registry_manifest

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

Annotations already mark this as read-only, but the description adds valuable behavioral details: it may return single-platform or multi-platform manifests depending on the registry, it uses HTTPS directly without a daemon, and username/password overrides ignore config.json. No contradiction with annotations; the description enriches the safety profile with operational 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 efficient and well-organized: a clear purpose statement, then a concise behavior note, alternatives, an 'Args' section with each parameter, and a 'Returns' section. No superfluous text; every sentence contributes to understanding. Front-loading the purpose is exemplary.

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?

For a 4-parameter tool with no output schema, the description is complete. It covers the action, the return structure (dict with name/registry/reference/media_type/digest/manifest), parameter details, and situational context (alternatives). An agent has all necessary information to invoke it 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?

Schema description coverage is 0%, so the description fully compensates. Each parameter (repository, reference, username, password) is explained with examples and default behaviors, including the stripping of tags/digests from repository and the override semantics for credentials. This is far beyond what the schema provides.

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 opens with a specific verb and resource: 'Fetch a repository's manifest without pulling.' It clearly distinguishes the tool from siblings by naming alternatives (`buildx_imagetools_inspect`, `image_registry_data`) and highlighting the direct HTTPS approach vs. daemon/CLI. This makes the tool's purpose unambiguous.

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 states when to use this tool vs. alternatives: 'Talks HTTPS directly - no daemon or CLI needed' and names the specific alternatives with their trade-offs (CLI/credential store vs. daemon). Also provides guidance on parameter usage, noting that `:tag`/`@digest` is stripped from `repository` and must be passed via `reference`. This is comprehensive.

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