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

Annotations already declare openWorldHint=true, idempotentHint=true, and readOnlyHint=false with destructiveHint=false, so the write/safety profile is partly covered. The description adds real behavioral context beyond that: alerts route to the account's channels, fire on a new low, 'any' fires on every move, and target_price_usd replaces alert_rule. It does not clarify persistence or how to undo the tracking, which is what stop_tracking_flight/update_flight_tracking presumably cover.

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 'Use to...' framing followed by trip-type branching, so the most important routing rule comes first. It is dense and slightly run-on, but nearly every clause carries a distinct routing or alert-behavior fact.

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 tracking-creation tool with 5 params, one required, full schema coverage, and an output schema present, the description covers the confirmation precondition, the per-trip-type ID requirement, alert channel routing, and the alert_rule/target_price_usd interaction. Nothing an agent needs to call it 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%, so the baseline is 3, and the description earns above that by explaining that itinerary_id's meaning shifts by trip type (outbound vs complete pairing) and that target_price_usd supersedes alert_rule rather than combining with it. It adds usable semantics the flat schema cannot express.

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 ('start price alerts on an itinerary from a search') and immediately differentiates from siblings like update_flight_tracking, list_tracked_flights, and stop_tracking_flight by describing it as the creation action. An agent can identify the tool's role without opening any 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?

Explicitly routes the agent by trip type: one-way uses any itinerary_id from search_flights, round trip uses either an outbound or a complete itinerary_id, multi-city needs a complete one. It names the sibling source tools (search_flights, search_return_flights) and the precondition that the traveler has confirmed, which is a strong when-to-use signal.

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