desktop_set_valueSets the value of a Windows UI element by native handle to automate form fields and controls; requires desktop permission in the active mission step.
Set the value of a Windows UI element by handle. Requires desktop_permission in active mission step.
| Name | Required | Description | Default |
|---|---|---|---|
| value | Yes | Value to set on the element | |
| handle | Yes | Native window handle |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false and destructiveHint=true, so the mutation/safety profile is covered by structured data. The description contributes the permission-gating requirement (desktop_permission in an active mission step), which is additive context, but it says nothing about what existing value gets overwritten, failure modes, or whether the write is immediate.
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 short sentences, zero filler, with the action front-loaded and the gating prerequisite immediately after. Nothing could be removed without losing information.
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 output schema, the description covers purpose, target platform, addressing mechanism, and the permission prerequisite. The remaining gaps (value format expectations, error behavior on invalid handles) are minor given full schema coverage and annotations that already signal destructiveness.
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% with only two required parameters, both documented inline ('Value to set on the element', 'Native window handle'). The description adds no format, encoding, or validity guidance beyond what the schema already states, so the baseline 3 applies.
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?
States a specific verb and resource ('Set the value of a Windows UI element by handle') with a scoping qualifier ('by handle', 'Windows UI element') that separates it from generic input tools. It never names or contrasts a sibling such as desktop_type or desktop_multi_edit, so the differentiation is inferable rather than explicit.
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 supplies a real usage precondition — 'Requires desktop_permission in active mission step' — which tells the agent when the call will succeed. It gives no guidance on when to prefer this over desktop_type, desktop_multi_edit, or desktop_ahk when multiple element-manipulation paths exist.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.