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

Annotations already establish the write/idempotent/non-destructive profile, and the description adds genuine context on top: invitees join as Members only after verifying their email, admins manage roles and removal, and the caveat 'Queued does not mean delivered' flags asynchronous delivery. It stops short of stating required permissions or rate limits, but adds real value beyond the annotations.

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 core action and outcome, then supporting constraints; five sentences with little filler. The 'No workspace creation or document move is needed' sentence is slightly indirect but earns its place by scoping the operation.

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 mutation with no output schema and sparse parameter documentation, the description covers membership outcome, the verification step, and delivery caveat, but omits return/result shape, error behavior, and the purpose of the idempotencyKey — an important gap given the required parameter.

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 low (25% — only confirm is documented), so the description must compensate. It contributes the 20-email cap and the conditional need for a shared-library ID, but only 'confirm' is explained in the schema and the description's 'library ID' wording does not clearly map to the schema's 'workspace_id', leaving emails and idempotencyKey semantics unexplained.

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 — inviting people to view/manage the briefs already in the account — plus an outcome (reader activity, leads). It gestures at its scope distinct from a workspace invite ('No workspace creation or document move is needed'), but never names or contrasts the close sibling invite_workspace_members, so sibling differentiation is only implied.

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 rather than stated: the scope note and 'An explicit library ID is only needed for another shared library' hint at when an ID is required, but there is no explicit when-to-use / when-not-to-use guidance and no routing between this and invite_workspace_members.

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