Shared compute now has exactly two model choices: MeshLLM's virtual
`mesh`
model, or a model you name. Buzz picks between them in one place, and
buzz-agent no longer knows meshes exist.
## What changed
- **MeshLLM v0.74.0 → v0.75.1.** v0.75.0 added
`degrade_to_single_model`, so a
`model=mesh` request is answered by one served model when there is no
committee to form, instead of failing. v0.75.1 adds Mesh-LLM#1196, which
skips stale pre-0.75 runtime cache entries rather than aborting startup
on
them — without it, anyone who had run mesh on 0.73/0.74 could not start.
- **Deleted the client-side mesh catalog probe.** buzz-agent used to
poll
`/v1/models` (5s TTL, 30s cooldown, two-observation debounce) to decide
whether `mesh` was safe to send. MeshLLM now decides per request, so the
polling, its hysteresis, and its 503 fallback are gone.
- **One mapping point.** `relay_mesh_wire_model()` turns the stored
value into
a wire name: `auto` becomes `mesh`, a named model passes through. The
spawn
env, the ACP harness, and the readiness probe all use it, so they cannot
disagree — previously `BUZZ_ACP_MODEL` and the probe both said `auto`, a
name
the mesh does not advertise.
- **Removed the `nostr-relay-pool` advisory exception.** #5404 allowed
RUSTSEC-2026-0243 "after mesh-llm migrates to nostr-sdk >= 0.45".
v0.75.1
does, so the retired crate is gone from both lockfiles and the exception
would only mask a future advisory for it.
- **Deleted `scripts/ensure-mesh-native-runtime.sh`** and its six
justfile call
sites. It built llama.cpp from source into the runtime cache; the app
already
downloads the signed release runtime itself, and CI never called it.
## Why it is better
**−639 lines of Rust.** Availability is decided by the node that knows
the
answer, per request, instead of by a client cache that could be stale
for up to
30 seconds. A second worker joining now takes effect on the next request
rather
than after two confirming probes.
## Behaviour change
A 503 on an explicit `mesh` request takes the ordinary transport retry
under
the same model instead of failing over to a second one — there is no
second
model to fail over to now. MoA repairs partial committee results
internally
before it reaches that point.
## Validation
`crates/buzz-relay/examples/mesh_agent_e2e.rs` now sends `mesh` where it
previously sent `auto` or the physical model id, so no leg was covering
what
Buzz actually puts on the wire. 4/4 on gemma-4-E4B, gemma-4-26B-A4B, and
Qwen3-8B — including a real ACP tool call through `mesh` into
buzz-dev-mcp,
asserted by reading the written file back off disk.
Hand-tested in the desktop app on both gemma-4 sizes: picked Auto, agent
logged
`model_id=mesh`, replied in channel.
## Not covered
A committee that forms and then loses a worker returns 502, and that
needs two
workers to reproduce — not testable on one machine.
---------
Signed-off-by: Michael Neale <michael.neale@gmail.com>
Co-authored-by: Michael Neale <michael.neale@gmail.com>
