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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds non-obvious behavioral semantics beyond the annotations: unmeasured axes are published as declared slots with visible gaps, are never errors and never coerced to zero, and the output is 'never a certification' — meaningful interpretive context for an agent reading 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?

It is a single dense block that front-loads the resource and URL, and every clause roughly earns its place, but 'this tool IS the axis' is conceptually cute and the enumeration of return fields (n, accuracy, interval, family, kind, URL, dates) is partly redundant with the existing output schema. Readability suffers from the run-on structure.

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?

With annotations covering safety, an output schema covering return shape, and zero params, the description's remaining burden is interpretive semantics — which it supplies via the unmeasured-as-first-class-answer and 'never a certification' caveats. Only the failure to position itself against sibling axes keeps it from a 5.

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 tool takes zero parameters, so the baseline is 4. The description also clarifies why ('takes no argument'), which correctly sets the expectation that no filtering or identification argument is needed.

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 identifies a specific resource (the cross-reality axis of the live GSPC board) and enumerates the row fields it surfaces, but never states a clear verb like 'returns' or 'reads' — 'this tool IS the axis' is a conceptual framing rather than an action. With ~30 sibling axis_* tools plus get_axis, it offers no differentiation about what makes 'cross-reality' distinct from the others beyond the name.

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?

It explains how to interpret an unmeasured result (first-class answer, never an error or zero), which is genuinely useful usage context, but it gives no guidance on when to call this versus get_axis, board_totals, or any other axis tool. There are no exclusions or alternatives named despite a dense sibling set.

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