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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds the event_id provenance rule and the action-dispatch pattern, but says nothing about pagination behavior or the fact that omitting sponsor_id changes the result shape.

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 tight sentences, front-loaded with the resource and scope, followed by the required identifier's provenance. No 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 values need no explanation, and the schema fully enumerates the three action branches. The only gap is that the description never tells the agent the tool is action-polymorphic in behavior (list vs single-sponsor fetch vs categories), leaving that entirely to schema inspection.

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 page, event_id, and the action enum variants are already documented in the schema. The description repeats the event_id constraint but adds no meaning beyond it — 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 names a specific verb and resource ('Read sponsors and sponsor categories') scoped to an event, which cleanly separates it from the create/update/delete sponsor siblings. It falls short of a 5 because it doesn't distinguish itself from other read_* family tools or flag its polymorphic action modes.

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 one concrete prerequisite — event_id must be the UUID returned by search_events — which is genuinely useful routing context. However, it offers no guidance on which action to choose (list vs get vs list_categories) or when to prefer this over nearby read tools.

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