diff

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

With no annotations provided, the description carries the full burden and discloses the key side effect: it switches by default unless the user asked only to preview or check. It also explains the fallback diff mechanism (nvd, then nix store diff-closures) and when raw diff text is returned instead of structured packages.

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 front-loaded with the core action and output shape, then covers default switching and the fleet alternative. It is dense but every sentence carries operational information; the parenthetical fallback detail is useful rather than redundant.

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?

An output schema exists, so the description need not explain return values, and it does explain side effects and fallback output behavior. However, for a tool with two undocumented parameters at 0% schema coverage, the description leaves a meaningful gap about how mode and flake_uri control the closure being built and diffed.

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%, and the description never mentions the two parameters, mode or flake_uri, nor explains how they affect the build or diff. Because parameter coverage is low, the description should compensate, but here it adds no parameter meaning beyond the schema's bare property names.

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 and resource: build the new closure and diff it against the running system, with structured package changes and closure_size. It also distinguishes the tool from preview/check behavior and fleet deployment via the orchestrator, so an agent can identify its role among 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?

It gives explicit default behavior ('Include the changeset in the reply and switch unless the user asked only to preview or check') and names the alternative for coordinated fleet deployment. This covers when to use it, when to avoid switching, and when to use a different orchestration path.

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