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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety story is covered. The description adds genuinely useful behavior content it alone can supply — the shape of the response (settings, status, last error, price/stock, diff) — since no output schema exists. It does not say how ambiguous watch matches are handled, which is the remaining gap.

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?

Two tight sentences, front-loaded with the resource and its contents, then the usage trigger. Nothing is redundant and the 'in one call' clause earns its place by signaling efficiency versus composing other tools.

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 read with full schema coverage and clear annotations, the description covers what matters: scope, payload contents, and use case. Only the failure/ambiguity behavior for a non-unique watch match is left implicit by the schema.

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 entry already explains uuid / partial title / partial URL matching including the single-match constraint. The description's use of 'watch' implicitly maps the parameter to a monitor, but adds no syntax or matching detail beyond the schema, so baseline 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 names a specific resource ('one monitor') and enumerates exactly what comes back: settings, status, last error, price/stock, and the latest change as a diff. That distinguishes it from list_watches and from the get_changes/get_diff pair without naming them, though naming a sibling explicitly would have pushed this to 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?

'Answers "what changed on X?" in one call' gives a clear usage trigger and implies that this replaces chaining get_changes + get_diff for a single monitor. There are no explicit when-not conditions or named alternatives, so it stops short of full routing guidance.

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