garmin-connect-api

Add weigh-in

add_weigh_in

Record one body weight in Garmin Connect in kg or lbs with an optional timestamp; use it when no body composition data is needed.

Instructions

Record one body weight in Garmin Connect, in kg or lbs, with no body composition.

For a smart scale reading with fat, water, muscle or bone, use add_body_composition instead. Without a timestamp it is filed now. A timestamp without an offset is taken as local time in the Garmin account's timezone, and one with an offset is moved into that timezone, so it lands on the right day. To correct a reading, delete it with delete_weigh_in (list_weigh_ins gives its sample_pk) rather than adding another.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`unit`	No	kg or lbs.	kg
`weight`	Yes	In the given unit.
`timestamp`	No	ISO 8601. Defaults to now.

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.3.0Oct 20, 2026

TDQS

A4.9/5.0

Behavior5/5

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

Annotations declare readOnlyHint=false, idempotentHint=false, destructiveHint=false, openWorldHint=true. The description adds crucial timestamp interpretation rules (local vs offset) and the fact that adding another doesn't correct but creates a new entry, which is not in annotations.

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?

Four sentences, each front-loaded with purpose, alternatives, timestamp behavior, and correction workflow. No redundancy; every sentence adds unique value.

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?

Complete for a simple mutation tool: covers purpose, alternatives, timestamp semantics, and correction path. Output schema exists, so return values needn't be described.

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% and description adds timezone handling semantics for the timestamp parameter beyond its schema description, clarifying how offsets affect filing. This is valuable but only expands one of three parameters, so not a full 5.

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?

States a specific verb 'Record' and resource 'one body weight' with platform and scope, and distinguishes from sibling add_body_composition by specifying 'no body composition'. This lets an agent pick the right tool without opening schemas.

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 directs to add_body_composition for smart scale readings with fat/water/muscle/bone, and advises using delete_weigh_in for corrections rather than adding another. Provides clear when-to-use and when-not-to-use guidance.

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