hyperhive/docs/observability.md

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# Observability (OpenTelemetry)
hyperhive has built-in support for exporting per-agent Claude Code statistics —
token usage, cost, tool call counts — to any OTLP-compatible collector via
Claude Code's built-in OpenTelemetry integration.
This is a **hive-wide** setting: one switch in the host NixOS config enables it
for every agent container simultaneously. There is no per-agent opt-in or opt-out.
## Enabling export
```nix
services.hyperhive.otel = {
enable = true;
endpoint = "https://collector.example.com/otel";
};
```
`enable` is the single gate. `endpoint` (required when enabled) is the OTLP
HTTP endpoint; hive-c0re injects it as `OTEL_EXPORTER_OTLP_ENDPOINT` into
every agent's systemd service via the generated meta flake.
Each agent's harness (hive-ag3nt) exports directly to the collector — the
pipeline keeps working even when hive-c0re is down.
## Options reference
### `services.hyperhive.otel.enable` — bool, default `false`
Master switch. When true, all other options below take effect.
### `services.hyperhive.otel.endpoint` — string, required when enabled
OTLP collector endpoint URL. Set as `OTEL_EXPORTER_OTLP_ENDPOINT` for every
agent. Example: `"https://collector.example.com/otel"`.
### `services.hyperhive.otel.protocol` — enum, default `"http/protobuf"`
OTLP wire protocol, passed as `OTEL_EXPORTER_OTLP_PROTOCOL`. Accepted values:
- `"http/protobuf"` (default)
- `"http/json"`
- `"grpc"`
### `services.hyperhive.otel.headersCredential` — string or null, default `null`
Absolute path to a secret file on the host whose contents become
`OTEL_EXPORTER_OTLP_HEADERS` (e.g. `Authorization=Bearer <token>`).
hive-c0re forwards this host file into each agent container via
`systemd-nspawn --load-credential=otel-headers:<path>`; the inner harness unit
inherits it by name. The token is never copied into the nix store, generated
config, a bind mount, or argv.
Leave `null` if the endpoint needs no auth header. A configured-but-missing
file is skipped with a log warning — OTEL still exports, just without the auth
header.
```nix
services.hyperhive.otel = {
enable = true;
endpoint = "https://collector.example.com/otel";
headersCredential = "/run/secrets/otel-headers";
};
```
### `services.hyperhive.otel.extraResourceAttributes` — string, default `""`
Extra comma-separated entries appended to `OTEL_RESOURCE_ATTRIBUTES` after the
built-in labels (`service.name`, `agent`, `hive`, `swarm`). Example:
```nix
extraResourceAttributes = "deployment.environment=prod,team=platform";
```
### `services.hyperhive.otel.debug` — bool, default `false`
When `true`, sets `CLAUDE_CODE_OTEL_DIAG_STDERR=1` in every agent container,
causing the OTEL SDK to emit diagnostic messages to stderr. Useful when
troubleshooting collector connectivity or endpoint config errors. Leave `false`
in normal operation — SDK errors from a misconfigured endpoint would otherwise
appear in every agent's journal unconditionally.
Only meaningful when `enable` is true.
### `services.hyperhive.otel.metricIntervalMs` — positive int or null, default `null`
Metric export interval in milliseconds, set as `OTEL_METRIC_EXPORT_INTERVAL`
for every agent. Claude Code's default is 60000 (60 s). Leave `null` to keep
that default.
Each agent runs claude as a short-lived per-turn process; claude force-flushes
metrics on process exit, so interval tuning is not required for metrics to be
exported. A lower value gives more frequent intermediate flushes within
long-running turns — cosmetic, not a correctness knob.
## Network access
Agent containers can only reach the host on ports 80 and 443 by default. If
your OTLP collector runs on a non-standard port on the same host (e.g. a local
dev collector on `:4318`), open that port via:
```nix
services.hyperhive.network.exposeHostPorts = [ 4318 ];
```
Then point the endpoint at the bridge IP rather than loopback:
```nix
services.hyperhive.otel.endpoint = "http://10.42.0.1:4318";
```
The bridge IP is the host's address on the `hvbr0` bridge, typically
`10.42.0.1`. See `docs/network.md::Reaching host services` for details.
## Built-in resource labels
Every agent's export includes these resource attributes automatically:
| Attribute | Value |
|-----------|-------|
| `service.name` | `hyperhive-agent` (constant) |
| `agent` | agent logical name (e.g. `iris`) |
| `hive` | hive display name (`services.hyperhive.hiveName`) |
| `swarm` | swarm display name (`services.hyperhive.swarmName`, if set) |
Additional labels can be appended via `extraResourceAttributes` (see option
reference above); custom per-data-point labels can be passed with
`hive-metric --labels` (see below).
## Agent-emitted custom metrics (`hive-metric`)
Agents can push arbitrary labeled metrics to the same OTEL collector via the
`hive-metric` CLI tool, available in every agent container when
`services.hyperhive.otel.enable = true`.
### Usage
```text
hive-metric <name> <value> [--type counter|gauge] [--labels key=value...]
```
- `<name>` — metric name (e.g. `tasks_completed`, `latency_ms`).
- `<value>` — numeric value (f64; integers and floats both accepted).
- `--type counter|gauge` — metric kind: `counter` (cumulative sum, default) or
`gauge` (instantaneous point-in-time value).
- `--labels key=value` — extra per-data-point labels. May be repeated.
The resource labels (agent, hive, swarm, service.name) are inherited
automatically from `OTEL_RESOURCE_ATTRIBUTES` — do not re-specify them.
### Examples
```text
# Counter: cumulative tasks finished (default type — no --type flag needed)
hive-metric tasks_completed 1 --labels phase=scan
# Gauge: current queue depth (absolute value — must use --type gauge)
hive-metric queue_depth 17 --type gauge
# Float gauge with multiple labels (instantaneous measurement)
hive-metric api_latency_ms 142.5 --type gauge --labels model=sonnet --labels tier=api
```
### Error when OTEL is not configured
When `services.hyperhive.otel.enable = false` (the default), the
`OTEL_EXPORTER_OTLP_ENDPOINT` env var is not set and `hive-metric` exits
with an informative error message. No silently-dropped metrics.
### Wire format
`hive-metric` always uses **OTLP HTTP/JSON** (`application/json` POST to
`$OTEL_EXPORTER_OTLP_ENDPOINT/v1/metrics`), regardless of the
`OTEL_EXPORTER_OTLP_PROTOCOL` setting. Auth headers from
`OTEL_EXPORTER_OTLP_HEADERS` are forwarded verbatim.
## Metrics temporality
OTEL export is always configured with **cumulative** temporality
(`OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE=cumulative`),
overriding Claude Code's default of DELTA. This avoids silent metric drops in
Prometheus-family backends (including Grafana LGTM / Mimir) that don't ship a
delta-to-cumulative processor.