Observability

• Health: GET /healthz answers 200 when the server is up.
• Startup log: the release and commit, every setting changed from its default, and a WARNING for a rate limit set far looser than its default or a RATE_LIMIT_* name that is not a setting (a typo). On a small box: cd /opt/simple-host && sudo docker compose logs app.
• Admin page (/admin, admin key): disk use, the running release, every account and site, API traffic by route and caller, and the saved-data watch.
• Visit analytics per site come from the web server’s access log, not a tracking script. Visitor addresses are hashed with a salt; where a caller is comes from a database on the server, never a lookup elsewhere.

Setting	Default	Allowed	What it does
ANALYTICS_PAGES_PER_SITE_DAY	200	10–10000 pages	Distinct pages a site’s Top pages keeps per day; views of further new pages that day are counted together as (other).
ANALYTICS_REFERRERS_PER_SITE_DAY	100	10–10000 domains	Distinct referring domains a site keeps per day; further new domains that day are counted together as (other).
NETWORK_MONTHLY_ALLOWANCE_GB	10240	0–10000000 GB	The box’s free outbound data a month, in GB (1 TB = 1024 GB), which the admin page’s network bar measures this month’s outbound against. 10240 is Oracle Cloud Always Free’s 10 TB. 0 hides the bar.
NETWORK_ALERT_PCT	75	1–100 percent	The share of NETWORK_MONTHLY_ALLOWANCE_GB at which the admin page’s network bar turns amber, and the box’s daily watch script sends its one alert of the month.
NETWORK_SAMPLE_MINUTES	60	1–1440 minutes	How often the box’s network counters are added to the month’s totals. The admin page adds the growth since the last sample itself, so this only bounds what a reboot can lose.
API_METRICS_FLUSH_SECONDS	20	5–3600 seconds	How often counted API calls are written to the database for the admin page’s API traffic and growth. Calls counted since the last write are lost if the server stops abruptly.
AGENTCAT_PROJECT_ID	none	text	AgentCat project for MCP tool-call events (arguments, results, and stated intent, with secrets and file contents left out); empty disables sending.
PAPER_METRICS	on	on / off	Collects local paper metrics; off, false or 0 disables collection.
ANALYTICS_LOG	none	text	The web server’s access log that visit analytics are read from. Empty: no analytics.
ANALYTICS_SALT	none	secret	Salt for the hashed visitor addresses in analytics. Empty: derived from ADMIN_API_KEY. Security-sensitive.
NETWORK_INTERFACE	<default route>	text	The network interface whose traffic the admin page reports as the box’s own. Empty: the one the default route leaves by. Inside a container, where that is the container’s own, network use is off unless this is set.
GEOIP_DIR	<DATA_DIR>/../geoip	text	Where the local location databases are. Missing files mean blank locations, never a lookup elsewhere.

AgentCat tool-call context

Hosted Simple Host sends the existing usage fields plus arguments and results (8 KB of JSON for each) and stated intent (2,048 characters). Other installations are not enrolled. The optional context input appears whenever analytics is enabled, for every caller including ChatGPT, OpenAI, and Codex connections (owner, 2026-10-29). It is removed before validation unless the tool defines its own context. Wrapped calls use the inner operation’s arguments and intent, with outer intent as a fallback. Arguments are sanitized once. Unknown or retired targets, forbidden discovery targets (run_tool and find_tools), and non-object inner arguments send parameters: {"arguments": "[removed]"}. The resource name and error reporting stay unchanged. Non-string context is also removed before validation, but only a string becomes intent.

The sender makes a separate copy before enqueueing. Its field inventory, checked against the connector schemas and outputs on 2026-10-29, is:

• Secrets: field names containing passcode, password, secret, token, apikey, authorization, or cookie after lowercasing and removing underscores and hyphens; also code, signincode, verificationcode, teamkey, signingkey, and privatekey. This includes passcode_protected and passcode_set_at under the requested name rule. auth_header is removed as a whole because its credential is in a child named value. Webhook signing secrets are carried by REST and events/subscribe, not current tool-call results; secret is covered structurally.
• Links: upload_url, photos_url, import_url, download_url, signed_url, preview_url, pinned_url, join_url, judge_url, and invite_url, plus join_code and judge_code. create_upload_link.how is removed because its curl command repeats the signed URL.

The client’s text, structured result, and metadata are unchanged. UI metadata is not included in telemetry.

The SDK’s image, audio, binary-resource, unknown-content, and large-base64 placeholders run after these removals. The structural walk stops at 32 levels with [Object] before further descent. Depth 10, breadth 100, and string truncation with ... run next, with progressively smaller limits until each JSON field fits in 8,192 bytes. The event’s error remains the short server code; the response includes the tool’s error result. Request headers are not captured. AgentCat never receives the IP address a person connects from.

The SDKs have no built-in personal-data scrubber. AgentCat’s project redaction removes personal identifiers before storage. No local email, URL, credential-content, or other personal-data pattern matching is used. Arbitrary prose, SQL aliases, and user-defined fields outside this inventory rely on that server-side redaction. The local tests verify what is posted, not AgentCat’s storage or project configuration.

Network and page counts

The admin Overview shows the box’s bytes in and out this month from the main interface’s kernel counters, sampled into the database, and website bytes sent from the analytics log’s ninth field ($bytes_sent). Traffic rows follow ANALYTICS_RETENTION_DAYS. Setting NETWORK_MONTHLY_ALLOWANCE_GB=0 also disables the alert. The daily alert script is deploy/prod/sh-network-watch.sh.

Top-page paths are normalized before counting: percent escapes decoded once, // collapsed, query and fragment dropped. The referrer-domain cap bounds referrer spam. Local location files are DB-IP Lite databases.