List container registries

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

Annotations already establish the safety profile (readOnlyHint=true, idempotentHint=true, destructiveHint=false), and the description adds value beyond them with 'Passwords are never returned' — a key behavioral guarantee that prevents an agent from expecting usable secrets in the response. No contradiction with annotations; the read-only hint aligns with 'Lists.'

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?

Three short sentences, each earning its place: the action and scope, the purpose context, and the behavioral guarantee. The core action is front-loaded and nothing repeats the title or the schema content.

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?

Given a full output schema, 100% parameter coverage, and safety annotations, the description covers the remaining essentials: what the resource is, that it operates at one level, and that passwords are excluded. The only notable gap is not steering the agent to get_registry for a single credential, but call behavior is otherwise fully specified.

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%, so the baseline of 3 applies even without parameter info in the description. The phrase 'at one level' lightly echoes the scope semantics, but the schema already fully explains the repository/organization/global hierarchy and which IDs each requires, so the description adds little new parameter meaning.

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: 'Lists the container registry credentials at one level.' The 'at one level' qualifier is meaningful and maps to the scope parameter. It is clearly the collection counterpart to get_registry among siblings, though it does not name that alternative explicitly.

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?

Usage is implied rather than stated: 'These are what let a pipeline pull private images' tells the agent these credentials are relevant to pipeline image pulls, suggesting this tool is for inspecting available credentials. However, there is no explicit when-to-use guidance, no mention of get_registry for single credential lookups, and the level-selection logic lives entirely in the schema's scope parameter rather than the description.

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