image_save

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

The description goes far beyond annotations by disclosing that archives retain layers/tags/metadata, file writes are done by the server's user, `~` expansion, refusal to overwrite unless `overwrite=True`, in-band byte cap due to MCP base64 encoding, and the fallback rationale. Annotations are consistent (readOnlyHint=false, destructiveHint=false) with no contradiction.

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 efficiently structured with an overview, then mode-specific details, then a parameter list. Every sentence adds meaningful information, and the content is front-loaded with the core purpose before diving into technical nuances.

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 tool with two modes, five parameters, and a compound return type, the description is complete. It explains both output shapes (bytes or dict), the byte cap, permissions, overwrite behavior, and the rationale for in-band mode. The existence of an output schema and this description together leave no gaps.

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?

Even though the input schema has no descriptions (0% coverage), the description's 'args' section clearly explains all five parameters: id_or_name, dest_path, named, overwrite, and max_bytes, including defaults and behavior. This fully compensates for the schema's lack of descriptions.

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 a specific verb ('Save') and resource ('image as a tar archive'), and explicitly distinguishes from the sibling tool `container_export` which flattens a container's filesystem. This makes the purpose unambiguous and differentiates it from alternatives.

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 `dest_path` (streaming to disk) vs in-band (fallback when no writable host path), and explicitly contrasts itself with `container_export`. It also notes the purpose (`image_load` restore), giving clear usage context.

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