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

Annotations already flag destructive=true and idempotent=true, but the description adds substantial context beyond them: the operation is permanent and non-resumable, the webhook URL is destroyed, later checks report 'cancelled', the MON- id is the sole credential so anyone holding it can cancel, and there is a 30 calls/minute limit. This is exactly the kind of irreversible-effect and auth disclosure the annotations cannot convey.

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?

The irreversible effect and its consequences are front-loaded in the first sentence, followed by alternatives, trigger condition, credential note, and rate limit. Every clause carries information, though the sentence is dense and could be broken up for faster scanning.

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 destructive tool with an output schema (so return values need no explanation), the description covers effects, irreversibility, alternatives, credential sensitivity, and rate limits. Nothing an agent needs to invoke it correctly is 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 coverage is 100% and the pattern already documents the MON- format, so the baseline would be 3. The description adds genuine semantic value by explaining that monitor_id is the only credential and that possession alone authorizes cancellation — a security-relevant property absent from the schema.

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 and resource ('Permanently stop a watchlist monitor') and immediately enumerates the concrete effects: re-screening ends, webhook URL is deleted, status later reports cancelled. It is clearly distinguishable from the sibling create_watchlist_monitor and check_watchlist_monitors without opening either schema.

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?

Explicitly names the two alternatives and the condition selecting each: use create_watchlist_monitor to make a new monitor, use check_watchlist_monitors to read status. It also states the positive trigger ('when monitoring is no longer needed or the webhook endpoint is retired') and the exclusion that the monitor cannot be resumed.

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