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

The 'Read-only' note merely restates readOnlyHint=true, so it adds no new behavioral disclosure. It does indicate the payload shape (built-in vs custom roles with permissions), which is useful context but modest beyond the annotation.

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?

Two sentences, front-loaded with the resource description and then the usage guidance. The parenthetical CLI reference ('twin of ankra org roles') is slightly wasteful for an agent but the rest is tight.

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?

For a zero-parameter, read-only list tool with no output schema, the description covers what the tool enumerates and why it is used. It stops short of describing return structure, but that gap is minor given the simple surface.

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?

Zero parameters, so the schema carries no semantics to underspecify. The description correctly implies the tool takes no input, though it adds no additional parameter meaning because there is none to add.

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 specific resource and scope: the roles members can hold in the organisation, including built-in and custom roles with their granted permissions. An agent can distinguish this from siblings like list_organisation_members at a glance.

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 explicit when-to-use: to explain what a member may do, or which role a request needs. However, it names no alternative tool or exclusion, so the agent must infer that this is the reference lookup rather than a membership listing.

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