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

Beyond the annotations (readOnly=false, idempotent=false) it discloses real side effects: geocoding of the address, rejection if the target route is active, a re-optimization flag being set on optimized routes, and that duplicate calls create two distinct stops. The route-precondition and re-optimization consequences are not derivable from any structured field.

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?

Four compact sentences, write-intent front-loaded, followed by the geocoding fact, the route_id branch, and the duplicate-call caveat. No filler; the endpoint path is the only arguably extraneous element.

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?

Given 22 optional parameters, a 100% documented schema, and no output schema, the description covers the crucial creation semantics and route preconditions. It does not say what the response contains (e.g., the new stop's id), which an agent would need for follow-up calls, but that is a small gap.

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 schema already documents all 22 parameters, including that address is geocoded and that route_id may be omitted. The description mostly restates this; the added value (route must not be active) is behavioral rather than parameter semantics, so the baseline of 3 applies.

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?

Opens with 'WRITE: create a stop', a specific verb+resource that separates it from read siblings like upper_list_stops and from the mutating counterpart upper_update_stop. It is clear what is produced, though it never names the alternative (update_stop) explicitly.

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 concrete conditional guidance: pass route_id to schedule, omit it for an unscheduled stop, and the route must not be active/in progress. It does not contrast with upper_update_stop or upper_create_route, so an agent must infer when to create versus update, but the route_id branch is well specified.

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