worldparts

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add_control

Automate a component input by reading a measured result and adjusting it with PI or hysteresis control, maintaining setpoints and avoiding rapid cycling.

Instructions

Add a control that reads one result and writes one component input.

pi: solve finds the output holding the setpoint (control_saturated if unreachable); simulate runs it after each step's solve. hysteresis: on below on_below, off above off_above (short_cycling if too frequent). Returns every control.

Input Schema

TableJSON Schema

Name	Required	Description
`name`	Yes	Control name (identifier).
`type`	Yes	Control law.
`actuate`	Yes	Numeric input it writes, e.g. 'pump.speed'.
`measure`	Yes	Numeric result path, e.g. 'pump.outlet.p'.
`settings`	Yes	pi: setpoint (e.g. '4 bar'), gain (output per measured unit, > 0), integral_time ('10 s'), output_min?, output_max? (default: input limits), direction? ('reverse' default: raise the output when the measure is low; 'direct'). hysteresis: on_below, off_above, on_value, off_value, initial? ('on'\|'off'), max_switches_per_hour? (6).
`system_id`	Yes

Output Schema

TableJSON Schema

Name	Required	Description	Default
`controls`	Yes
`system_id`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 24, 2026

TDQS

A3.6/5.0

Behavior4/5

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

The description goes beyond the annotations by explaining execution behavior: pi runs during solve and simulate, 'control_saturated' appears when unreachable, and hysteresis has threshold and short-cycling behavior. This adds meaningful context without contradicting the readOnly/openWorld/destructive hints.

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?

The description is compact and front-loaded with the core purpose, then uses efficient colon-separated type breakdowns. It is dense but not bloated, though the pi/hysteresis details could be slightly better organized.

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?

Given the output schema exists and annotations cover safety, the description covers the main behavioral aspects and return value ('Returns every control'). It lacks explicit side-effect or error information, but for a 6-parameter tool with nested settings, it is reasonably 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 high (83%), but the description adds valuable parameter semantics, especially for the settings object: it explains pi setpoint/gain/integral_time and hysteresis on_below/off_above behavior. This goes beyond the raw schema definitions.

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 states a specific verb and resource: 'Add a control that reads one result and writes one component input.' This clearly distinguishes it from adding components or removing controls, though it does not explicitly name sibling tools for differentiation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

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

The description provides detailed guidance for the two control types (pi and hysteresis) but does not explain when to choose add_control over alternatives like set_values, connect, or add_component. No when-to-use or when-not-to-use conditions are given.

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