MCP Action Firewall

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

No annotations provided, so description carries full disclosure burden. While it states what data is returned, it omits critical behavioral traits: whether sensitive values are filtered/redacted, the return format (object vs string), and side effects (if any). For a tool exposing environment variables, security transparency is a significant gap.

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?

Single compact sentence of 11 words with zero waste. Information is front-loaded with the core action ('Returns all environment variables') followed by usage context ('helpful for debugging...').

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 zero parameters and no output schema, the description covers basic functionality adequately. However, for a diagnostic tool returning environment variables, the omission of security considerations and return value structure leaves a clear completeness 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?

Zero parameters present; per calibration rules this establishes a baseline of 4. The description provides necessary context that the schema (empty object) cannot convey regarding what the tool operates on.

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?

Description clearly states it 'Returns all environment variables' with specific verb and resource. It distinguishes from siblings (echo, get-sum, etc.) by specifying environment variables as the target resource. Minor gap: 'Print' in title vs 'Returns' in description could be aligned, but meaning is clear.

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 implied usage via 'helpful for debugging MCP server configuration', indicating when the tool is useful. However, lacks explicit when-NOT-to-use guidance, prerequisites, or comparison to sibling diagnostic tools like echo.

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