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

The annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered. The description still adds real value with the "Free" cost signal, the bounded 'last 20 alerts' output shape, and the fact that a secret is required — but says nothing about expiry or error behavior.

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?

One compact sentence with the cost note front-loaded and the credential provenance trailing. Every clause carries information, though "Free." as a standalone fragment is slightly cryptic out of context.

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 no output schema, the description usefully enumerates the return contents and the alert cap, and it identifies the auth inputs. For a two-parameter read tool this is close to sufficient; only failure modes for an expired or unknown watch_id are missing.

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 0% for both required parameters, so the description must carry meaning; it does the important part by stating both values come from watch_field's return, which resolves provenance for an otherwise opaque secret. It gives no format or validation detail.

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 the resource (a field watch) and enumerates exactly what is returned: status, current value, and the last 20 alerts. It is distinguishable from watch_field (which creates the watch) and stop_watch, though it never explicitly states the retrieval verb.

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?

"with the watch_id and secret that watch_field returned" tells the agent this is the follow-up call to watch_field and where the credentials come from. It does not mention when to prefer stop_watch or what to do if the watch no longer exists.

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