Assign or change a user-definable value for a device-set part by reference in Fusion Electronics, then verify the update. For fixed-value library parts, select a variant instead.
Set a part's value. Only for device sets with user-definable values; for fixed-value library parts (e.g. passives with one variant per value) use set_part_variant instead.
| Name | Required | Description | Default |
|---|---|---|---|
| ref | Yes | ||
| value | Yes |
Changes observed during successful MCP inspections.
v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=true, idempotentHint=true), so the mutation and repeat-safety semantics are covered by structured data. The description adds a genuine eligibility constraint (device sets vs. fixed-value library parts), but says nothing about failure modes, confirmation output, or side effects on existing variants. Comparable to the calibrated HIGH example, where a scoping constraint against annotation-covered safety earned a 3.
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, zero waste, with the primary action front-loaded and the disambiguation clause following immediately. Every sentence earns its place.
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 low-complexity two-parameter mutation with annotations carrying the safety profile and no output schema, the description covers purpose, eligibility, and the sibling alternative adequately. The remaining gap is parameter meaning, which matters less for self-describing names like 'ref' and 'value'.
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% and neither 'ref' nor 'value' is documented in either the schema or the description. The description only obliquely implies what 'value' means via 'a part's value'; what 'ref' accepts (reference designator? UUID?) is never stated. Low coverage requires the description to compensate, and it does not.
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+resource ('Set a part's value') and explicitly delineates itself from the sibling set_part_variant, which is the tool an agent might otherwise confuse it with. An agent can pick the right tool without opening either schema.
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?
Gives an explicit when-to-use condition ('only for device sets with user-definable values') and an explicit when-not plus the named alternative ('for fixed-value library parts ... use set_part_variant instead'). Nothing is left to inference.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.