env

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

The description states 'Read-only, no side effects,' which aligns with the readOnlyHint annotation and adds context that it returns JSON. No contradictions; the description fully discloses behavior beyond annotations.

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 concise with five sentences, each adding unique value: purpose, read-only guarantee, output format, use case, and differentiation. No redundant or unclear language.

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?

Given low complexity (2 optional params, no output schema), the description is thorough. It covers purpose, behavior, output format, usage context, and alternatives, making it complete for agent invocation.

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 schema coverage is 100%, so the baseline is 3. The description adds value by explaining filtering by name pattern and structured JSON output, but the parameter descriptions in schema are already clear. Slight bonus for contextualizing usage.

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 all environment variables or filters by name pattern as structured JSON. It uses specific verbs and distinguishes from sibling tool 'printenv' by noting that 'env' is for patterns, not exact names.

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?

The description explicitly tells when to use this tool (inspect execution context, filter by pattern) and when not to (exact name lookup), directing to 'printenv' as alternative. This provides clear guidance for agent decision-making.

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