Discover All VMs

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

Annotations already mark this as read-only, idempotent, and non-destructive, so the description only needs to add behavioral context. It does so by specifying the scanned directories, the optional extra_dir parameter, and the return structure. This adds meaningful detail beyond annotations without contradicting them.

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 well-structured with clear Args and Returns sections, and it avoids unnecessary detail. The first two sentences are slightly redundant ('Discover all' vs 'Scans'), but overall the text is concise and front-loaded.

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 read-only discovery tool with one optional parameter, the description adequately covers the default search locations, the return format, and the optional directory. It does not specify behavior for inaccessible paths or non-standard installations, but given the annotations and simple schema, this is sufficient.

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 schema covers the single optional parameter extra_dir with a description, and the description's Args section repeats that same meaning. No additional parameter semantics, such as default behavior or edge cases, are provided, so it meets the baseline for 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 discovers all VMware Fusion VMs by scanning for .vmx files. It distinguishes from siblings like fusion_list_running through the 'all' scope, but does not explicitly name the alternative or contrast with it.

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 explains what the tool does but offers no guidance on when to choose it over alternatives such as fusion_list_running. There is no mention of exclusions, prerequisites, or situational use cases.

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