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

Annotations already declare destructiveHint=true, idempotentHint=true, and readOnlyHint=false, so the safety profile is covered. The description adds one genuine behavioral fact beyond the annotations — 'Stops billing immediately' — but omits irreversibility, data/volume fate, and any confirmation or permission requirements for a destructive operation.

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?

Two short sentences with zero filler; the action is stated first and the consequential effect (billing) is front-loaded in the second. Every sentence earns its place.

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 an irreversible deletion the annotations correctly flag destructiveness, and the billing note is a useful addition, but the description leaves material questions unanswered: whether the instance can be recovered, what happens to attached volumes or links, and whether confirmation is required. Adequate but with clear gaps.

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 description coverage is 100%, so the schema already documents id, workspace, and environment including their defaulting behavior. The description adds nothing about parameters, which is acceptable at full coverage and matches the baseline of 3.

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 (terminate) and resource (instance), and the qualifier 'running' narrows the target. It is clearly distinguishable from delete_volume, delete_schedule, and delete_instance_link by the named resource, though it does not explicitly route against any sibling.

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 explicit when-to-use or when-not-to-use guidance. The word 'running' implies only active instances are eligible, but the description never states prerequisites, alternatives, or how this differs from set_instance_auto_stop or other lifecycle tools.

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