system_env_vars

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

With no annotations supplied, the description carries the full behavioral burden. It usefully discloses that secret-looking values are masked, but says nothing about whether this reads the server process environment or something else, whether output is capped, or that the operation is non-destructive — all left to inference.

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 two behaviors that matter. Nothing is padded or restated from the title.

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?

An output schema exists, so return format need not be explained, and the masking note covers the main surprise an agent would hit. The remaining gap is provenance — whose environment variables are read — which is relevant for a low-risk but ambiguous tool.

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 0%, so the description must compensate, and it does: 'optionally by prefix' tells the agent the single parameter acts as a prefix filter and can be omitted. It does not give examples or say whether matching is case-sensitive, keeping it from a 5.

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 gives a specific verb and resource ('List environment variables') plus two scoping details (prefix filtering, secret masking), which separates it from siblings like system_info or files_read_file. It does not explicitly name an alternative tool, so it falls short of 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?

'Optionally by prefix' implies how to narrow results but never states when an agent should call this versus system_info or system_run_command for environment inspection. Usage is inferable rather than explicit.

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