uni-t-uts-mcp

set_emi_limit_line

Idempotent

Create or edit an EMI limit line by setting its type, trace, margin, and up to 12 frequency/amplitude points; copy points from another line or build them from a trace.

Instructions

Create or edit an EMI limit line. EMI module must be active (select_instrument_module). Give any of: displayed, type (upper/lower), trace, margin_db and margin_enabled, points (replaces the whole point list; 1 to 12 points in ascending frequency order, equal frequencies make a vertical step, each with frequency_hz, amplitude_dbm and optional connected), copy_from (copy another line's points into this one) or build_from_trace (build points from a trace's current data). copy_from/build_from_trace are sent first, then the other settings. The line is re-read afterwards; anything the instrument did not take is reported in 'warnings'.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "set_emi_limit_line"
  }
}

Input Schema

Name	Required	Description
`line`	No	Limit line number, 1 to 6 (EMI mode has only 3 traces to test against, see 'trace')
`type`	No	upper: the trace must stay below the line; lower: above
`trace`	No	Trace number to test against the line (EMI has only 3 traces; the manual documents 1-6)
`points`	No	Replace the whole point list: 1 to 12 points in ascending frequency order (equal frequencies make a vertical step)
`copy_from`	No	Copy another limit line's points into this one (sent before points/other settings)
`displayed`	No	Show the line on the display
`margin_db`	No	Margin in dB, -40 to 40
`instrument`	No	Which instrument to use (a name from list_instruments). Default: the `default` instrument, or the only one configured
`margin_enabled`	No	Margin on/off
`build_from_trace`	No	Build this line's points from a trace's current data (sent before points/other settings)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.1.0Nov 13, 2026

TDQS

A4.2/5.0

Behavior5/5

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

Beyond the annotations (readOnlyHint=false, idempotentHint=true), it discloses ordering behavior (copy_from/build_from_trace are sent first, then the other settings), replacement semantics for points, the 1-12 ascending-frequency constraint with equal frequencies creating a vertical step, and the read-back/warnings reporting behavior. That last point is valuable context on a mutation tool with no output schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with purpose and precondition, then a compact enumeration of the accepted fields and the ordering rule. The nested parenthetical for points is dense but each clause carries information. Slightly crowded as one paragraph but no sentence is wasted.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 10-parameter, zero-required mutation tool with no output schema, it covers the prerequisite, the field combinations, ordering, and the warnings-based return behavior well. It leaves the line selection range (1-6, default 1) and the instrument parameter unmentioned, relying on the schema, which keeps it just below fully complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds real meaning: operation precedence between copy_from/build_from_trace and the other settings, and that points replaces the entire list rather than appending. The line (1-6) and instrument parameters are left entirely to the schema, which is acceptable given full coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb+resource: "Create or edit an EMI limit line." It names the prerequisite tool (select_instrument_module) and the fields it accepts, so an agent can tell it apart from the generic set_limit_line and from get_emi_limit_line/delete_emi_limit_line. It never explicitly routes to those siblings, which keeps it 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.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It states a hard precondition (the EMI module must be active, via select_instrument_module) and explains the payload model: "Give any of" plus copy_from/build_from_trace as alternatives to supplying points. It does not say when to prefer set_limit_line over this tool, nor when editing versus creating is appropriate, so it stops short of explicit when-not guidance.

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

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