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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, establishing a safe read operation. The description adds value beyond those by disclosing that it returns null when no sprint is active and that terms like focus, cycle, iteration, or week map to the same object. This gives an agent useful behavioral expectations beyond the structured 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?

Three sentences, each earning its place: the trigger context, the null return behavior, and the synonym mapping. The description is front-loaded with the primary usage and contains no fluff or redundant restating of the tool name.

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 read-only tool this is quite complete: it covers when to use it, what it returns in the no-active-sprint case, and terminology variants. One minor gap is that with no output schema, the returned sprint object's shape is not described, but the description's reference to a sprint object is likely sufficient for a simple retrieval 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?

There are zero parameters, so parameter-semantics are fully covered by the schema by definition. The baseline for zero-parameter tools is 4, and the description does not need to add anything further. No parameter documentation is missing.

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 explicitly states what the tool does: get the currently-running sprint, with concrete user-phrase triggers. It distinguishes this from sibling tools like list_sprints and list_sprints by focusing on the active sprint rather than listings. The 'currently-running' scope makes the purpose unambiguous.

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?

Explicit usage guidance is provided: 'Use this when the user asks 'what sprint am I on?' or you need the currently-running sprint.' It also clarifies null behavior when no sprint is active, which helps an agent decide whether the result is valid to use. The synonym clarification adds practical selection guidance without naming alternatives directly.

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