images_list

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

No annotations are provided, so the description carries the full behavioral burden. It usefully discloses the return contents (name, path, label, timezone plus the default timezone), which the agent would otherwise have to guess since there is no output schema. It says nothing about whether this is read-only, auth requirements, or behavior on an empty registry, leaving a gap for a no-annotation tool.

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?

A single sentence, front-loaded with the action and resource, with the returned fields parenthesized compactly. No wasted words.

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 annotations and no output schema, the description does the essential work by naming the fields returned. For a simple, side-effect-free zero-argument list tool this is close to sufficient; only edge-case behavior (empty registry, ordering) is unaddressed, which is minor here.

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 and the schema is an empty object, so there is no parameter semantics to explain. Per the baseline for zero-parameter tools, a 4 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?

The description gives a specific verb and resource ('List registered disk images') and even enumerates the fields returned (name, path, label, timezone). It is clearly distinguishable from the closest sibling, images_add, but it never explicitly differentiates itself from other list-style tools (jobs_list, etc.). Clear purpose, no active sibling routing.

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?

There is no explicit when-to-use or when-not-to-use statement and no mention of images_add as the alternative. Usage is only implied by the purpose: for a zero-parameter listing tool the invocation context is fairly self-evident, so a 3 rather than a 2.

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