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

With no annotations, the description carries the full burden. It explicitly states 'Read-only' (non-mutating) and lists the data returned. It does not cover error scenarios or authentication details beyond the schema, but for a simple get operation this is sufficient.

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 a single sentence, front-loads the resource and scope, and lists return fields with zero redundancy. Every word 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 a simple get-by-id tool with no output schema, the description lists the return fields and states read-only behavior, which is the essential information. It could mention not-found behavior or validity of instanceId, but these are minor gaps given the simplicity.

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 100% (both parameters have descriptions). The tool description adds little beyond the schema: it confirms the instanceId is the machine identifier but does not elaborate on the computeApiKey beyond what the schema already says. Baseline 3 is appropriate.

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 uses a specific verb ('get') and resource ('Cloud machine by id'), and enumerates the exact fields returned (status, IP, price per hour, expiry, AI endpoint). This clearly distinguishes it from sibling list tools like cloud_list_instances and other get-by-id tools for different resources.

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?

The phrase 'One Cloud machine by id' implies usage for a single known instance, which contrasts with list tools. However, it does not explicitly mention alternatives or exclusions (e.g., 'use cloud_list_instances to list all machines'). The context is clear but lacks explicit routing.

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