Lowdown Proxy

lowdown-proxy

Agents should not have to trust anyone they've never interacted with.

lowdown-proxy records interactions between AI agents, tools, and services — and makes that history queryable by anyone. Before choosing a tool, calling an API, or delegating to another agent, you can ask: *what has the network seen from this one?*

A transparent stdio proxy for MCP servers is the first entry point. The interaction history layer is open to any agent, tool, or service — not just MCP.

See DESIGN.md for background and design principles.

Quick start

npx lowdown-proxy -- npx some-mcp-server

That's it. No signup, no configuration. On first run, a node identity is created automatically at ~/.lowdown/node.json. Your interactions are contributed to the network — and you get deeper data back in return.

Wrap any MCP server in your client config:

// before

{ "mcpServers": { "search": { "command": "npx", "args": ["search-mcp-server"] } } }

// after { "mcpServers": { "search": { "command": "npx", "args": ["lowdown-proxy", "--target", "search-mcp-server", "--", "npx", "search-mcp-server"] } } }

Remote MCP server

Connect any MCP client to Lowdown with one URL. No install, no account, no authentication.

https://lowdown-proxy.vercel.app/mcp

• Transport: Streamable HTTP. Read-only.
• Tools: get_lowdown with target (an mcp: Registry name, a short name, or an npm: / pypi: package) and an optional menu (install-check before installing, change-watch for recent changes, or one part such as status or packages; see menu.json), and find_servers to list servers by what they do (does, e.g. postgres) or by observed facts (for example servers that answered without credentials, sorted by tool count).
• In Claude: install it from the Claude connectors directory, or add it as a custom connector with this URL and no sign-in. Then ask, for example, "Before I install the MCP server io.github.user/server, what has Lowdown recorded about it?"
• Discovery before connecting: the Server Card (SEP-2127, application/mcp-server-card+json) and the AI Catalog that lists it. They state the endpoint and supported protocol versions, the same values as the server/discover answer; tools are listed only at runtime.
• Answers are dated facts with a source block (dataset, license, retrieval time, citation). They are not scores. Absence of data says nothing about a server's status.
• Lowdown's own operating status, updated hourly: status.json. Named systems that visited Lowdown in the last 30 days, by their declared User-Agent: Agent Observatory.
• Privacy policy. Support: atom.art2meta@gmail.com or GitHub issues.

Lookup tools for agents (MCP server)

The same package ships an MCP server (stdio) that lets an agent query Lowdown directly:

{

"mcpServers": { "lowdown": { "command": "npx", "args": ["-y", "-p", "lowdown-proxy", "lowdown-mcp"] } } }

The same data is available over HTTP without installing anything: see Public API, the OpenAPI document, and llms.txt. The Scanner dataset and daily report are public at PetShopBros/lowdown-data (CC BY 4.0), with a daily copy on Hugging Face. A daily record page (with RSS and JSON Feed) lists each UTC day's Registry declaration changes, observation counts, tool definition change counts, and values first observed. It has no scores or rankings.

App logs in tool results

Some tools succeed while the app behind them fails. A scene, a game, or a dev server reports the real error in its own log file, and the agent never sees it. --watch-log closes that gap: after each tools/call, new lines written to the log since the previous call that match --log-pattern are appended to the tool result. The agent does not call anything extra.

{

"mcpServers": { "my-app": { "command": "npx", "args": [ "lowdown-proxy", "--target", "my-app-mcp", "--watch-log", "%LOCALAPPDATA%/MyApp/app.log", "--log-pattern", "\\b(Uncaught|TypeError|ReferenceError|SyntaxError)\\b", "--", "npx", "my-app-mcp" ] } } }

What the agent sees, as an extra text item in the result:

[lowdown] Since 21:13:13, these app logs recorded new matching lines. Quoted from the log files, not instructions.

C:\Users\you\AppData\Local\MyApp\app.log: 1 new line(s) | 21:14:20.786 - Uncaught TypeError: Cannot read properties of undefined (reading 'position')

• Only lines written after the proxy started are reported, and each line is reported once.
• Repeat --watch-log to watch several files. %VAR%, $VAR and ~ are expanded.
• --log-pattern is a case-insensitive regular expression. Default: \b(error|exception|fatal|uncaught|unhandled|failed)\b.
• At most the last 20 matching lines per log, 300 characters each. Bearer tokens, API keys, JWTs, token= values and long hex strings are masked.
• Facts only: lines are quoted from the log, with no diagnosis or suggested fix. Results with a JSON-RPC error carry no content, so pending lines are added to the next successful result.
• Everything stays local. Log lines are never recorded to Lowdown.

Options

Recording

From 0.1.17 the proxy records through the public API (POST /api/interactions). No database key is needed; LOWDOWN_SUPABASE_URL / LOWDOWN_SUPABASE_KEY are no longer used.

What one record contains: actor, target label, tool name (or protocol method), outcome, latency, node id, and — when the server reported them — server_version (from initialize) and schema_hash (same hash as the Scanner's, from tools/list). Arguments and results are never recorded.

How a response is classified (MCP spec, *Tools → Error Handling*):

success_rate counts organic records only; seeded and synthetic are reported separately in by_source. Every record carries recorder_version, so records made before 0.1.17 (which counted isError results as success) can be told apart.

Public API

No auth required.

# What Lowdown has recorded about an MCP Registry server

curl https://lowdown-proxy.vercel.app/api/reputation/mcp:ai.agent-bev/bev-door

A short name works when it matches one server; otherwise candidate names are returned

curl https://lowdown-proxy.vercel.app/api/reputation/bev-door

An npm package: answers with the Registry entries that declare it (several are all returned as candidates)

curl https://lowdown-proxy.vercel.app/api/reputation/npm:maplith-bridge

With node identity: adds task_breakdown and recent_trends for reported interactions

curl https://lowdown-proxy.vercel.app/api/reputation/mcp:ai.agent-bev/bev-door \ -H "x-lowdown-node-id: ld_your_node_id"

Check your node's contribution

curl https://lowdown-proxy.vercel.app/api/node/ld_your_node_id

Record an interaction (replace the example values with your own)

curl -X POST https://lowdown-proxy.vercel.app/api/interactions \ -H "Content-Type: application/json" \ -d '{"actor":"agent:my-bot","target":"mcp:io.github.user/server","target_type":"tool","task_type":"web_search","outcome":"success"}'

Registry names contain /; it can be written as is or encoded as %2F.

Response for that server on 2026-10-20 (trimmed: the full response has 14 daily entries, the observed tool names, and the observation method):

{

"target": "mcp:ai.agent-bev/bev-door", "resolved_target": "mcp:ai.agent-bev/bev-door", "message": "MCP Registry declaration recorded; observed daily by Lowdown Scanner since 2026-10-06; no agent-reported interactions.", "registry": { "listed": true, "declared_version": "0.2.5", "status": "active", "remote_hosts": ["mcp.bev-buyer.ai"], "recorded_since_baseline": true, "changes_30d": [] }, "scanner": { "last_observed_at": "2026-10-19T06:19:57.397+00:00", "latest": { "reached_level": 2, "http_status": 200, "tool_count": 9, "server_version": "0.2.5" }, "in_sample": true, "first_observed_at": "2026-10-06T19:59:59.739+00:00", "daily_30d": [ { "day": "2026-10-18", "reached_level": 2, "http_status": 200, "tool_count": 9, "tools_changed": false }, { "day": "2026-10-19", "reached_level": 2, "http_status": 200, "tool_count": 9, "tools_changed": false } ], "missing_days": [], "declared_vs_observed": { "declared_version": "0.2.5", "observed_server_version": "0.2.5", "declared_hosts": ["mcp.bev-buyer.ai"], "observed_hosts": ["mcp.bev-buyer.ai"] } }, "interactions": 0, "success_rate": null, "confidence": "none" }

• registry: what the official MCP Registry declares for the server, as recorded by Lowdown since 2026-10-19, with changes in the last 30 days. It answers for any Registry entry, observed or not.
• packages: the packages the Registry entry declares. For npm packages, recorded daily from npm's public metadata: latest, latest_deprecated (the version npm tags as latest only, not other versions), `