# atproto glossary

Concept budget: 6. Everything else is boxed out (see bottom).
Rule: a concept only earns a place here after we've needed it.
Write entries in our own words; delete entries that stop being true.

## The 6

**repo** — a user's signed document store. Like a personal git repo hosted by
their PDS. Every record linji writes lives in somebody's repo: chat messages
in the author's, community definitions in the community account's.

**record** — one JSON document in a repo. Validated against a lexicon (which
is just a JSON schema). The same `at.linji.*` shape works in both publicity
modes.

**collection** — a folder of same-typed records, named by NSID:
`at.linji.post`, `at.linji.membership`. A repo is just a set of collections.

**AT-URI** — `at://did/collection/rkey`. The universal path. Records reference
each other with these; post → channel → community is just AT-URI fields on
records. Space URIs extend the shape: `at://{authorityDid}/space/{type}/{skey}`.

**DID + handle** — identity. DID is the permanent id (`did:plc:…`), handle
(`@you.linji.at`) is the readable alias that resolves to it. One DID, one
repo, present in many communities.

**space** — a permissioned data space (proposal 0016): where member-only
records live. Two server roles: an authority (policy + writer registry, no
content) and each writer's repo host (their signed records). Access is by
space credential, exchanged from a short-lived delegation token. During the
invite-only era, one zds plays both roles.

## Frozen defaults (reversible, don't re-litigate)

- AI role: bot participant deferred (2026-08-02, S013); the published
  CLI is the bot surface. Companion waits.
- Chat publicity: member-only (spaces) in phase 001; public records in
  phase 003. Same schema in both modes.
- Invitee PDS: hosted zds. Load-bearing — space writers need a space-capable
  PDS.
- Iteration sandbox: local zds fork (`./zds/`), 2–3 test accounts. No
  federation, no relay.

## The box (do not open until forced)

Relay, firehose, jetstream, AppView-as-concept, MST, CAR files, PLC
directory, DID methods, labelers, federation. Network plumbing. Matters when
we interoperate with apps we didn't write — phase 002 earliest. Until then
"the network" is a single opaque dependency behind zat's XRPC client.

## Reference notes

- roomy.space's published lexicons are event-stream schemas, not records;
  their record-based redesign is gated on the same permissioned-data proposal
  as our spaces mode. Watch, don't copy.
- zds permissioned spaces (`com.atproto.space.*`, simplespace member lists)
  are the member-only substrate. Experimental — all access behind one thin
  core module, and every zds upgrade must pass the scenario suite before the
  class touches it.
- Lexicon conventions: [ref/lexicon-style-guide.dj](ref/lexicon-style-guide.dj)
  (Bluesky's guide, CC-BY).