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

With no annotations, the description carries the full burden and delivers: it discloses the Free watch-only vs Pro act distinction, that Pro POSTs one webhook alert per sandbox, and that it never holds provider keys or kills anything itself. This is exactly the behavioral context an agent needs before invoking a mutating-by-proxy 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?

The core action and cadence are front-loaded, and the dense prose is justified by a genuinely complex tool. It is information-rich rather than padded, though the second half packs several distinct behaviors into long clauses.

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, so the description must explain returns — and it does, describing idle detection, dollar costs, and ready-to-run kill calls, plus the Pro/Free behavioral split and the key-security caveat. Nothing an agent needs to call this 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 high (83%), so the schema already documents the parameters in depth, and per the rubric the baseline is 3. The description only loosely echoes parameters ('your threshold', 'hourly rates you pass') without adding syntax or semantics beyond what the schema states.

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: send running sandbox sessions and receive back idle/over-lifetime sessions, cost figures, and kill calls. The purpose is unmistakable, though it never names a sibling (idle_report, set_idle_rules, weekly_report) to sharpen the boundary.

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 tells the agent when to call it (on a heartbeat, e.g. every 5 minutes) and encodes the Pro-vs-Free decision logic. It stops short of naming an alternative tool or an explicit when-not-to-use condition, so it sits below the top tier.

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