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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new context — the data contract version (wr.event.v1) and the testnet environment — which matters for interpreting results. It says nothing about ordering, completeness of the calendar, or how many briefs come back, which are the remaining behavioral questions for this tool.

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 dense sentences with no filler, and the format/environment tag is front-loaded so the agent knows the contract immediately. The parenthetical 'wr.event.v1, testnet' is jargon-heavy but each token carries meaning, and the sibling routing is placed after the resource statement in the right order.

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-param read-only listing with no output schema, the description supplies the essential missing pieces: what the index contains, the record fields, and the handoff to event_brief_get. The only real gap is the absence of any statement about result size, ordering, or pagination, which an agent would want before calling.

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 with 100% schema coverage, so the baseline of 4 applies and there is nothing for the description to compensate for. The field list (id, version, event, sla_met) usefully signals the shape of each index entry, though with no output schema it is the closest thing to return-value documentation.

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?

Identifies a specific resource — the scheduled-event coverage calendar and brief index — and even enumerates the record fields (id, version, event, sla_met). It names the sibling event_brief_get and what that tool returns instead, so the boundary is unambiguous even though the verb 'list' is only implied by the name rather than stated.

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?

Explicitly routes the agent: use this for the index/calendar, use event_brief_get once you already have an id to get the full sealed envelope. That is a concrete alternative-plus-condition. It stops short of stating exclusions (e.g. that this does not return brief contents or support filtering), so it is clear context rather than a full when/when-not rule set.

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