registry_manifest

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

Beyond the readOnlyHint annotation, it discloses that the response may be a single-platform manifest or multi-platform list depending on the registry's tag, and explains that `repository` strips `:tag`/`@digest`, which is a non-obvious behavior. Also details credential overriding without config.json support. This is substantial added context.

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 dense but every sentence is informative: core action, response variability, transport mechanism, alternatives, parameter doc, and return structure. It is front-loaded with the essential purpose and well-structured.

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?

No output schema exists, yet the description explicitly defines the return dict keys ('name', 'registry', 'reference', 'media_type', 'digest', 'manifest'). The combination of parameter details, alternatives, and response shape makes it self-sufficient for an agent to invoke 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 input schema has zero descriptions, but the description provides full parameter semantics: `repository` with example and tag-stripping note, `reference` with default, `username`/`password` with override behavior. This completely compensates for the schema gap.

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?

Clearly states the primary function: 'Fetch a repository's manifest without pulling.' It goes further to explain the possible response types (single-platform vs multi-platform list) and explicitly names alternative tools, making its purpose unambiguous and distinct from 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?

Directly addresses when to use this tool by presenting alternatives: `buildx_imagetools_inspect` (uses docker CLI and credential store) and `image_registry_data` (asks the daemon). This gives the agent a clear decision framework. Also notes 'Talks HTTPS directly — no daemon or CLI needed' to justify its suitability.

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