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

Annotations already establish that this is a safe, non-destructive, non-open-world read. The description adds domain semantics the annotations cannot: the eight capabilities model, that a mailbox omitted from a role defaults to read & write across all folders and calendars, and that ownership is required. That is meaningful behavioral context beyond the structured fields.

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-loaded with the returned content and efficiently packed with domain detail; the default-mailbox rule earns its place. The opening sentence is a dense colon-list, but nothing is wasted and there is no filler.

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 must convey the return shape, and it does so in prose (capabilities per role, followers, mailbox narrowing), which is adequate for a simple read tool. The safety profile is covered by annotations. Only the absence of sibling routing keeps it from a 5.

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?

One parameter with 100% schema description coverage, so the schema already explains that 'workspace' takes a name or id and is only needed when owning multiple workspaces. The description adds nothing about the parameter, which matches the baseline 3 for a fully documented single-param schema.

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 states a specific resource (access roles of a workspace the caller owns) and even enumerates what each returned role contains: capabilities, followers, and mailbox narrowing. That is well beyond a tautology. It does not, however, explicitly contrast itself with siblings such as list_workspace_members or create_access_role, so it falls short of a 5.

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?

"Owners only" is an explicit precondition, which is genuine usage guidance. But there is no statement of when to reach for this versus list_workspaces (to resolve a workspace) or the access-role mutation tools, and no exclusions. Usage is implied rather than routed.

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