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

Annotations already declare the tool as read-only, idempotent, and non-destructive, so no safety disclosure is needed from the description. The description adds the approximate nature of the calculation via 'estimate' but does not disclose assumptions, limitations, or output behavior beyond that.

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 a single, focused sentence with no wasted words. The core action and required inputs are front-loaded, making it easy for an agent to parse quickly.

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?

For a simple two-parameter read-only calculation, the description covers the basic purpose and inputs, but there is no output schema and the description does not specify the output unit or governing relationship. The lack of assumptions or return format leaves some ambiguity for agent use.

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 description coverage is 0%, and the description only restates the parameter roles ('thermal power', 'temperature difference') without adding meaningful detail. The parameter names already carry that meaning, and no units, constraints, formula, or default values are clarified.

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 a specific action: estimate required coolant mass flow from thermal power and temperature difference. This directly distinguishes the tool from siblings like hydronic_pipe_velocity (which concerns velocity) and required_heating_power (which concerns power).

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 implies the tool should be used when you have thermal power and temperature difference and need coolant mass flow, but it does not explicitly state when to choose it over alternatives. No exclusions or sibling comparisons are provided, so usage context is only implied.

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