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>
## Summary
This is **part 1 of 2** split out from #3467 (per Tyler's request),
carrying only the mesh-scoped changes. The agent/ACP response-behavior
changes and the new `send_message` tool stay in #3467 as part 2. All
commits are @michaelneale's work, cherry-picked with authorship
preserved.
- Upgrade embedded Mesh to v0.74.0 (tag-pinned instead of commit rev)
and use canonical Gemma model IDs.
- Keep shared compute serving through member joins, roster changes, app
recovery, and community switching.
- Wait for actual model readiness and avoid resuming incomplete
downloads after quit.
- Leave `BUZZ_AGENT_THINKING_EFFORT` unset by default so each model's
chat template picks its own thinking default (`none` suppressed Gemma
tool-calling entirely; pinning `low` made Qwen3 burn ~4x output budget).
Explicit agent/persona/global values still win.
## Relationship to #3467
Contains the mesh commits from #3467 (`2cd640b23`, `0ad81c341`,
`ad13ed841`) rebased onto current main, with one deliberate exclusion:
the `crates/buzz-agent/src/llm.rs` reasoning→text parser change from
`2cd640b23` is **not** here. That change unconditionally affects every
OpenAI-compat/Responses provider, so it belongs with the reply-behavior
work in part 2, where it can be reviewed as what it is.
Not included (remaining in #3467 / part 2):
- typed `send_message` tool in dev-mcp + `BUZZ_ACP_SEND_MESSAGE_TOOL`
gating
- plain-reply delivery fallback in buzz-acp
(`BUZZ_ACP_DELIVER_PLAIN_REPLIES`)
- the mesh_agent_e2e P5/P6 rewrite (exists to prove the reply path)
- the two `env.insert` preset opt-ins in `relay_mesh.rs` for the flags
above
- the llm.rs parser change
This PR is independently mergeable; part 2's flags are all off by
default so it can land before or after.
## Testing
- `cargo test -p buzz-relay --locked` — 780 passed (one telemetry test
is order-sensitive under parallel default settings; passes in the
pre-push suite and standalone, unrelated to this diff — files untouched
here).
- `just desktop-tauri-test` (default features) — 1877 passed.
- `cargo test --locked --features mesh-llm` in `desktop/src-tauri` —
1961 passed, including the new relay-mesh preset and
coordinator/recovery tests.
- Both `Cargo.lock`s resolve with `--locked` against the v0.74.0 tag.
- Full pre-push hook suite green (rust-tests, desktop-check/test, tauri
checks).
Live validation of the mesh v0.74 upgrade itself is documented on #3467
(two-Mac cross-version test).
---------
Signed-off-by: Michael Neale <michael.neale@gmail.com>
Signed-off-by: Tyler Longwell <tlongwell@block.xyz>
Co-authored-by: Michael Neale <michael.neale@gmail.com>
Co-authored-by: Tyler Longwell <tlongwell@block.xyz>
