subscribe_flight

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

Annotations already declare readOnlyHint=false, non-idempotent, openWorld and non-destructive, so much of the mutation profile is structured data. The description adds useful context the annotations do not: the 'writes enabled' account capability requirement and the downstream effect of is_passenger. It does not say what happens on re-subscribing an already-tracked flight, which matters given idempotentHint=false.

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?

Three short lines, front-loaded with the action and the discovery source, then prerequisites, then parameter semantics. No filler, though the trailing 'Sends the app's is_passenger query string' is low-value implementation detail for an agent.

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 description covers action, prerequisites, and both parameters. The remaining gap is lifecycle behavior: no mention of how tracking is later removed or changed (set_flight_mine, delete_flight) or what a duplicate subscribe yields.

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 0%, so the description carries the burden, and it does explain the non-obvious boolean: true marks it as your flight, false tracks someone else's, plus the note that it is forwarded as a query string. flight_id is only characterized as a 'known flight UUID' from search_flights, which is adequate but slightly thin on format.

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 concrete verb+resource ('Add/track a known flight') and pins the scope to a flight UUID that already exists, explicitly routing discovery to search_flights. This separates it from subscribe_random_flight and upsert_manual_flight without the agent needing the 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 the entry condition (a known UUID, normally obtained via search_flights) and the operational prerequisite ('requires writes enabled'), which is exactly the gating information an agent needs before calling. It stops short of naming alternatives such as subscribe_random_flight or set_flight_mine or explaining when tracking is preferable to those.

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