registry_image_config

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

Annotations declare readOnlyHint=true and destructiveHint=false, which already establish the safety profile. The description adds significant behavioral context: it explains the three-hop resolution process, the platform selection logic, and the failure mode when no config descriptor exists. It doesn't mention authentication prerequisites, but the username/password parameters are self-explanatory and the overall behavior is well disclosed.

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 somewhat lengthy but well-structured: it front-loads the main purpose, then expands into resolution details, failure cases, and parameter explanations. Every sentence contributes essential information, though the argument list could be streamlined without losing clarity. The use of paragraphs and a separate Returns section improves readability.

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 the tool's complexity (multi-hop resolution, platform selection, failure modes) and the absence of an output schema, the description covers everything needed for correct invocation: it explains the resolution path, the failure condition with an alternative, all parameters, and the exact structure of the return value. No critical information is missing.

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 fully compensates by explaining each parameter in detail: repository strips :tag/@digest, reference is the tag or digest, platform selects from multi-platform images (with default), and username/password override environment variables. This is comprehensive and leaves no parameter ambiguous.

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 states precisely the action (fetch and parse an image's config blob from a registry) and the resource (config blob), and answers the 'what's inside?' question with a list of contents. It explicitly distinguishes itself from registry_manifest by noting that registry_manifest only points to config.digest, making the purpose unmistakable even among many 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?

The description clearly explains when to use this tool: to obtain configuration details without pulling, and how it resolves multi-platform images. It also provides a direct alternative by stating that when the reference is a manifest list rather than an image, registry_manifest reads those, effectively giving a when-not-to-use condition and a named replacement.

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