vm_health_rca

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

Annotations only declare readOnlyHint=true, so the description carries the burden for behavior beyond safety. It helpfully discloses what it checks and that output is cause + action per finding, but it does not state the time window for 'recent stats,' how halted/paused states are classified, or whether it requires guest tools to be present to reach a verdict. Useful but incomplete.

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?

Front-loaded with the tag and purpose, then the flagged conditions, then args in a clean block. Slightly long due to the args section, but no sentence is wasted.

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 read-only RCA tool with no output schema and only two optional params, the description is nearly sufficient: it names what is analyzed, what conditions are flagged, and the one-VM vs. fleet switch. The remaining gap is operational detail (time window, output shape), which the agent would otherwise have to infer.

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 0%, so the description must compensate. It does explain both params: vm_id as the optional single-VM selector and target as the Xen Orchestra config target name with a default when omitted. That is adequate coverage of intent, but it adds no format details (e.g., uuid format, available targets) beyond schema field names.

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?

Specific verb+resource: 'VM health root-cause analysis — cause + action per finding.' It explicitly lists the four failure conditions it flags (halted, paused/suspended, running without guest tools, CPU/memory pressure), which distinguishes it clearly from siblings like vm_stats (raw metrics) and vm_get (config detail).

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 states the scope choice explicitly: 'Analyze one VM (vm_id) or the whole fleet,' and explains that omitting vm_id analyzes everything. It does not name alternative tools (e.g., use vm_stats for raw metrics instead), so it stops short of a 5.

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