printenv

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

Annotations already declare readOnlyHint: true, so the description's statement 'Read-only, no side effects' adds explicit confirmation and additional clarity. It also discloses the return format (JSON). While annotations cover the main behavioral aspect, the description reinforces it without contradiction.

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 three sentences long, front-loaded with the primary action. Every sentence adds value without redundancy. It efficiently covers purpose, usage guidance, and behavioral notes.

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?

With two optional parameters, no output schema, and strong annotations, the description fully explains the tool's behavior. It covers single and all-variable retrieval, read-only nature, JSON return format, and contrasts with sibling 'env'. No gaps remain.

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?

Input schema has 100% description coverage for both parameters (raw and names), so the schema already explains them. The description adds one extra detail about raw mode outputting 'KEY=VALUE lines' but does not significantly enhance meaning beyond the schema.

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 clearly states the tool returns environment variable values, either specific (by name) or all. It uses the verb 'Return' and specifies the resource ('value of a specific environment variable'). It also distinguishes from sibling 'env' by noting direct lookup vs. pattern-based filtering.

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?

Provides explicit when-to-use: 'Use for direct lookup of known variable names.' Also provides when-not-to-use: 'Not for listing all variables with filtering — use 'env' for pattern-based filtering.' Mentions sibling 'env' as an alternative.

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