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

Annotations only declare readOnlyHint=true, so the description carries the rest and does so usefully: ordering (newest first), optional site scoping, and the per-run payload fields (checkId/journey/checkName, status, trigger, timing, error/warning). It does not discuss volume ceilings or pagination behavior beyond the limit parameter, so it is short of exhaustive.

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?

One compact sentence front-loads the resource, ordering, and scope, then uses a trailing clause to route to the detail sibling and enumerate the returned fields. There is no filler; every clause adds information.

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 no output schema, the description must convey the return shape, and it does so by enumerating the fields each run carries. Combined with the ordering and annotation-covered safety profile, an agent has what it needs; only pagination/volume behavior is left unstated.

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?

Schema description coverage is 100%, so both parameters (limit with its 1-100/default-25 range, siteId) are already fully documented in the schema. The description only restates site scoping ('optionally for one site') and never mentions limit, so baseline 3 is appropriate.

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 states a specific resource (runs) with its ordering (newest first) and optional scope (one site), so the agent knows exactly what comes back. It also differentiates from the closest sibling by noting 'get_run has the detail,' making the list-vs-detail split 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?

It gives clear context for when to use this tool (browsing recent runs, optionally narrowed to a site) and explicitly names the alternative for detail (get_run). There is no explicit 'do not use for X' exclusion beyond that routing, so it stops short of the top score.

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