## What this fixes
`fan_out_scoped` (`crates/buzz-relay/src/subscription.rs:278-394`)
enforces a deliberate, symmetric scoping invariant — documented in the
code itself:
> Global subscriptions (channel_id = None) do NOT receive channel-scoped
events. Channel-scoped subscriptions do NOT receive global events.
The relay derives a reaction's stored channel from its `#e` target at
ingest — client-supplied `#h` is ignored for channel determination
(`NOSTR.md:50` documents this for *writing*). The consequence for
*reading* is that every reaction is a channel-scoped event, so a live
subscription `{"kinds":[7]}` without `#h` is a global subscription and
**silently receives no reactions at all** — no error, no CLOSED, just
nothing. The working form is `{"kinds":[7],"#h":["<channel-uuid>"]}`,
and it works regardless of how the reaction was signed: explicit `h`
tags on the event are matched directly, and tagless reactions match via
the stored channel fallback (`crates/buzz-core/src/filter.rs:78-91` —
fallback applies only when the event has no `h` tags; explicit tags are
authoritative).
`NOSTR.md` already documents this exact pitfall for group-metadata
events:
> **Note:** Channel-scoped storage means live global subscriptions
(`{kinds:[39000]}`) won't receive these via fan-out.
(`NOSTR.md:124-126`)
…but has no equivalent note for reactions, which is the case a
bot/integration author is far more likely to hit: any client that wants
to observe approvals/reactions live (workflow reaction-triggers make
this a first-class pattern in Buzz) will naturally try a kinds-only REQ
first and conclude reactions are broken. We lost real debugging time to
exactly this while building a headless integration
(https://github.com/OriginTrail/buzz-dkg-integration); the behavior is
by design, only the docs are missing.
## What this PR changes
Docs only (`NOSTR.md`): a subscribe-to-reactions example in "Sending
Messages", plus one note mirroring the existing 39000 note. No code
changes.
## How to verify
- Behavior: with the relay running, open a live REQ `{"kinds":[7]}` (no
`#h`) and react to a channel message from another client → nothing is
delivered; re-subscribe with `{"kinds":[7],"#h":["<channel-uuid>"]}` →
the reaction arrives.
- Claims against code (verified at `485d03a`): scoping invariant
`crates/buzz-relay/src/subscription.rs:386-393`; channel derivation
`derive_reaction_channel()` in
`crates/buzz-relay/src/handlers/ingest.rs`; `#h` fallback
`crates/buzz-core/src/filter.rs:78-91` and its test
`h_tag_fallback_uses_stored_channel_id`.
Duplicate search: no existing issue/PR found for `reactions
subscription`, `fan-out kinds` (searched 2026-07-29). DCO signed-off.
---------
Signed-off-by: Žiga Drev <ziga.drev@gmail.com>
Signed-off-by: npub1jh9wn95s0472h86ahapupaf7m6kx4v9sx2n0atj2hltcfer8k06s5n3pyf <95cae996907d7cab9f5dbf43c0f53edeac6ab0b032a6feae4abfd784e467b3f5@buzz.block.builderlab.xyz>
Co-authored-by: Žiga Drev <ziga.drev@gmail.com>
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
Co-authored-by: npub1jh9wn95s0472h86ahapupaf7m6kx4v9sx2n0atj2hltcfer8k06s5n3pyf <95cae996907d7cab9f5dbf43c0f53edeac6ab0b032a6feae4abfd784e467b3f5@buzz.block.builderlab.xyz>
## Problem
Three small documentation defects, each verified against the code at
06e3d82b:
1. **ARCHITECTURE.md (Event Kinds section)** says `buzz-core` defines
"all 81 kinds". The registry has grown: `ALL_KINDS` in
`crates/buzz-core/src/kind.rs` now has **127** entries (all unique
values). The sentence also says every kind is `pub const KIND_*`, but
registry entries such as `RELAY_ADMIN_ADD_MEMBER` do not use that
prefix.
2. **NOSTR.md Quick Start** numbers its steps 1, 2, 3, 5 — there is no
step 4. PR #797 (2a038515) collapsed the old steps 1-4 (dropping the
separate "Start infrastructure" step) into 1-3, but the final "Connect
any NIP-29 + NIP-42 client" comment kept its old number 5.
3. **NOSTR.md "Further Reading"** is an empty heading — the section's
only content (a link to `crates/buzz-proxy/README.md`) was removed in PR
#1321 (14fba21e) along with the proxy crate itself, leaving a dangling
header as the last line of the file.
## Fix
1. Reworded the ARCHITECTURE.md sentence to defer to
`crates/buzz-core/src/kind.rs` as the source of truth, with the current
count (127) as an explicit "at the time of writing" snapshot, so the
sentence stays truthful as kinds are added. Also removed the incorrect
`KIND_*`-naming claim.
2. Renumbered the final quick-start step 5 → 4.
3. Populated Further Reading with three durable links: the upstream
nostr-protocol/nips repo, this repo's `docs/nips/` extension documents,
and `ARCHITECTURE.md`.
Docs-only; no code changes, no build impact.
## Verification (each claim ~30 seconds)
- Kind count: `python3 -c "import re;
s=open('crates/buzz-core/src/kind.rs').read(); m=re.search(r'ALL_KINDS:
&\[u32\] = &\[(.*?)\];', s, re.S); print(len([e for e in
m.group(1).split(',') if e.strip()]))"` → 127. All 127 values are
distinct. Non-`KIND_*` entry example: `RELAY_ADMIN_ADD_MEMBER` (kind.rs,
in `ALL_KINDS`).
- Missing step: `grep -n '^# [0-9]' NOSTR.md` on main shows `# 1.`, `#
2.`, `# 3.`, `# 5.` in the Quick Start block; `git show 2a038515 --
NOSTR.md` shows the renumbering that orphaned step 5.
- Empty section: `tail -1 NOSTR.md` on main is `## Further Reading` with
nothing after it; `git log -S'buzz-proxy/README' --oneline -- NOSTR.md`
shows the content removal in 14fba21e (#1321).
## Links
- `crates/buzz-core/src/kind.rs` — `ALL_KINDS` registry (source of truth
for the count)
- PR #797 / 2a038515 — introduced the step-numbering gap
- PR #1321 / 14fba21e — emptied the Further Reading section
Signed-off-by: Sean Gearin <sgearin@gmail.com>
Co-authored-by: Sean Gearin <sgearin@gmail.com>
