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

Annotations already declare destructiveHint=true, readOnlyHint=false and idempotentHint=false, so the safety profile needs no restating. The description contributes one genuinely new behavioral fact: the change applies only on next restart. It omits whether deletion is reversible and what scope (which app/deployment) is affected.

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 tight sentence with no filler, and the restart caveat is placed immediately after the core action. Nothing is padded, though there is also nothing beyond the minimum.

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, non-idempotent mutation with zero schema description coverage and no output schema, the description is thin. It does not say what happens to existing deployments using the variable, whether the deletion is recoverable, or what 'id' scopes — all things an agent needs before invoking a delete.

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%, so the description carries the full burden, and it does not explain either parameter. It never clarifies what 'id' identifies (app, deployment, or project) or that 'key' is the variable name, so an agent must guess the meaning of a required identifier.

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 specific verb and resource: 'Delete a user environment variable'. The qualifier 'user' scopes it beyond system vars, and the sibling set (env_set, env_update, env_list) makes the intent unambiguous. It does not explicitly contrast with env_update, which is the only thing keeping it from a 5.

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?

Usage is strongly implied by the verb — an agent will know this removes a variable — but there is no explicit when-to-use versus env_update or env_set (e.g., setting an empty value is not the same as deleting). The restart note hints at when the effect matters but does not guide selection among the env_* family.

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