iaqualink-mcp

iaqualink_set_light

Idempotent

Set a pool or spa light's brightness or color/show effect on iAqua systems, requiring confirmation before applying the change.

Instructions

Set a pool/spa light’s brightness (dimmable lights: 0, 25, 50, 75 or 100 %) or color/show effect (color lights — Jandy, Pentair, Hayward; the effect names are listed by iaqualink_get_status with view "full"). iAqua systems only. The current color cannot be read back from iAqualink, so an effect change is confirmed only by the light being on. Asks the user to confirm first: a confirmation prompt where the client supports one; otherwise the first call returns a preview and a confirmToken, and only a repeat call with that token proceeds (see MCP_CONFIRM_MODE).

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "serial": "<serial>",
      "aux": "<aux>"
    },
    "name": "iaqualink_set_light"
  }
}

Input Schema

Name	Required	Description
`aux`	Yes	The light’s aux number, aux_<n> name, or label
`effect`	No	Color lights: an effect name (e.g. "Caribbean Blue") or its number
`serial`	Yes	System serial number, from iaqualink_list_systems
`brightness`	No	Dimmable lights: 0, 25, 50, 75 or 100
`confirmToken`	No	ONLY for the two-step confirmation fallback (a client without MCP elicitation). The confirmToken from this same tool's phase-1 "confirmation-required" response, passed back ONLY after the user has seen that preview and explicitly approved it in chat — never on the first call, never invented, never reused. Call again with the same arguments. Ignored when the client supports elicitation.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.1Nov 11, 2026

TDQS

A4.6/5.0

Behavior4/5

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

Goes well beyond the annotations by disclosing that the current color cannot be read back from iAqualink and that an effect change is confirmed only by the light being on — an important observability limit. It also documents the two-step confirmToken fallback and MCP_CONFIRM_MODE, though it doesn't say what happens if the token is stale or how long it is valid.

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-loads the capability and keeps every sentence load-bearing, but the nested parentheticals and em-dash asides make it dense to scan on first read. Slight restructuring would preserve all content with less nesting.

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

Completeness5/5

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

No output schema exists, yet the description explains the shape of the phase-1 "confirmation-required" preview response and how the follow-up call works, plus the read-back limitation. That covers everything an agent needs to invoke and interpret this tool correctly.

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: which parameter applies to which light type, the discrete brightness set, the source of legal effect names, and the strict usage contract for confirmToken (never on first call, never invented, never reused).

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

Purpose5/5

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

Names a specific verb and resource (set a pool/spa light's brightness or color/show effect) and scopes it to iAqua systems, which separates it from generic siblings like iaqualink_set_aux or iaqualink_set_equipment. It also points to where the valid effect names live.

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

Usage Guidelines5/5

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

Explicitly splits the two modes: dimmable lights take 0/25/50/75/100 %, color lights take an effect name from iaqualink_get_status with view "full". It also states the platform restriction (iAqua only) and describes the mandatory confirmation flow, so an agent knows when and how to call it.

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