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

Annotations already declare readOnly, idempotent, and non-destructive, so the safety profile is covered. The description adds the auth requirement (DFX account key) and the shape of the returned data, which is genuine behavioral context beyond the structured fields.

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, with the core purpose and return contents front-loaded and the auth caveat last. No 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?

For a 0-param list tool with no output schema, the description names the returned fields and the account-key requirement, which is enough to call it correctly. It could have clarified what a 'watch' object is or noted pagination, but the essentials are present.

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?

There are zero parameters, so the baseline is 4. The description correctly does not waste space enumerating inputs and instead hints at the account scoping that determines the result set.

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 the resource ('this account's watches') and the key return fields (status, latest checkpoint, reads used, cost), which together clearly convey a list operation. It doesn't name the sibling tools it is distinct from (watch_create, watch_changes, watch_cancel), but the read/list framing is unambiguous.

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 gives a prerequisite ('Needs a DFX account key') but never states when to prefer this over watch_changes, watch_create, or watch_cancel. Usage is implied by the list framing rather than stated explicitly.

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