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

Annotations already carry readOnlyHint/idempotentHint, so restating 'Read-only' earns nothing. What the description adds beyond annotations is real: result ordering (newest first), the exact return-field relationship to listSweepRuns, and the required auth scope ('Needs testing:read'), which the agent cannot learn from structured fields. It does not cover volume or truncation behavior, keeping it below a 5.

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?

Four short, front-loaded sentences with the scope stated first and the routing hint second. Minor waste: 'Read-only' duplicates readOnlyHint=true and 'Takes no parameters' is visible in the empty schema, though both are cheap confirmations rather than filler.

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 return structure need not be re-explained; the description still usefully points to the sibling's field set plus sweepId. Between ordering, auth scope, and the alternative tool, an agent has everything needed to call this correctly.

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 confirms 'Takes no parameters,' which removes any doubt about supplying a workspace or sweep identifier implicitly. No further param meaning is possible.

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?

Names a specific verb+resource ('List the sweep runs') plus the distinguishing scope: across every sweep, workspace-wide, newest first. It also differentiates from the sibling listSweepRuns by stating the exact field delta ('same fields as listSweepRuns plus sweepId'), so an agent can tell them apart without opening either schema.

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 when-to-use is given ('the user asks for recent sweep results without naming a sweep') along with the alternative path ('Name a sweep with getSweep'). The negative condition — no sweep named — is the precise discriminator against the per-sweep sibling, leaving nothing to inference.

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