@argosvix/mcp-server

Argosvix MCP server lets AI agents (Claude Desktop, Cursor, Codex CLI, custom MCP clients) query, manage, and operate their LLM observability data directly from the conversation. Supports both stdio (subprocess) and HTTP (remote / self-host) transports.

Surface: 89 tools (86 generally available + 3 internal operations tools that return 403 for customer accounts) / 3 resources / 8 resource templates / 3 prompts. Health and anomaly endpoints (get_account_health / detect_anomaly / propose_alert_rules / classify_calls_batch / propose_eval_criteria) plus a runtime control plane (budget gates / policy gates / human-approval gates) let an agent both observe and act. Release history is available on npm.

Why

You're already sending LLM calls through @argosvix/sdk or the Python SDK. Now ask Claude / Cursor questions like:

• "What was my OpenAI cost over the past 24h?"
• "Which alerts are firing right now?"
• "Show me the 20 most expensive calls today."

No dashboard tab-switching. The agent fetches the data via this MCP server using your Argosvix API key.

Install

One-click (starts keyless; set ARGOSVIX_API_KEY afterwards to use the tools for your own account):

Claude Code users can install the argosvix plugin instead — it bundles this server plus setup skills:

/plugin marketplace add argosvix/claude-plugin
/plugin install argosvix@argosvix
/reload-plugins

Manual:

npm install -g @argosvix/mcp-server

Configure (Claude Desktop)

Edit your Claude Desktop config:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "argosvix": {
      "command": "argosvix-mcp",
      "env": {
        "ARGOSVIX_API_KEY": "argk_..."
      }
    }
  }
}

Restart Claude Desktop. All 89 tools appear under the argosvix__ prefix (e.g. argosvix__query_calls, argosvix__get_account_health, argosvix__create_budget_gate).

No API key yet? The server also starts without ARGOSVIX_API_KEY in introspection-only mode: all 89 tools are listed so you can evaluate the surface, and two public data tools (get_synth_daily / get_daily_readthrough — Argosvix's own daily AI digest and OSS readthrough) work with no key at all. Every other tool call returns instructions for getting a key at https://dashboard.argosvix.com/api-keys.

Notes on the public data tools: they are part of the default full profile only (not in ARGOSVIX_MCP_PROFILE=core), and like every other tool they honor ARGOSVIX_API_BASE — if you point the server at a different base, they fetch /v1/synth-daily / /v1/readthrough from that base without authentication.

Configure (Cursor)

Edit ~/.cursor/mcp.json:

{
  "mcpServers": {
    "argosvix": {
      "command": "argosvix-mcp",
      "env": {
        "ARGOSVIX_API_KEY": "argk_..."
      }
    }
  }
}

Tool profile (ARGOSVIX_MCP_PROFILE)

The default profile is full (all 89 tools). If your MCP client's context budget is tight, set ARGOSVIX_MCP_PROFILE=core to expose only the 11 essentials for day-to-day operations:

query_calls · aggregate_calls · get_cost_summary · get_percentiles · get_account_health · detect_anomaly · list_alerts · create_alert · silence_alert · unsilence_alert · get_deployed_prompt

{
  "mcpServers": {
    "argosvix": {
      "command": "argosvix-mcp",
      "env": {
        "ARGOSVIX_API_KEY": "argk_...",
        "ARGOSVIX_MCP_PROFILE": "core"
      }
    }
  }
}

Works in both stdio and HTTP transports. Unknown values fall back to full with a warning on stderr.

Description language (ARGOSVIX_MCP_LANG)

Tool, resource, and prompt descriptions returned by tools/list / resources/list / prompts/list are in English by default. Set ARGOSVIX_MCP_LANG=ja to get the original Japanese descriptions instead. Unset or unknown values fall back to en (with a warning on stderr for unknown values). Tool names, input schemas, and behavior are identical in both languages — only the human/agent-facing description text changes.

{
  "mcpServers": {
    "argosvix": {
      "command": "argosvix-mcp",
      "env": {
        "ARGOSVIX_API_KEY": "argk_...",
        "ARGOSVIX_MCP_LANG": "ja"
      }
    }
  }
}

Works in both stdio and HTTP transports.

Tools (highlights)

89 tools in total — the full list is returned by tools/list. A sample of the core read / write surface:

Resources

Resources expose read-only snapshots that AI agents can pull into context without an explicit tool call.

Resource templates

Resource templates let agents construct dynamic URIs from a known id. The server enforces account scope via PK lookup on the backend, so cross-account ids return 404.

Prompts

Prompts are reusable templates the user can launch as slash commands.

Subscriptions (= v0.10, stdio only)

resources.subscribe capability is declared in stdio mode. Clients can subscribe to one or more of the static resources below; the server polls each subscribed resource every 60 seconds and emits notifications/resources/updated when the content hash changes.

Subscribable URIs (resource templates such as argosvix://calls/{id} are not subscribable):

• argosvix://account
• argosvix://alerts/active
• argosvix://cost/today

HTTP transport (= argosvix-mcp --http) does not declare subscribe and rejects subscribe requests, since per-request stateless mode cannot keep a subscription set or deliver server-initiated notifications. Use stdio for live updates.

listChanged is intentionally not declared: the resource list is fixed for the server lifetime.

Implementation notes (v0.10):

• Single-flight guard: a slow polling cycle does not start a concurrent next cycle (= no overlapping readResource calls).
• Unsubscribe / shutdown race: per-URI re-check before fetch and before notify, plus an isShuttingDown flag, so notifications are not emitted for URIs removed mid-cycle.
• Failure handling: fetch and notify failures are silent (next cycle retries). With ARGOSVIX_MCP_DEBUG=1 the server logs { uri, errorClass } to stderr — error messages are intentionally not logged to avoid leaking upstream payload text.
• Tests: 150 unit tests (incl. overlap single-flight + unsubscribe / shutdown race + invalid URI → McpError(InvalidParams) + axis 4 Tier 1 dispatcher coverage).

Privacy

The MCP server sends queries to https://ingest.argosvix.com using your API key. No prompts or completions are exposed — only metadata (tokens, cost, latency, model name, your tags).

Development

npm install
npm run build
npm test

License

MIT © Yuto Makihara (Argosvix). See LICENSE.

HTTP transport

The server can also run as a remote MCP endpoint over HTTP, suitable for self-hosting or multi-tenant scenarios where API key is supplied per request.

# Start HTTP transport (default: 127.0.0.1:3000)
argosvix-mcp --http

# Bind to all interfaces with custom port + allowed Host headers
MCP_HTTP_HOST=0.0.0.0 \
MCP_HTTP_PORT=4000 \
MCP_HTTP_ALLOWED_HOSTS="mcp.example.com,localhost:4000" \
  argosvix-mcp --http

Endpoints

• GET /health → 200 OK with server name/version (no auth)
• POST /mcp → MCP JSON-RPC endpoint (auth required)

Client example

curl -X POST http://localhost:3000/mcp \
  -H "Authorization: Bearer argk_..." \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/list",
    "params": {}
  }'

Auth model

Each request must include Authorization: Bearer <api-key> with a valid Argosvix API key (issue at https://dashboard.argosvix.com/api-keys). The server uses stateless mode (no session ID), so each request is independent and may carry a different key.

Security notes

• Default bind is 127.0.0.1 (localhost only). Use MCP_HTTP_HOST=0.0.0.0 to expose externally, but pair with a reverse proxy + TLS in production.
• DNS rebinding protection is applied for localhost binds by checking the Host header against a known-localhost allow list. Use MCP_HTTP_ALLOWED_HOSTS (comma-separated) when binding non-locally.
• Body size is capped at 1 MiB.

Debug logging

Backend error response bodies are not logged by default to keep production log aggregators free of backend-internal payloads. To enable raw body logging for a debugging session:

ARGOSVIX_MCP_DEBUG=1 argosvix-mcp           # stdio mode
ARGOSVIX_MCP_DEBUG=1 argosvix-mcp --http    # HTTP mode

Without the env var, error logs only include path, status, and x-request-id.