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

Annotations already indicate readOnlyHint=false and destructiveHint=false, and the description adds useful behavioral context: the watchlist is persistent and the note is optional. There is no contradiction, though duplicate handling or confirmation responses are not disclosed.

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?

The description is a single, front-loaded sentence with no filler. It identifies the action, the resource, the persistence characteristic, and the optional note in minimal words.

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 simple two-parameter tool with full schema coverage and annotations, the description is sufficient for an agent to invoke it correctly. It does not cover duplicate additions or idempotency, but that is not critical for an add-to-watchlist operation.

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 100%, with both 'reference' and 'note' already documented in the input schema. The description does not add new parameter-level meaning beyond the watchlist context, so the baseline of 3 applies.

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?

The description states a specific verb ('Add'), a specific resource ('CanadaBuys or Alberta APC opportunity'), and a clear target ('persistent watchlist') with an optional note. This cleanly distinguishes the tool from sibling unwatch_opportunity and list_watchlist.

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 description gives helpful context by restricting the tool to CanadaBuys or Alberta APC opportunities and mentioning the watchlist is persistent, but it does not explicitly say when to use this tool instead of alternatives or when not to use it. Usage is implied rather than directly guided.

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