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

The annotations already cover the safety profile (readOnly, idempotent, non-destructive), but the description adds substantial operational context: a route counts as ONE quota slot regardless of nights, legs are excluded from alert listings, there is no live availability check, and status_as_of is when the scan LOOKED. That is exactly the kind of behavior an agent cannot infer from annotations or schema.

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?

Front-loaded with the definition and the sibling exclusion, and the quota and status explanations each earn their place. It is somewhat long with emphatic phrasing ('certainly before', capitalized LOOKED), but no sentence is pure 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 structure needn't be described, and the description still explains the status vocabulary (rebooked, open_at_last_scan, unverified) and points to status_meaning in the result. Combined with quota semantics and the no-live-check caveat, nothing needed to call or interpret this correctly is missing.

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% with two optional booleans whose descriptions already explain active_only and include_expired. The description only indirectly touches these (mentioning paused and deleted alerts in the status paragraph), adding little syntax or semantics beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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 — the user's multi-night ROUTE alerts (itineraries) — and defines what a route is (a parent plus one leg per night, each night a different site). It explicitly distinguishes itself from the close sibling list_my_alerts, which 'CANNOT show these', so an agent can pick correctly without opening either schema.

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?

Gives explicit when-to-call guidance ('call this too before telling the user what they are watching, before counting their quota, and certainly before suggesting they delete something') and names the alternative (list_my_alerts) plus why it fails. Both the trigger conditions and the routing are spelled out.

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