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

Annotations already declare read-only, idempotent, non-destructive, so the safety profile is covered. The description goes beyond that by disclosing the actual computation and the shape of the answer ('compared against the hotend limit, plus the maximum safe speed'), which is the key behavioral detail for interpreting results. It stops short of stating precision, units for the speed limit, or what happens on invalid combinations.

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 tight sentences, front-loaded with the purpose and formula before the input options. The parenthetical list of preset names partially duplicates the enum, and the trailing ellipsis adds little, but overall there is no filler.

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 read-only calculator with no output schema, the description does the necessary work: it explains the computation and names the returned quantities. Missing only minor details such as how conflicting hotend/max-flow inputs resolve and how the speed limit is expressed.

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 coverage is only 20% (just the hotend enum), so the description carries real weight — and it does, by spelling out the formula that maps print_speed_mm_s, line_width_mm, and layer_height_mm to the result. It also resolves the precedence question by presenting 'hotend preset … or an explicit max flow' as alternatives. It does not clarify defaults/ranges for line width and layer height, leaving some ambiguity.

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?

States a specific verb and resource ('check whether a hotend can keep up'), gives the exact formula used, and names the two outputs (flow vs. limit, plus max safe speed). It is unambiguously distinct from the sibling calculators like calculate_filament_usage or calculate_layer_heights.

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 framing ('check whether a hotend can keep up') implies the use case — validating speed against a hotend's limit — but there is no explicit when-to-use, no exclusions, and no pointer to sibling calculators. An agent must infer that this is the right tool for flow/speed validation rather than being told.

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