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

Annotations already declare destructive=true and idempotent=true, and the description adds concrete consequences beyond them: scaling down stops running processes, scaling web to 0 takes the URL offline, changing size restarts processes, and setting an existing value changes nothing. The instruction to confirm with the user before scaling down is exactly the operational guidance an agent needs for a destructive tool.

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?

Dense but front-loaded: the core action comes first, then per-kind rules, then consequences and caveats. Some redundancy with the schema ("Give count, size, or both; omitting one keeps it" appears in both places) slightly inflates length.

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?

No output schema exists, and the description covers everything needed to invoke correctly: required fields per kind, defaults for omitted params, size semantics, refusal cases, account prerequisite, and destructive side effects.

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%, so the baseline is 3; the description still adds value by explaining that process_type is a Procfile type such as web, that count is bounded by the organization's cap, and that size values differ in stop behavior and trigger a restart. Minor overlap with schema text keeps it below a 5.

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?

Opens with a precise verb+resource: setting process count and/or machine size for one process type of an app or agent. It clearly separates the two target kinds (app vs agent) and is distinguishable from siblings like restart_service, rename_service, and create_service.

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?

Gives explicit per-kind rules (app needs process_type + count; agent count is 0 or 1), states that omitting count/size keeps the current value, and names exclusions: websites are refused and changing an agent's model is not offered here. It also flags the prerequisite of connecting a Valet account.

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