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 it well: it discloses the 500-event page cap, the pagination contract (tag → after_tag, remainingEvents), and the important caveat that events can arrive out of order from offline devices. That is real behavioral context an agent cannot infer from structured fields.

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 tight sentences, front-loaded with purpose and event types, then pagination, then the ordering caveat. The event-type list is long but pays for itself by enumerating the return values in the absence of an output schema.

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 compensates by naming the returned fields (tag, remainingEvents) and the event types, plus the ordering caveat. An agent has everything needed to call and paginate 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?

Schema coverage is 100%, so the baseline is 3, but the description adds meaning beyond the schema by explaining the tag's role in the incremental-read loop (returned tag feeds the next call's after_tag). That closes the schema's vague 'tag from a previous call' into an actionable workflow.

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?

States a specific verb and resource ('Read driver-app events for the live routes') and enumerates the exact event types it returns. No sibling tool covers event reading, so the distinction from get_routes/get_dispatch_status is 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?

Clearly prescribes the usage loop: pass the returned tag as after_tag to fetch only newer events, and check remainingEvents for more. It does not name an alternative tool or state exclusions, but no sibling performs this function, so the routing guidance is effectively complete.

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