the method (UI Automation, no key simulation), the limitation with modern apps (e.g., Win11 Notepad), and the recommendation to confirm with the user. This goes beyond annotations without contradicting them.

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 three sentences, front-loads the core purpose, and each sentence contributes essential information: what it does, requirements, caveats, and user confirmation. No wasted words, and the structure is clear and scannable.

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 mutation tool with 5 parameters, no output schema, and annotations present, the description covers the core purpose, requirements, limitations, and a usage precheck. It doesn't describe error behavior or return values, but given the tool's simplicity and the annotations, this is reasonably complete. A brief note on success/failure output would make it fully complete.

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 100%, so the baseline is 3. The description adds minimal extra meaning beyond the schema: it clarifies that the value is set via UI Automation and mentions field exposure issues, but doesn't elaborate on individual parameters. The schema already documents all five parameters adequately.

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 tool's function: 'Set text in an editable field via UI Automation.' It uses a specific verb ('Set') and resource ('editable field'), and distinguishes from siblings by noting it does not use key simulation and referencing ui_find as a precheck. This makes the purpose unambiguous and distinct from related tools.

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?

The description provides clear usage context: it requires action tier + allowlist, instructs to check can_set_value in ui_find, warns that modern apps may not expose fields, and advises confirming with the user first. While it doesn't explicitly name alternatives for non-text actions, it gives strong when-to-use guidance and prerequisites.

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