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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds real behavioral context beyond that: default ordering, the fixed 118-element domain, and the important silent-exclusion rule that elements lacking a value for the range or sort property are dropped from the results.

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 sentences, no filler: the first enumerates all filter axes cascade-style, the second carries defaults and the edge case. Front-loaded and appropriately sized for an 11-parameter tool.

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 query tool with 11 all-optional params at full schema coverage, the description covers filter families, default ordering, result-set size, and the null-handling rule. No output schema exists, but a flat element list is implied and nothing needed for correct invocation is missing.

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 100%, so the baseline is 3, but the description adds semantics the schema does not state: min/max and sort interplay with missing values, producing silent omissions. That is a meaningful clarification of parameter behavior rather than restatement.

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 (list elements) plus scope: all 118 elements in atomic-number order when unfiltered, and the filter axes available. It doesn't name the siblings (get_element, search_elements) to draw a boundary, but the tool's identity is unambiguous.

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?

"Without filters it lists all 118 elements in atomic-number order" clearly establishes the default behavior and the filtered path, so an agent knows when this is the right call. It stops short of explicit routing guidance such as when to prefer search_elements, so it's clear context without exclusions.

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