Intervals.icu MCP Server

create_custom_item

Create a new custom item, such as a fitness chart, input field, or activity panel, for an athlete on Intervals.icu. Define its type, configuration, and visibility to tailor training data views.

Instructions

Create a new custom item for an athlete on Intervals.icu

Args:
    name: Name of the custom item
    item_type: Type of custom item (e.g. FITNESS_CHART, TRACE_CHART, INPUT_FIELD, ACTIVITY_FIELD, INTERVAL_FIELD, ACTIVITY_STREAM, ACTIVITY_CHART, ACTIVITY_HISTOGRAM, ACTIVITY_HEATMAP, ACTIVITY_MAP, ACTIVITY_PANEL, ZONES)
    description: Description of the custom item (optional)
    content: Configuration content for the custom item as a dict (optional). Important enum values:
        - "type" field for INPUT_FIELD/ACTIVITY_FIELD: must be "numeric", "text", or "select" (NOT "number")
        - "aggregate" field: must be "MIN", "SUM", "MAX", or "AVERAGE" (NOT "AVG")
    visibility: Visibility setting: PRIVATE, FOLLOWERS, or PUBLIC (optional)

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": {
      "name": "<name>",
      "item_type": "<item_type>"
    },
    "name": "create_custom_item"
  }
}

Input Schema

Name	Required	Description	Default
`name`	Yes
`content`	No
`item_type`	Yes
`visibility`	No
`description`	No

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.0Nov 2, 2026

TDQS

B3.1/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It identifies this as a creation operation and gives useful enum constraints for the content field, but it does not describe permissions, side effects, whether the item is immediately visible, or what happens on failure.

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 front-loaded with the core action and then uses an Args list for parameter details. It is appropriately sized, with the enum warnings earning their place, though the formatting is somewhat verbose.

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

Completeness3/5

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

An output schema exists, so return values need not be explained. However, for a mutation tool with no annotations and 0% schema description coverage, the description should do more to cover permissions, side effects, and the full content configuration shape.

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 description coverage is 0%, so the description must compensate, and it does document all five parameters. It lists item_type examples, visibility values, optionality, and important enum constraints for content, though it does not fully explain the content dict structure.

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: 'Create a new custom item for an athlete on Intervals.icu.' It is clear what the tool does, but it does not explicitly distinguish itself from sibling tools such as update_custom_item or get_custom_items.

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 implies creation of a new item but gives no explicit guidance on when to use this tool versus alternatives like update_custom_item or get_custom_items. There are no exclusions or prerequisites mentioned.

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