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

With no annotations provided, the description carries the full burden and does notably well: it declares 'Read-only; sends nothing,' which establishes it is a safe, side-effect-free read, and flags the free API key requirement. It stops short of disclosing rate limits, whether the report is computed fresh or cached, or what a free-tier response looks like.

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?

One dense, front-loaded sentence naming the return contents, followed by two short behavioral clauses. Zero filler, and the most decision-relevant information (what you get, 7-day window) comes first.

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 parameters, no annotations, and no output schema, the description does the work of all three: it describes the return payload field by field, states the safety profile, the auth requirement, and the tier behavior. Nothing essential to calling or interpreting this report 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline is 4. The description's enumeration of returned fields is a bonus that compensates for the absent output schema.

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 (summary) and resource (last 7 days of sandbox idle data) and enumerates the exact content returned: sandboxes watched, idle count, dollar cost, kill calls. The 7-day window implicitly distinguishes it from idle_report, but no sibling is named, so the differentiation is left to inference.

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?

There is no statement of when to call this versus idle_report or usage_and_upgrade, and no exclusions. It notes 'Needs a free API key,' which is a prerequisite rather than usage guidance, and the tier note hints at Pro gating but never tells the agent when this report is the right choice.

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