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

With annotations already declaring readOnlyHint=true and destructiveHint=false, the description adds the critical behavioral fact that calls will fail with 501 and that data is not recorded on this gateway. This prevents a wasted invocation and is more than the annotations provide, though it omits details like authentication or exact response shape.

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 sentences with no wasted words. The 501 failure and unavailability are front-loaded, followed immediately by the redirect to the correct endpoint.

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 zero-parameter endpoint that always returns 501, the description fully explains the status and where to find the actual data. With no output schema or complex inputs, nothing further is needed to call this tool correctly.

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, which establishes a baseline of 4. The description appropriately adds no parameter detail because there are no inputs to document.

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 the effective behavior: this tool answers 501 not_available and does not record operator machine utilization/uptime. It distinguishes itself from a normal data-returning get by explicitly declaring unavailability and pointing to the correct endpoint, though it does not name a sibling MCP tool.

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 tells the agent that operator machines are not available here and directs it to GET /api/agent/me for real kernels, devices, and in-flight jobs. The guidance is explicit about the alternative destination but does not spell out a formal when-to-use/when-not-to-use rule.

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