Guest Metrics

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

Annotations already declare readOnlyHint=true, and the description confirms a read operation. However, it adds no further behavioral context—no mention of what metrics are included, how the RRD data is aggregated, rate limits, or response shape. The description carries little informational value beyond the annotation, so it fails to enrich the agent's understanding of the tool's behavior.

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, compact sentence that immediately states the core function. It is front-loaded with the action and resource, with no redundant words or filler. It earns a perfect score for conciseness.

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?

The tool has no output schema, so the description must provide guidance on what the response contains. It only says 'performance metrics (RRD data)', which is vague—it does not specify which metrics (CPU, memory, disk, etc.) are available, nor how the parameters influence the data granularity. For a metrics tool with 5 parameters and no output schema, this is insufficient for an agent to know what to expect or how to interpret results.

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 80%, with descriptions for cf, node, vmid, and timeframe. The description adds the context that type can be 'vm' or 'lxc', which is already in the enum, and mentions RRD data. It does not explain the meaning of cf or timeframe beyond the schema, so it adds minimal value. Baseline of 3 is appropriate given the high schema coverage.

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 clearly states the tool fetches performance metrics (RRD data) for a VM or LXC container. It uses a specific verb 'Get' and a specific resource 'performance metrics', and distinguishes between VM and LXC types. This is unique among the many guest-related sibling tools, so an agent can identify its purpose without ambiguity.

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 description implies when to use it (when performance metrics are needed) but does not explicitly state alternatives or exclusions. It does not mention, for example, that proxmox_guest_status provides status information or that other tools handle configuration. The context is clear but there is no explicit routing guidance.

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