Conciseness

Lean, sectioned routing guidance with no explaining of concepts Claude already knows — e.g. "Require the exact delegated/shared mailbox owner email address or UPN" and "Treat send_email_on_behalf as high impact"; every line earns its place. Not a 2 because there is no padding to tighten.

Actionability

Concrete, executable references throughout — named actions (list_shared_messages, fetch_shared_message, send_email_on_behalf, mark_shared_email_read_state, move_shared_email) and the exact parameter mailbox_user_principal_name; per the instruction-skill scoring note, absence of code is not penalized when guidance is this specific. Not a 2 because the action and parameter names are copy-paste concrete, not pseudocode.

Workflow Clarity

A clear 5-step sequence with a pre-write checkpoint ("say which mailbox is being used before performing the write") and explicit error recovery ("If a write fails because shared/delegated scopes are unavailable, say the shared-mailbox action or scope is the blocker"). Not a 2 because the confirmation checkpoint and feedback loop satisfy the validation requirement for these high-impact sends.

Progressive Disclosure

Under 50 lines with no external references needed (no references/scripts/assets bundle exists) and clean sections (Required Target, Action Routing, Workflow, Safety, Example Requests), matching the under-50-lines allowance for scoring 3 on organization alone.

Specificity

Lists multiple concrete actions — "read another mailbox, send from or on behalf of a shared mailbox, mark shared mail read or unread, move shared mail, or browse folders" — matching the 'lists multiple specific concrete actions' anchor; not a 2 because coverage is comprehensive rather than partial.

Completeness

States what ("Work with delegated or shared Outlook Email mailboxes") and when via an explicit "Use when the user explicitly wants to..." clause; not a 2 because the trigger guidance is explicit, not merely implied.

Trigger Term Quality

Natural phrases a user would say — "read another mailbox", "send from... a shared mailbox", "mark shared mail read or unread", "move shared mail", "browse folders" — give good coverage; not a 2 because common variations are present rather than missing.

Distinctiveness Conflict Risk

A clear niche (delegated/shared mailboxes) with distinct triggers that separate it from the signed-in-user Outlook skill; not a 2 because the shared/delegated framing makes overlap unlikely.