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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered by structured data. The description's only additional disclosure is the set of returned fields, which is genuinely useful given there is no output schema, but it says nothing about behavior when the ID doesn't exist or about permissions.

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 sentences, front-loaded with the returned data and followed by the use case, with no filler. Only minor waste in the framing phrase 'Useful when Claude needs to' instead of a direct imperative.

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 single-parameter read tool with no output schema, the description covers the key gap by enumerating what is returned, and the annotations handle the safety profile. The remaining gap is error/not-found behavior and how to source the incident ID, which is minor for this complexity level.

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% for the single 'id' parameter, and the description adds no format, range, or acquisition guidance (e.g. where to obtain the incident ID). With one fully documented parameter, the baseline of 3 applies.

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 sentence names a specific verb and resource ('Returns incident timeline, outage duration, recovery time, failure reason, affected monitor, and timestamps') and enumerates the payload, so an agent knows exactly what data it gets back. It never explicitly contrasts itself with list-style siblings like read_incidents, but the singular 'a specific downtime event' makes the scope difference inferable.

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?

The second sentence supplies a concrete when-to-use trigger: root-cause investigation of an outage or reading historical logs for a specific downtime event. It lacks any when-not condition or named alternative (e.g. list_then_get via read_incidents), so routing guidance is clear but not exhaustive.

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