art2meta/lowdown-mcp-observations

Lowdown MCP Registry Observations

Lowdown is a time-series record of the gap between what the official MCP Registry declares and what is actually observed. It records what changed and when. It does not score, grade, or rank servers.

This dataset holds the raw observation records of the Lowdown Scanner. It is a periodic copy of PetShopBros/lowdown-data on GitHub, where the daily report and the latest data are published first.

Contents

Path	What it is	Updated
REPORT.md	Summary of the most recent Scanner run and the last few runs	Regenerated from the database after Scanner runs
scanner_observations/YYYY-MM.csv	Raw observation records, one file per month (UTC)	Weekly; the last two months are re-exported each time
LICENSE	CC BY 4.0

What the Scanner observes

• Population: a fixed sample of 2,000 entries (cohort 2026-10-07-v1) selected once from the official MCP Registry and unchanged since. These are Registry entries, not operators, and they do not represent the whole Registry. Only entries with a streamable-http remote are in scope; stdio-only servers are not observed.
• Requests: initialize and tools/list only. The Scanner never calls a tool and does not authenticate.
• Frequency and location: once per day, from a single network location (GitHub Actions).
• Redirects are not followed. 401 and 403 are recorded as the status observed, not as success or failure.
• Retries: probes that fail in a way that may be temporary (timeout, connection refused or reset, HTTP 408, 429, 5xx) are tried once more a few minutes after the run, one request per host at a time. The retry result is added to the same row under metadata.retry. The first-attempt columns are never changed. Rows recorded before retries were introduced have no retry key.
• Registry fallback: on a day when the Registry list cannot be fetched, the Scanner observes the same cohort using the remote URLs from the previous run. Those rows carry metadata.registry_fallback: true with registry_snapshot_run and registry_snapshot_at, and that day's Registry changes are not reflected.

These are single probes. They describe reachability at one moment, not availability or uptime.

CSV columns

Column	Meaning
id	Row id (ascending)
scan_run_id	One id per Scanner run
node_id	Id of the observing Scanner node
target_id	mcp: + Registry server name
target_type	Always mcp_server
observed_at	Time of the first attempt (UTC)
transport	Remote transport type (streamable-http)
http_status	HTTP status of the last response received; empty if no HTTP response
reached_level	0 initialize did not complete, 1 initialize completed and tools/list did not, 2 both completed
latency_ms	Latency of the initialize request
error_type	Set only when no HTTP response was received (timeout, dns, tls, conn_refused, conn_reset, network_error), the URL was not called (blocked_url), or a 2xx response was not valid JSON-RPC (invalid_response)
source	Always scanner
metadata	JSON with additional facts, listed below

Common metadata keys: remote_url, remote_index, registry_version, scanner_version, cohort_version, registry_fallback, init_status, list_status, list_latency_ms, list_error_type, protocol_version, server_version, session_id_issued, tool_count, tools_has_more, schema_hash (tool names and input/output schemas), desc_hash (tool names, titles and descriptions), rpc_error_code, www_authenticate, www_authenticate_resource_metadata, and retry (retried_at, reached_level, http_status, error_type, latency_ms, per_host_concurrency). Tool descriptions themselves are not stored, only their hash.

License and citation

The data and REPORT.md are licensed under CC BY 4.0. You may share and adapt them for any purpose, including commercial use, with attribution.

Suggested attribution:

Lowdown Scanner data (PetShopBros/lowdown-data), CC BY 4.0, https://github.com/PetShopBros/lowdown-data

Source

The Scanner code is in PetShopBros/lowdown-proxy (scanner/).