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

Annotations already declare readOnly/idempotent/non-destructive, but the description adds genuinely non-derivable behavioral context: an UNMEASURED axis is a declared slot with no run behind it, 'never an error and never a zero,' and 'never a certification.' That prevents an agent from misreading an empty result as failure — real value beyond the annotations.

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 front-loads what the tool is and why it has no inputs, then adds the UNMEASURED caveat. The core sentence is dense (a run-on list of fields), but each clause carries meaning and nothing is padding.

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 an output schema present, return-format details are not needed, and the description adequately explains the no-arg design and the UNMEASURED semantics. What is missing is any orientation toward the sibling axes, so an agent still lacks guidance on when this axis is the right one.

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?

There are zero parameters, so the baseline is 4. The description reinforces this by explaining the tool 'IS the axis, so it takes no argument,' which confirms the empty schema is intentional rather than an omission.

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 measurer-integrity axis of the live GSPC board) and enumerates the exact fields returned (n, accuracy, interval, status, family, kind, artifact URL, dates). It is unambiguous what the tool returns, though it never explicitly contrasts itself against the other axis_* siblings beyond being 'this' 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?

Usage is only implied: 'it takes no argument' tells the agent how to call it, and the fields listed imply when it is relevant, but there is no explicit statement of when to choose this axis over the ~30 sibling axis_* tools or any exclusions.

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