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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered, and the description adds useful semantics beyond them: the returned fields, the fact that unmeasured slots are published gaps rather than failures, and the caveat 'Never a certification'. That is genuine behavioral context an agent could not infer from the hints alone.

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 and the no-argument fact, then the field list. The trailing two clauses about unmeasured rows and 'never a certification' earn their place, though the single dense sentence is harder to scan than it needs to be.

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 zero-param, read-only, open-world tool with an output schema, the description supplies what the schema does not: the meaning of UNMEASURED rows and the non-certification framing. What is missing is any orientation against the many sibling axes, which matters given how crowded this namespace is.

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 is 4; the description correctly reinforces that no argument is accepted. The enumerated fields (n, accuracy, interval, status, family, kind, URL, dates) are output semantics, which are already covered by the output schema, so they neither help nor hurt here.

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 a specific resource ('the jail axis of the live GSPC board') and asserts that the tool IS that axis, but 'jail axis' is domain jargon and it draws no boundary against the ~30 sibling axis_* tools or against get_axis, which also returns axes. An agent knows it returns a row of the GSPC board but not why to pick this over axis_safety or get_axis.

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 takes no argument" sets invocation expectations, and the explicit rule that an UNMEASURED axis is a first-class answer 'never an error and never a zero' is real consumption guidance. However, there is no when-to-use / when-not-to-use framing and no routing to an alternative sibling.

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