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

Annotations already declare readOnlyHint=false, idempotentHint=true, destructiveHint=true and openWorldHint=true, but the description adds real value beyond them: the required API key and where to obtain it, the invariant that at least one setting must remain, and the shape of the failure response. It does not restate the safety semantics, so no contradiction.

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-loaded with the action and the mutable settings, then auth and error behavior. Every sentence carries information; the enumerated error fields are slightly dense but operationally useful rather than 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?

With an output schema present, return values need not be explained, and the description still covers auth requirements, the minimum-one-setting invariant, and the error envelope. What is missing is any guidance on partially unspecified parameters, but for a mutation tool this is close to complete.

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 60%, and the schema itself already documents notify_on_drop, notify_on_rise, the threshold fields, api_key and alert_id. The description's 'threshold-free notify_on_drop / notify_on_rise' largely echoes the schema, and it says nothing about the uncovered params (name, webhook_url, notify_email), so it adds only marginal meaning.

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+resource ('Update a price alert') and enumerates the mutable facets (thresholds, notify_on_drop/rise, is_active), so the agent knows this mutates an existing alert rather than creating one. It never names the sibling tools (create_price_alert, delete_price_alert, get_price_alert) to make the boundary explicit, so it falls short of a 5.

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?

It conveys the intended context (switching to threshold-free notifications, changing thresholds, toggling is_active) and one constraint ('at least one setting must remain'), which implies this is for modifying existing alerts. However, there is no explicit when-to-use vs when-not guidance and no routing to get_price_alert for inspection or delete_price_alert for removal.

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