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

Beyond the annotations, it discloses the required OAuth scope (favorites:write) and confirms the operation mutates buyer/order state. Idempotency and non-destructiveness are already covered by annotations (idempotentHint=true, destructiveHint=false), so the description's added value is the auth requirement and the state-change note.

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?

Three short sentences, front-loaded with the action, followed by auth scope and side effect. No filler or restatement of the name.

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 single-parameter mutation with an output schema and full annotation coverage, the description supplies the key extras: scope, state change, and product eligibility. Only edge-case behavior (e.g., duplicate favorites, failure modes) is left implicit, which is minor given the idempotentHint annotation.

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 coverage is 100% and the schema itself already explains the ID format (internal Vesremont numeric ID, not SKU/article or basket item ID). The description adds a validity constraint on the parameter by requiring the referenced product be a 'current public product,' which meaningfully narrows acceptable values.

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 ('Add a current public product to this buyer's favorites'), which tells an agent exactly what effect to expect. The 'current public' qualifier narrows the operation meaningfully. It does not explicitly name remove_favorite/get_favorites as counterparts, but the action is unmistakable.

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 precondition that the product must be public and current implies when the call is valid (i.e., not for unavailable or private products). However, there is no explicit guidance on when to prefer this over siblings or what to do if the item is already favorited. Usage is implied rather than stated.

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