registry_image_config

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

Beyond the readOnlyHint annotation, the description discloses the multi-hop resolution (manifest -> platform manifest -> config blob), 'without pulling', and that platform is ignored for single-platform images. It doesn't cover error handling or rate limits, but the added context is meaningful.

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?

Front-loaded with a one-sentence summary, followed by a clear purpose line and structured args/returns. Every sentence earns its place with no redundancy or fluff.

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?

Specifies the return dict structure including platform being None for single-platform, and explains the resolution hops. With no output schema, the description provides all necessary contextual information for correct invocation.

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 0%, so the description's 'args' section fully compensates by explaining each parameter with examples, defaults, and override behavior (e.g., username/password overriding env vars). The stripping of :tag/@digest is also clarified.

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?

States 'Fetch and parse an image's config blob from a registry without pulling' — a specific verb, resource, and outcome. This clearly differentiates from siblings like registry_manifest, which 'only points at via config.digest'.

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?

Explicitly frames the tool as answering 'what's inside this image?' and contrasts it with registry_manifest, which is the natural alternative. This provides concrete guidance on when to use this tool instead of registry_manifest.

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