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

Annotations already declare readOnlyHint=false, idempotentHint=true and destructiveHint=false; the description reinforces this with 'Reversible and free' and adds product behavior not in the annotations ('shows up in their app and alerts'). Useful added context about effect and cost.

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 compact sentences, front-loaded with the core action, no redundant restatement of the name/title.

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 one-param mutation with full annotation coverage and no output schema, the description covers the action, effect, reversibility, cost, and input source. Minor gap: no pointer to the inverse remove_from_watchlist.

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% for the single 'company' param, and the description adds meaning beyond the schema by telling the agent the value can be a company id or slug drawn from any search result.

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 (save) and resource (company to the user's Fundz watchlist) with a clear clarifying synonym '(favorites)'. It is trivially distinguishable from the sibling remove_from_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?

Covers the input source ('company id or slug from any search result'), which helps an agent invoke it, but offers no explicit when-to-use/when-not guidance and never names remove_from_watchlist as the inverse. Usage is only implied.

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