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

With no annotations, the description bears full burden. It mentions the formula and a return value but is vague and potentially misleading (claims returns C_coefficient, while likely output is flow rate). No disclosure of assumptions, edge cases, or whether the tool is read-only.

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?

Two concise sentences, each with clear purpose. However, the return mention is awkward and could be more front-loaded. No waste, but could be improved by correcting the return description.

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 the tool has an output schema (not described) and 4 parameters, the description is incomplete. It doesn't explain the output format or provide enough context for correct invocation. The confusing return mention adds to incompleteness.

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 provides 100% coverage with descriptions for all parameters. The description adds no extra semantic meaning beyond the formula and return mention. Baseline 3 is appropriate as schema does the heavy lifting.

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 calculates water flow rate using the Hazen-Williams formula. It mentions the return value (though confusingly as '{C_coefficient}') and references related tools. The verb and resource are specific, and the formula name helps differentiate from other pipe calculators.

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 only suggests seeing list_bundles for related calculators, offering no explicit guidance on when to use this tool versus alternatives like calculate_pipe_diameter or calculate_flow_rate_convert. No when-to-use or when-not-to-use conditions are stated.

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