Vigil gives your agents persistent awareness, not just memory. Structured session handoff, frame-based tool filtering, a lightweight signal protocol, and an MCP server that works with Claude, Cursor, and anything else — all in a single Python package.
The problem
Every time an agent boots, it starts from zero. No context, no history, no coordination.
Agents forget everything between conversations. Re-reading codebases, re-establishing context, re-making decisions already made — every single time.
MCP servers dump their entire tool list into every context window. In large servers, that's 40–80K tokens per session before the agent does anything useful.
Multi-agent systems have no shared awareness layer. One agent's work is invisible to another. Handoffs fail silently. No signal bus, no event protocol.
What you get
Seven production-grade modules, zero dependencies, single install.
Background process compiles system state into a structured AWARENESS.md every 90 seconds. Agents boot with full context — no cold starts.
Expose only the tools relevant to the current task. Switch frames with a query param. Eliminate 40–80K tokens of noise from every context window.
Lightweight structured signals between agents and systems. Post from anywhere — CLI, Python, HTTP. Queryable signal history. Coordination without queues.
Structured STATE.md written at session end. Next agent — or next session of the same agent — picks up exactly where you left off. No verbal summaries needed.
Vigil watches signals and session logs to extract durable knowledge — patterns, decisions, corrections. Stored and surfaced automatically, not buried.
Built-in MCP server exposes all Vigil tools to any MCP-compatible client. Works out-of-the-box with Claude, Cursor, Windsurf, and any MCP host.
One-line instrumentation for any MCP server. Tracks every tool call — latency, errors, silent failures. Get p95 latency, error rates, and per-tool analytics. Know when your MCP server breaks before your users do.
How it works
No configuration files required to get started. Works with your existing MCP setup.
Single package from PyPI. No dependencies pulled in.
Creates a vigil.db and begins compiling AWARENESS.md every 90 seconds.
Point Claude or Cursor at the SSE URL. Add a frame param to scope tools.
Use cases
Vigil works anywhere agents need shared context, structured handoff, or scoped tool access.
Three agents review the same PR — security, style, and correctness. Each emits signals as they work. The next agent picks up where the last left off via structured handoff.
GitHub Actions emit signals on every deploy. Vigil triggers fire Slack webhooks on failure, add focus items on rollback, and keep your agents aware of production state.
Frame-based filtering gives each agent only the tools it needs. A research agent sees search tools; a writing agent sees document tools. Same MCP server, different frames — 50-90% fewer tokens.
Pricing
The open-source core is always free. Hosted cloud tier is coming Q3 2026.
Free
forever · open source
Pro
cloud hosted · coming Q3
Team
cloud hosted · coming Q3
Enterprise
cloud hosted · coming Q3
How it fits
Vigil is complementary to memory tools. It handles coordination, awareness, and tool scope — the layers that memory libraries don't cover.
| Capability | Vigil | Mem0 | Letta | LangGraph |
|---|---|---|---|---|
| Session awareness / context compile | ✓ | — | partial | — |
| Frame-based tool filtering | ✓ | — | — | — |
| Signal / event protocol | ✓ | — | — | partial |
| Structured session handoff | ✓ | — | partial | partial |
| Vector / semantic memory | — | ✓ | ✓ | — |
| Multi-agent orchestration | signals | — | ✓ | ✓ |
| Native MCP server | ✓ | — | — | — |
| Zero dependencies | ✓ | — | — | — |
Use Vigil alongside Mem0 or Letta — they operate at different layers. Vigil handles coordination and awareness; memory tools handle retrieval.
Open source. Zero dependencies. Works with Claude, Cursor, and any MCP client.