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

The annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The one genuinely added fact is "Secret values are masked," which tells the agent that returned values are truncated/redacted and that it cannot retrieve secrets this way — useful, but it is the only behavioral detail given; nothing about ordering, scope of results, or what happens with a nonexistent id.

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?

Two short sentences, front-loaded with the action and followed by the one caveat that matters. Nothing is padded, though the second sentence would read better as an explicit consequence ("secrets are returned masked and cannot be read here").

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 tool whose only parameter is undocumented in both schema and prose, and with no output schema, the description leaves the central unknown — what `id` identifies and therefore which variables are listed — entirely unresolved. The masking note is helpful but does not fill that gap.

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 single required parameter `id` has 0% schema description coverage, and the description says nothing about it — not whether it is a project id, environment id, or deployment id, nor its format. With low coverage the description was expected to compensate, and it does not.

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?

"List environment variables" states a specific verb and resource, which cleanly separates it from mutating siblings like env_set, env_update and env_delete. It stops short of a 5 because it never says whose environment the variables belong to (project, deployment, or account), so scope is ambiguous against a catalog full of project-scoped list tools.

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?

There is no when-to-use or when-not-to-use guidance at all. The closest sibling, env_audit, is left unaddressed, so an agent has no stated basis for choosing between listing and auditing environment variables.

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