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

Annotations declare a write with destructiveHint=true and openWorldHint=true, and the description adds substantial context beyond them: the two-step asynchronous approval flow, that the invitee's agent inherits the workspace default access role until an owner changes it, and a hard security constraint against handling the approval PIN in chat. That is exactly the behavioral detail an agent needs before invoking.

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 scope, then the workflow and the PIN warning. Every sentence carries information, though the semicolon-joined sentence about the invitation link and default access role is slightly dense and could be split.

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 3-parameter mutation tool with full schema coverage, rich annotations and no output schema, the description covers the action, the approval workflow and the security boundary well. It stops short of telling the agent how the staged request is tracked (the sibling workspace_request_status exists) or what a successful call yields, a minor gap.

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 description coverage is 100%, so every parameter including the role enum and the workspace lookup is already documented in the schema. The description's phrase 'by email, as a member, admin or owner' merely restates email+role, adding no syntax, format, or edge-case guidance beyond the structured fields. Baseline 3 applies.

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?

Specific verb + resource + scope: 'Invite someone to a workspace you own by email, as a member, admin or owner.' The ownership precondition and role enumeration make it immediately distinguishable from siblings like add member-adjacent tools (set_member_workspace_role, remove_member, cancel_invitation, assign_access_role).

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?

Explains the operating context clearly: this stages a request, the owner approves it in a browser with their PIN, and the PIN must never be solicited in chat. It does not explicitly contrast with siblings (e.g. use set_member_workspace_role for an existing member, or cancel_invitation to revoke), so no exclusions are stated.

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