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

Goes well past the annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=true) by disclosing the exact endpoint, that it mirrors Garmin's own web client payload, the server-side computation of distanceMeter and elevation, the privacy-to-rulePK mapping, and that a GarminError is thrown before any request on empty name or fewer than two points.

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

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

Front-loads the action and its minimum requirements, then layers in endpoint, payload template, defaults, and error behavior. Dense but every sentence adds operational value; no filler.

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

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

For a creation tool with no output schema, the description covers inputs, defaults, server-side effects, and failure conditions. The only gap is what the call returns (a course id/object), which the agent has to infer from the mention of computed distanceMeter and elevation.

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

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

Schema description coverage is 0%, but the description carries the burden by spelling out CourseInput (name, geoPoints, coursePoints?, activityTypeId?=1 running, privacy?="private") and the privacy/rulePK mapping. It says nothing about the per-point shape (latitude/longitude/elevation/distance/timestamp) or coursePoints contents, so it does not fully compensate.

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

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

States a specific verb and resource plus the minimum input needed ('Saves a course from a name and at least two geo points'). This implicitly separates it from create_course_from_gpx, which builds a course from a GPX file, but does not name that sibling outright.

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

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

Usage is implied by the input contract (name + geo points) and the validation rule (at least two geo points), but there is no explicit when-to-use/when-not guidance nor a pointer to create_course_from_gpx, update_course, or import_course_gpx as alternatives.

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