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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered. The description adds the computation formula and input grouping but nothing about precision, rounding, units, or error behavior beyond what annotations and the output schema supply.

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?

Front-loaded purpose, then formula, then inputs, then return — short and scannable with no padding. The telegraphic fragments ('Returns distance.') are terse but not wasteful.

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?

An output schema exists, so the description needn't explain the return value, and annotations cover the safety profile. Formula plus input enumeration is enough for an agent to call this correctly; only unit/coordinate-system assumptions are left unstated.

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%, so the description carries the burden, and it does name all six parameters and implies the point-1/point-2 pairing (x1,y1,z1 vs x2,y2,z2) that the schema's alphabetical property order obscures. However it adds no unit conventions, coordinate-system assumptions, or type detail beyond the names themselves.

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 ('Compute Euclidean distance between two 3D points') and even gives the formula, which unambiguously separates it from calculate_distance_2d. It stops short of naming that sibling explicitly, so an agent must infer the 2D/3D split from the name alone.

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?

'Use for 3D modeling, physics' gives domain context but no when-to-use rules, no exclusions, and no pointer to the 2D alternative. The trailing 'See list_bundles for related math calculators' is a weak discovery hint rather than routing guidance.

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