diff

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

Describes the diff process, fallback mechanism (nvd/nix store diff-closures), and what changes are reported. Lacks explicit mention of side effects or permissions, but overall informative.

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?

Single sentence covering core functionality and usage hint. Could be restructured for clarity, but is efficient.

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?

Output schema exists, reducing need for return value details. However, missing parameter guidance and safety info given no annotations.

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?

With 0% schema description coverage, the description provides no explanation for the two parameters (flake_uri, mode). Fields are left entirely undefined.

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 clearly states the tool builds a new closure and diffs it against the running system, showing package additions, removals, and version changes. This distinguishes it from siblings like build, check, or switch.

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 says 'Use before switch' indicating when to invoke. However, it does not discuss alternatives or when not to use the tool.

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