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

Annotations already declare readOnlyHint=true, and the description reinforces this while adding genuinely new behavioral detail: values may be redacted depending on the key's permissions. That redaction behavior is exactly the kind of context annotations don't convey.

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 tight sentences plus an endpoint reference, with the core purpose front-loaded and the read-only/redaction caveats following. Every clause earns its place with no redundancy.

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 two-parameter read tool with no output schema, the description covers the essential behavior, including the permission-driven redaction of returned values. Only the return shape (list format, pagination) is left unaddressed, which is minor here.

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 100%, so both parameters (project_ref, environment enum) are already documented in the schema. The description adds nothing parameter-specific beyond what the structured fields provide, making the baseline 3 correct.

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 ('List') and resource ('environment variables configured for a project environment') with clear scope. No sibling tool touches env vars, and the description makes the domain unmistakable, so the agent can route to it without opening the schema.

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?

Clarifies that this server exposes no env-var writes and that values may be redacted, giving the agent a clear read-only context. There is no competing alternative to name, but it stops just short of explicit when-to-use framing.

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