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

Annotations already indicate destructiveHint=true and readOnlyHint=false, and the description merely repeats that it updates, adding no additional behavioral context such as side effects, scope of changes, or required permissions. It does not contradict annotations, but also provides no extra transparency.

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 description is two sentences that are nearly identical; the first sentence is redundant with the title, and the second repeats it with 'by instanceId'. This wastes the reader's attention without adding substantive information.

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?

Given that there is no output schema and the tool has a nested body parameter, the description is far too sparse. It does not define the update semantics (partial vs full), the effect on the instance, or distinguish it from other update tools. An AI agent would have to guess at the body format and usage.

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 0%, and the description only references instanceId ('by instanceId'), ignoring patchInstanceBody, x-request-id, and x-trace-id. It fails to explain what fields can be patched (e.g., displayName) or the purpose of the headers.

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 restates the title verbatim ('Update specific instance') and only adds 'by instanceId', which is already evident from the schema. It does not clarify which fields are updatable or differentiate it from sibling tools like upgradeInstance or updateImage. This is a tautology.

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?

No usage guidance is provided. The description does not mention when to use this tool versus other instance-related operations (e.g., upgradeInstance, reinstallInstance), nor any prerequisites or exclusions.

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