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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered and the description's 'Read-only' is largely redundant. It still adds genuine behavioral context the annotations lack: sources originate from deploy_application with stack:false or the dashboard, and an orphaned source is usually a leftover from a deleted one-off container, which helps the agent interpret results.

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?

Content is front-loaded with the core purpose and the 'source' switch, and the stack/origin caveat earns its place by preventing misinterpretation of empty sources. The final sentence is dense and multi-clause, but every clause carries disambiguating information rather than filler.

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 burden of describing returns and does so: per-state image counts, newest images, and full image history when 'source' is set. Combined with the origin/lifecycle explanation, an agent has enough to call and interpret this correctly, though pagination or result-size behavior is unaddressed.

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 100%, so the baseline is 3, but the description adds cross-parameter semantics the schema does not spell out: 'source' switches the tool into full-image-history mode, and the images/search interplay is framed as mode selection rather than independent filters. This goes modestly beyond the per-parameter schema text.

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 names a specific verb and resource ('List the hub's image sources') and immediately defines what an image source is, including the three concrete origins (Docker Hub target, private registry, Dockerfile repo). It explicitly carves out what this tool is NOT about ('Stacks do NOT use image sources'), which disambiguates it from the stack-related 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 gives clear conditional usage: pass 'source' to inspect a single source with full image history, omit to list all. It also tells the agent when results are not stack-related and why a source might be stale. It stops short of naming a sibling alternative (e.g. manage_image_source) for acting on a source, so it is strong but not fully prescriptive.

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