Set sandbox lifetime

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

Annotations already flag destructiveHint=true and idempotentHint=true, so the description's real value is the consequence detail: the sandbox stops and loses its files, except for an attached volume. That is genuinely beyond the annotations. It doesn't address edge cases such as whether this works on an already-paused sandbox or how the server resolves competing timeout changes.

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?

Three short sentences: effect first, usage second, constraint last. Every clause carries information — consequence, intent, and range — with no padding.

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 two-parameter mutation with annotations covering idempotency and destructiveness and no output schema, the description supplies the missing pieces: relative timing, file-loss behavior, and units/range. Only minor operational context (permissions, behavior on paused sandboxes, error conditions) is absent.

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 50%: sandboxId is documented but lifetimeMs has only bare numeric bounds. The description compensates well by naming units (ms) and the range 60,000–86,400,000 with the '(a day)' anchor, though it doesn't explain what happens if the new lifetime is shorter than the elapsed time.

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 (change sandbox lifetime) and clarifies the change is measured 'from now', which is a non-obvious semantic. It does not explicitly distinguish itself from siblings like sandbox_pause or sandbox_delete, which also terminate/limit a sandbox, so an agent must infer 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?

'Use it to keep a sandbox the user still needs, or to end one sooner' gives clear positive usage contexts for both directions of adjustment. It stops short of naming the alternatives (pause vs. delete) an agent should consider when the intent is stopping rather than rescheduling.

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