# Publication member detail

`POST /v1/member/get` returns one collaborator's membership in a selected
publication. It returns the same member projection as `/member/list`.

## Authentication and access

An authenticated caller must have active membership in the selected
publication. Reading another collaborator requires `member.list`. Reading
the caller's own membership is also allowed with `publication.get`; this
intrinsic read remains bounded by any verified organization profile. Service
administration and public author profiles do not grant publication access.
Archived publications remain readable according to their current permissions.

## Request

Supply exactly one publication selector: `publication_id` (UUID) or
`publication_slug` (string). Supply `member_id` (membership UUID),
`principal_id` (the collaborator's local Blog roster UUID), or both if they
identify the same membership. A member ID alone never selects a publication.

```json
{
  "publication_id": "PUBLICATION_UUID",
  "member_id": "MEMBERSHIP_UUID"
}
```

An alternative lookup uses `publication_slug` and `principal_id`.

## Result

The success envelope has comment `member loaded` and data containing
`publication_id` and `member`. The member includes its IDs, role, status,
timestamps, safe principal name/kind/status, capability mode and selected
capability tag IDs, and the caller's permitted edit/remove/leave actions.
`capability_tag_ids` represents explicitly selected optional grants, not a
computed effective permission set; default-mode grants come from current role
defaults. Last-owner safeguards are reflected in the action flags.

The result contains neither private account/membership metadata nor a public
author biography. An authorized manager may inspect disabled memberships;
disabled callers cannot use their membership to authorize a request.

## Errors

* `400`: missing publication/target, multiple publication selectors, or invalid
  UUID input.
* `401`: missing authentication.
* `403`: missing active publication access or the required read capability.
* `404`: publication unavailable, membership absent from the selected
  publication, or supplied member/principal IDs disagree.

Membership queries are constrained to the selected publication's Management
group before reading the target. A valid membership ID from another
publication returns `404`, even when the caller can access both publications.