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

Annotations already flag destructiveHint=true and readOnlyHint=false. The description adds real behavioral detail beyond the annotations: `false` cuts open connections 'within seconds' and requires a kept top-up (billing/auth requirement) while being free. This is useful context the structured fields do not convey.

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 first sentence is front-loaded and states the core capability, but the text is a dense run-on with 'kept top-up' repeated three times and the get/set explanations folded awkwardly into one paragraph. It is understandable but could be tightened and split into clearer labeled lines.

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 output schema, the description helpfully states what `get` returns (on/off plus account eligibility) and what `set` does in each state, and it discloses the destructive cut-off from the annotations. Only minor gaps remain, such as nothing about how `<name>` is chosen or response error cases.

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% and the description compensates: it explains what `action: get` versus `action: set` do, which the schema leaves undocumented, and reinforces the `enabled` true/false semantics (including the connection-cutting consequence). It adds meaning beyond the schema's terse descriptions.

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?

The description states a concrete verb and resource: enabling/disabling name-based (`<name>.sandbox.internal`) TCP reachability between sandboxes, plus the `get`/`set` duality. It is clear and specific, but it does not explicitly distinguish itself from networking siblings like runtime_networks_upstream_proxy or runtime_networks_wireguard, which an agent might otherwise confuse it with.

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?

It clearly separates the two actions: `get` reports current on/off state and account eligibility, while `set(enabled)` toggles reachability with explicit true/false outcomes. The 'Needs a kept top-up' condition tells the agent a prerequisite. However, it offers no guidance on when to prefer this over the other network tools.

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