Put the sign-in variables in .env

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

With only `openWorldHint: false` provided, the description carries the behavioral burden and does so well: it discloses replacement of existing variables, preservation of other entries, .gitignore modification, return of names only, and secret-handling constraints. It also warns not to read the file back to the user and states the auth requirement for reading the secret.

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 and front-loaded, with each sentence contributing operational context. It is slightly paragraph-heavy and packs several constraints into long clauses, but there is no wasted content.

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 mutation tool with no output schema and minimal annotations, the description is complete: it covers side effects, return shape, prerequisites, auth needs, and secret-handling behavior. An agent can infer whether and how to call it without opening the schema.

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 100%, so the schema already documents both `file` and `directory` parameters. The description reinforces that the file lives in the project directory but adds little parameter-specific syntax or format beyond what the schema provides, so the baseline of 3 is appropriate.

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: writing four named auth variables into a .env file and returning only their names. It also distinguishes this from set_env by warning not to copy the variables there, making the tool's scope clear against 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 prerequisites and routing: sign-in must exist first via `auth_create`, and an account token from `login` is required. It also says not to copy the variables into `set_env`, which directly distinguishes this tool from a sibling alternative.

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