Replace Node.js environment variables

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

Annotations already mark this as destructive and non-read-only, and the description meaningfully expands on that by detailing the full-replace behavior, deletion of omitted variables, process restart, build-time limitations, and masked values from the list endpoint. This goes well beyond the annotations and gives the agent a strong mental model of the operation's consequences.

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 dense but every sentence earns its place. The most critical fact (full replace) is front-loaded, and subsequent paragraphs cover restart semantics, build-time requirements, and the masked-value pitfall without redundancy or filler.

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, side-effect-heavy mutation with no output schema, the description is remarkably complete. It covers what happens to existing variables, what happens on save, when a build is needed, what to do next, and a common data-source trap. The agent has enough context to invoke this tool safely and 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?

The schema already documents the env_vars parameter well, but the description adds crucial operational semantics: the full desired set must always be sent, missing variables are deleted, an empty array deletes everything, and values from the list endpoint are masked and therefore unusable. It also directs the agent to source real values from the project .env file or user prompt, adding practical guidance beyond the schema.

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: 'Replaces the website's Node.js environment variables with the ones provided.' It immediately clarifies this is a full replace, which distinguishes it from list/read and build-related sibling tools. The naming and content align precisely, so an agent knows exactly what operation this performs.

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 gives explicit behavioral and routing guidance: it explains that a restart is enough for Express/NestJS apps, that build-time frameworks like Next.js standalone require a fresh build, and that the 'Start Node.js build' endpoint should be used afterward. It also warns against copying values from the 'List Node.js environment variables' endpoint, giving clear when-to-use and when-not-to-use context.

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