investigate_vm

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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the description focuses on behaviors they can't express: it returns one correlated bundle rather than the list envelope, all reads are batched, it is a point-in-time snapshot with no trending, and unknown VM names return a teaching error. Only gap is that it doesn't hint at cost/latency or size of the merged timeline.

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 question it answers and the replacement claim, then return shape, then invocation triggers, then boundary. Every sentence carries distinct information, though the list of covered data sources is dense and could be trimmed.

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?

With no output schema, the description carries the return-value burden and does so thoroughly: VM state, host, cluster, datastores, snapshots, alarms, live performance, and a newest-first merged event timeline. It also instructs how to present the result ('explain it in operational language; do not dump it raw'), which is unusual and useful.

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 100% and every parameter is already documented there, including the default 24-hour window and the source for vm_name. The description adds only marginal param context ('merged event timeline' implying the hours window drives it), so the 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?

States a specific verb (investigate/drill-down) and resource (this VM) with explicit scope: 'one correlated drill-down'. It directly distinguishes itself from the composite siblings it replaces (get_vm_info, list_vm_snapshots, get_alarms, get_vm_performance, get_events) and from investigate_host/investigate_datastore by naming the VM as the object.

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?

Explicit routing: use it instead of stitching five specific sibling calls, reach for it after get_cluster_health_summary flags a problem VM, or on a 'what's going on with <vm>?' question. It also draws a clear boundary for when-not: acting on findings (power, migrate, delete snapshot) belongs to vmware-aiops.

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