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

With no annotations provided, the description carries the full burden of behavioral disclosure. It adds a valuable detail: when two roots exist, the stable phase is chosen by minimum fugacity, not root count. This reveals internal selection logic. It also lists outputs, giving the agent an idea of what to expect. It doesn't discuss side effects, but for a calculation tool this is less critical.

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 two sentences with the main purpose front-loaded. The first sentence is information-dense and efficient. However, the second sentence 'Powered by multicalci.com' is promotional and does not help an agent select or invoke the tool, slightly reducing conciseness. The structure is otherwise clear and scannable.

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?

The description explains the outputs and the key root-selection behavior, which is useful. However, it does not describe the output structure (no output schema exists), nor does it clarify the role of optional parameters like molecular_weight for computing density or molar volume. For a thermodynamic calculation tool with 6 parameters, this is a noticeable gap, but the core functionality is adequately covered.

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 input schema has 100% description coverage for all parameters, so the schema already provides units and meaning. The tool description does not add any further parameter-level context, such as typical ranges or dependencies (e.g., molecular_weight is optional and defaults to 28.96). Thus, it meets the baseline for high schema coverage but adds no extra value.

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 identifies the tool's outputs (Z, molar volume, density, fugacity coefficient) and the method (Peng-Robinson EOS), which distinguishes it from sibling tools that handle valve sizing, pipe flow, etc. However, it lacks an explicit verb like 'calculate' or 'compute', relying on the noun phrase to imply the action.

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 gives no guidance on when to use this tool versus alternatives. It does not mention any alternative tools, limitations, or prerequisites. The only implied usage is from the tool's name and outputs, which is insufficient for an agent deciding between this and other engineering calculation tools.

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