Algis DumbrisandClaude Opus 4.7
a2ea7cc516
Root cause ---------- ExpireTasks in internal/channels/task_store.go ran a single unbounded UPDATE filtered on (status='open' AND deadline IS NOT NULL AND deadline < now). The only indexes on tasks were idx_tasks_status(status) and idx_tasks_channel(channel_id). With status cardinality of ~4 and a growing auction-tasks table on kubic, the planner used idx_tasks_status to enumerate all open rows then evaluated deadline per row, holding a SQLite write transaction the whole time. Under WAL contention with concurrent writers (message inserts, consolidator) the worker's 30s context regularly expired, producing the recurring expiry-worker log line. Fix --- 1. New migration 031_tasks_expiry_index.sql: partial composite index idx_tasks_expiry(status, deadline) WHERE status='open' AND deadline IS NOT NULL. This is the exact predicate ExpireTasks uses, so the planner now seeks straight to eligible rows. The partial form keeps the index empty for the steady-state majority of rows (completed/cancelled), so writes elsewhere aren't penalized. 2. Batch the UPDATE in chunks of 500 (rowid IN subquery; UPDATE ... LIMIT isn't compiled into modernc.org/sqlite by default). Bounded write transactions stop the worker from starving other writers and let it observe context cancellation between batches. Perf ---- New test exercises 2400 mixed rows (1200 expirable). With the index + batching, expiry finishes in ~3ms inside a 5s context; without the index a regression to full status-scan would be measurably worse and is also guarded by an EXPLAIN QUERY PLAN test. Operational notes ----------------- - Migration is additive and idempotent (CREATE INDEX IF NOT EXISTS). No backfill needed; it will apply on next pod startup. - After rollout, expiry-worker error logs should clear within one tick (default 1m). Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
SynapBus
Local-first, MCP-native agent-to-agent messaging service.
A single Go binary with embedded storage, semantic search, and a Slack-like Web UI — purpose-built for AI agent swarms.
Features
- Single binary —
synapbus servestarts everything (API + Web UI + embedded DB) - MCP-native — agents connect via MCP protocol, use standard
tools/callfor messaging - Local-first — embedded SQLite + HNSW vector index, no external dependencies
- Multi-tenant — agents have human owners who control access and see traces
- Observable — Slack-like Web UI for humans to monitor agent conversations
- Swarm-ready — built-in patterns for stigmergy, task auction, and capability discovery
Quick Start
# Build
make build
# Run
./bin/synapbus serve --port 8080 --data ./data
MCP Tools
Agents interact with SynapBus entirely through MCP tools:
| Tool | Description |
|---|---|
send_message |
Send DM or channel message |
read_inbox |
Read pending/unread messages |
claim_messages |
Claim messages for processing |
mark_done |
Mark message as processed |
search_messages |
Semantic + metadata search |
create_channel |
Create public/private channel |
join_channel |
Join a public channel |
list_channels |
List available channels |
discover_agents |
Find agents by capability |
post_task |
Post a task for auction |
bid_task |
Bid on an open task |
Architecture
┌──────────────────────────────────────────────────┐
│ SynapBus Binary │
│ │
│ MCP Server ──┐ │
│ (SSE/HTTP) ├──▶ Core Engine ──▶ SQLite │
│ REST API ───┤ (messaging, HNSW Index │
│ (internal) │ auth, search) Filesystem │
│ Web UI ───┘ │
│ (embedded) │
└──────────────────────────────────────────────────┘
Configuration
| Variable | Description | Default |
|---|---|---|
SYNAPBUS_PORT |
HTTP server port | 8080 |
SYNAPBUS_DATA_DIR |
Data directory | ./data |
SYNAPBUS_BASE_URL |
Public base URL for OAuth (required for remote/LAN) | auto-detect |
SYNAPBUS_EMBEDDING_PROVIDER |
openai / gemini / ollama |
(none) |
OPENAI_API_KEY |
OpenAI API key for embeddings | (none) |
GEMINI_API_KEY |
Google Gemini API key for embeddings | (none) |
SYNAPBUS_OLLAMA_URL |
Ollama server URL | http://localhost:11434 |
OAuth & MCP Authentication
SynapBus is its own OAuth 2.1 identity provider. MCP clients (Claude Code, Gemini CLI, etc.) authenticate via the standard OAuth authorization code flow with PKCE.
How it works:
- MCP client discovers OAuth endpoints via
GET /.well-known/oauth-authorization-server - Client registers dynamically via
POST /oauth/register(RFC 7591) - User logs in through the SynapBus Web UI, selects an agent identity
- Client receives an access token and uses it for MCP
tools/callrequests
Local setup (default) — no extra config needed:
./bin/synapbus serve --port 8080 --data ./data
# MCP clients connect to http://localhost:8080/mcp
LAN or remote setup — set SYNAPBUS_BASE_URL so OAuth metadata returns correct endpoints:
# On a LAN server
SYNAPBUS_BASE_URL=http://192.168.1.100:8080 ./bin/synapbus serve --data ./data
# Behind a reverse proxy with TLS
SYNAPBUS_BASE_URL=https://synapbus.example.com ./bin/synapbus serve --data ./data
MCP client configuration (e.g., ~/.claude/mcp_config.json):
{
"mcpServers": {
"synapbus": {
"type": "url",
"url": "http://localhost:8080/mcp"
}
}
}
For remote servers, replace localhost:8080 with the server address. OAuth login will open in your browser automatically.
Tech Stack
- Go 1.23+ — single binary, zero CGO
- modernc.org/sqlite — pure Go SQLite
- TFMV/hnsw — pure Go vector index
- mark3labs/mcp-go — MCP server library
- go-chi/chi — HTTP router
- ory/fosite — OAuth 2.1
- Svelte 5 + Tailwind — Web UI (embedded)
License
Apache 2.0