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

With no annotations, the description carries the full behavioral burden. It discloses that this is a list operation and names the returned fields, but it does not state permission requirements, whether all images are returned, pagination behavior, or ordering. The addition of return fields is useful context beyond the schema.

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 two tight sentences with no wasted words. The core purpose and return fields are front-loaded, followed immediately by the recommended usage condition.

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 zero-parameter list tool with no output schema, the description gives enough context: what is listed, which fields are returned, and when to call it. No additional detail is strictly required for an agent to use it correctly.

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 has zero parameters, so there is no parameter semantics to document. The description appropriately avoids irrelevant parameter detail, though it does not need to compensate for any missing 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 uses a specific verb-resource pair: 'List the Docker images pushed to the user's CitadelHosts registry.' It also names the returned fields (name, tag, size bytes), making the scope unambiguous and distinguishable from the app, job, backup, and territory list siblings.

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?

It explicitly states the key usage condition: 'Verify pushes here before referencing images in create_custom_app.' That tells the agent when to use the tool, but it does not name alternatives or exclusions for cases where verification is unnecessary.

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