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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint), so the bar is lower. The description adds genuinely useful semantics beyond that: an unmeasured axis is a declared slot with no run, never an error and never a zero, and never a certification. That is real behavioral context about what a returned row means, though nothing about freshness, caching, or rate limits.

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 with the identity of the axis, then the field enumeration, then the unmeasured-state caveat. The closing 'never an error and never a zero. Never a certification.' is terse and purposeful rather than padded.

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 field enumeration is partly redundant, but the description still supplies the source URL for the live board and the crucial semantics of an UNMEASURED row, which a schema alone would not convey. Adequate for a zero-parameter read tool.

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?

Zero parameters, so the baseline applies; the description correctly explains that no argument is taken because the tool is bound to a single fixed axis. Nothing left to document.

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 names the specific resource (the harness-fidelity axis of the live GSPC board) and enumerates what the row contains (n, accuracy, interval, status, family, kind, URL, dates), which distinguishes it from the many sibling axis_* tools by domain rather than by a verb. The operation itself is only implied ('this tool IS the axis'), so the agent must infer that it reads one axis record.

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?

There is no statement of when to use this tool versus get_axis, axis_serving-fidelity, or the other axis siblings — the reader must infer from the name alone. The only procedural guidance is 'it takes no argument', which is about invocation, not selection.

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