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

Annotations already signal readOnly/openWorld/idempotent, but the description adds substantial behavioral detail: the three return categories (FIRM YES / FIRM NO / probability estimate), the ~2-day assignment publication timeline, and the fall-through behavior to predict_flight_starlink. This goes beyond what annotations alone convey.

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 sentences, with the usage trigger front-loaded and no filler. Every sentence adds distinct value: when to use, what it returns, and when to use the alternative.

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?

Despite no output schema, the description covers the key return semantics, the timing uncertainty, and the routing to predict_flight_starlink. For a read-only lookup tool with 100% schema coverage and rich annotations, nothing essential is missing for correct invocation.

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%, so the schema already documents all four parameters thoroughly. The description adds little beyond the schema: it reinforces the flight-number/date trigger but does not meaningfully expand param meaning. Baseline 3 is appropriate.

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 description states the exact trigger ('does my flight have Starlink/WiFi?') and the specific resource (tracked-airline flight number and date). It also distinguishes itself from predict_flight_starlink by clarifying that check_flight returns firm yes/no when assignment exists and falls through to an estimate otherwise.

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 says when to use ('with a specific tracked-airline flight number and date'), gives an exclusion ('For dates further out'), and names the alternative (predict_flight_starlink) plus the reason (extra latency). This is strong routing guidance.

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