Save one-time secret to a .env file

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

Annotations only declare destructiveHint=true, and the description adds real context beyond that: the file is written with mode 600, the secret is deliberately never displayed, and a warning fires if the file isn't git-ignored. It stops short of saying what happens to an existing KEY entry or whether the file is overwritten or appended.

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?

One dense sentence with the action front-loaded and the two behavioral caveats (mode 600, git-ignore warning) packed into a parenthetical/clause. Efficient, though stacking the warnings inline makes it slightly dense.

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 destructive write tool with no output schema, the description covers the safety-relevant basics (permissions, secret never shown, git-ignore check) but omits overwrite semantics, passphrase handling, and any indication of what is returned. Adequate but with clear 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?

Schema coverage is only 50%, so the description needs to compensate. It clarifies 'KEY=value' for key and that the target is a .env file for path, but says nothing about the passphrase parameter (undocumented in the schema too) or what link looks like, leaving one of four parameters with no explanation anywhere.

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?

States a concrete verb and resource: opens an ncrypted link and writes its value to a local .env file. The word 'local' implicitly distinguishes it from the sibling ncrypted_to_vercel_env, but that sibling is never named explicitly.

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 implies the use case (materializing a one-time secret into a local env file) and mentions a git-ignore warning, but gives no explicit when-to-use vs. when-not guidance and never routes to alternatives like ncrypted_to_vercel_env or ncrypted_read.

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