List roles

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

Annotations already declare read-only, idempotent, non-destructive, but the description adds real behavioral detail: the standard list envelope with has_more=false, item shape {id, name}, and permissions only when include_permissions=true. The pitfalls section discloses that some returned roles are not assignable to memberships and that permission arrays may be absent on some versions, with notes signaling it rather than returning empty.

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?

Front-loads purpose in one sentence, then return shape, then pitfalls, then cross-references — a clean structure. It runs longer than strictly necessary (the cross-reference paragraph and the 403 aside could be trimmed), but nearly every line carries operational value rather than restating the name.

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 an output schema and annotations present, the description still covers the gaps that structured fields can't: configurable role names, non-assignable role types, and version-dependent permission arrays. Nothing an agent needs to call this correctly and interpret the result is missing.

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% and the boolean's own description already covers the cost rationale, so the description is not obligated to explain it. It still adds meaning beyond the schema by stating the concrete output effect ({id, name} plus permissions) and the edge case where the endpoint returns no permission arrays at all.

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 verb and resource ('List the roles this instance defines, with their ids') and immediately frames the tool's role as the id source for create_membership/update_membership role_ids. It distinguishes itself from list_permissions and list_memberships by naming what each answers, so an agent can tell them apart without opening any schema.

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 use context ('id-producing tool for role_ids; role names are never accepted there') and routes to alternatives: list_memberships for roles in use, list_permissions 'when a call just failed with 403'. The when-not-to-use case is effectively covered by that 403 redirection.

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