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

Goes well beyond the annotations (readOnly=false, destructive=true, openWorld=false): create momentarily pauses a running sandbox and wakes it, the volume restriction, the non-retryable fork_unavailable state, delete freeing storage while derived sandboxes keep running, and update leaving captured bytes and billing unchanged. This is the kind of side-effect disclosure a mutation tool needs.

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?

Front-loads the resource definition, then structures the rest per action with parenthesized signatures, which scans well for a five-action tool. It is dense but nearly every clause carries information (constraints, side effects, pagination). Slightly verbose in the retention explanation but nothing wasted.

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 12-parameter, no-output-schema, destructive multi-action tool, the description covers every action, the key constraint, pagination, update semantics and deletion consequences, and even sketches get's return fields. Minor gaps remain, such as the meaning of the state enum values (capturing/ready/failed/deleting), but it is close to complete.

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 58%, and the description compensates by mapping parameters to actions and adding semantics the schema omits: "omitted fields stay unchanged. Null clears the name" for update, and "Pass nextCursor back as cursor" for list pagination. mode, limit, ifLabels and retentionDays are largely already covered by the schema, so it does not fully carry the parameter burden, but it adds real value.

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 definition ("Kept copies of a paused sandbox's files, memory and processes, to start copies from") and then enumerates each action with its arguments. It distinguishes itself from siblings by naming images as the alternative for preinstalling dependencies. An agent can tell exactly what this tool does and each sub-action's scope.

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 concrete when/when-not guidance: volumes cannot be snapshotted and images are the route for preinstalled dependencies; fork_unavailable means snapshots are disabled and must not be retried. It also clarifies that delete leaves sandboxes started from the snapshot running. It lacks a broad routing statement against the many other runtime_* siblings, but the key exclusions and alternatives are present.

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