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

Annotations already declare idempotentHint=true and destructiveHint=false, but the description elaborates usefully: re-adding an existing address returns that app instead of erroring, and it discloses a plan-based cap on watcheable apps. It omits auth/permission requirements, but adds real context beyond the structured hints.

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?

Four dense sentences, no filler, with purpose and the primary input front-loaded before the return value, idempotency behavior, and plan constraint. Slightly packed, but every sentence carries information an agent can act on.

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 correctly covers the return value (the app id) and the downstream flow. Plan limits are disclosed; only auth requirements and invalid-URL behavior are unaddressed, which are minor for a single-required-param tool.

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 100%, so url, name, and builder are already fully documented in the schema, including the builder's effect on fix prompts. The description only restates 'give its address' and adds no format or interaction detail, 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?

States a concrete verb and resource ('Start watching a live web app') plus the trigger ('give its address'), so the agent knows this registers a URL for uptime monitoring rather than reading anything. It also names the consumer of the returned id (get_install_instructions), which separates it from read-oriented siblings like list_apps and get_app_health.

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?

Clear context for when to use it (to begin monitoring an app) and an implied follow-up flow via get_install_instructions. It does not state exclusions or when a sibling is preferable, but the triggering condition is unambiguous.

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