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

Annotations already declare destructiveHint, idempotentHint, and readOnlyHint=false, so those facts are baseline. The description adds genuine beyond-schema context: authentication is required, the call is FREE and exempt from rate limits, and idempotency is explained as 'safe to call even if course is not in favorites' rather than merely restated.

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?

Four short, front-loaded sentences with the core action stated first; each adds a distinct operational fact. Minor redundancy in restating idempotency that annotations already carry.

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?

A simple one-param mutation with no output schema, and the description covers the essential behavioral facts (auth, cost, idempotency). Only the course_id format is left unspecified, a small gap given the tool's simplicity.

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?

Only one parameter (course_id) with 0% schema description coverage, and the description adds nothing about its expected format or value (e.g., course slug vs numeric ID). With a single undocumented param the description should have clarified it, so this sits at minimum-viable rather than the no-param baseline.

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 (Remove) and resource (a course from favorites/bookmarks), making the inverse relationship to add_to_liked_courses immediately obvious. An agent can distinguish it from sibling tools without opening the schema.

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?

The intent-to-use is clear (when the agent wants to unbookmark a course), and the inverse sibling add_to_liked_courses is implied by the resource. However, the description never explicitly names the alternative or states exclusion conditions, leaving that inference to the agent.

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