What version is this repo at right now?

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

Annotations already declare readOnlyHint=true and idempotentHint=true, lowering the bar. The description adds genuine context beyond them: the tool reads from a 'primary target' rather than from file contents, and the value it returns is canonical. The 'Read-only' tag restates the annotation but does not contradict it.

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 plus a short tag, with the core action front-loaded and the usage guidance immediately after. The only mild waste is 'Read-only,' which duplicates the readOnlyHint annotation, but it is a two-word cost and the overall density is excellent.

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-parameter tool with an output schema and annotations already covering the safety profile, the description covers when to call it, what it reads, and the authority of the result. The only meaningful gap is not explicitly routing the agent away from the nearest sibling rrt_version_overview, though the purpose statement partially handles that.

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?

With zero parameters, the baseline is 4 and there is nothing for the description to document. It still adds semantic value by defining what 'version' means in this tool's scope ('configured version groups'), which helps an agent interpret the empty input schema correctly.

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 uses a specific verb+resource pair: 'Read the current version of every configured version group from its primary target.' The 'authoritative value, not whatever a file happened to say' framing distinguishes it from the similar-sounding sibling rrt_version_overview, so an agent can tell it apart without opening any schemas.

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?

'Use whenever a version number is about to appear in a commit message, changelog heading, docs string, or release note' is an explicit, concrete when-to-use trigger. It also gives an implied when-not ('not whatever a file happened to say'). However, it never names alternative tools explicitly (e.g., rrt_version_overview or rrt_bump), so it falls just short of a full 5.

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