garminconnect-js

add_gear_to_activity

Link a piece of gear to a Garmin Connect activity using gear UUID and activity ID. Raises GarminConnectionError if the gear is not found, retired, or removed.

Instructions

Links a piece of gear to an activity. On 404 re-raises as GarminConnectionError ("gear not found (likely retired/removed)").

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": {
      "gearUUID": "<gearUUID>",
      "activityId": "<activityId>"
    },
    "name": "add_gear_to_activity"
  }
}

Input Schema

Name	Required	Description	Default
`gearUUID`	Yes
`activityId`	Yes	Numeric id

Schema Changelog

Changes observed during successful MCP inspections.

First observedOct 15, 2026

TDQS

B3.1/5.0

Behavior3/5

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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=true. The description adds a useful behavioral detail by mapping a 404 to GarminConnectionError with 'gear not found (likely retired/removed),' but it does not cover idempotency, permissions, side effects, or success behavior.

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

Conciseness5/5

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

Two sentences, front-loaded with the purpose and then a compact error detail. No filler or redundancy; every sentence earns its place.

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?

The tool is a simple mutation with annotations covering its safety profile and no output schema. The description covers the purpose and one error case, but is missing usage context, complete parameter semantics, and side-effect details such as whether linking is additive or idempotent. It is minimally adequate but has clear gaps.

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

Parameters2/5

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

Schema description coverage is only 50%: activityId is described as 'Numeric id' but gearUUID has no schema description. The tool description does not compensate by explaining UUID format, constraints, or how activityId accepts both integer and string. It only adds that a missing gear is likely retired/removed, which is partial semantic value.

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: 'Links a piece of gear to an activity.' This is clear enough to understand the action, but it does not differentiate the tool from siblings such as remove_gear_from_activity or get_activity_gear, so sibling routing is left to inference.

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?

There is no explicit guidance on when to use this tool versus alternatives, nor any prerequisites or exclusions. The function is implied by the purpose statement, but no usage context is provided.

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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