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

Annotations already cover the read-only, non-destructive safety profile, and the description adds meaningful context beyond them: the subscription prerequisite producing HTTP 403, the endpoint path, and the semantic link between returned ids and the customProperties map on stops. It omits pagination/return-shape details, but with zero parameters that is a minor gap.

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, front-loaded with the resource and its returned fields, then the key linkage, then the operational caveat. Every sentence carries distinct information; the endpoint path is the only mildly redundant 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?

With no output schema, the description compensates by naming the returned fields (ids and names) and explaining the id semantics, plus the auth/subscription failure mode. It stops short of noting ordering or size limits for a list call, but is otherwise sufficient for a zero-parameter read.

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?

The tool takes no parameters, so the baseline of 4 applies. The description correctly implies an unparameterized, team-wide listing and adds no parameter information, which is appropriate given there is nothing to document.

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 identifies a specific resource (the team's custom stop property definitions, with ids and names) and the underlying endpoint GET /team/customStopProperties. It goes beyond the title by explaining that the returned ids serve as keys in customProperties on stops. No sibling covers custom properties, so explicit differentiation is unnecessary.

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?

Usage is implied by the resource name rather than stated. The one genuine guideline is the subscription dependency ('Needs a subscription that includes custom properties (HTTP 403 otherwise)'), which tells the agent a failure condition but not when to prefer this tool over alternatives — and there are no direct alternatives among the siblings.

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