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

Annotations already cover safety (readOnlyHint) and open-world reach, so the description correctly spends its words elsewhere: it discloses that the data is crowd-sourced (implying sparse/uneven coverage) and that combining the two identifiers is invalid. It stops short of saying what is returned when no reports exist for a route or which key wins if both are supplied.

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 sentences: what the data is, when to use it, how to call it. Front-loaded and every clause carries information; nothing is redundant with the title.

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?

With no output schema, the description usefully names the return contents, which is the key gap-filler. One hole remains: both parameters are optional (0 required), but the description only says to pass one — it never states the behavior or default when neither is given.

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 both parameters are already documented with examples at the schema level. The description's "not both" mutual-exclusion rule is a genuine addition the schema does not encode, but it adds no format or scoping detail beyond that single constraint.

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?

Specific verb+resource: crowd-sourced in-flight WiFi speed reports, enumerating the returned metrics (download/upload Mbps, latency, per-provider breakdown). This implicitly separates it from siblings like get_wifi_facts or get_flight_wifi, but no sibling is named, so an agent comparing get_flight_wifi vs get_speed_stats must still infer the boundary.

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?

"Use for 'is the WiFi fast enough' questions" gives a concrete triggering intent, and the closing constraint specifies the invocation rule. It does not mention when to prefer a sibling tool instead, so the alternative-selection guidance is implied rather than stated.

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