diff --git a/README.md b/README.md
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+++ b/README.md
@@ -11,6 +11,8 @@ This repo is where you deploy and operate it. The code lives in
 The proposed paired backend, basic Atlas and Topology release is described in
 [Core performance candidate](docs/performance-release-candidate.md), including
 validation, operational budgets and remaining release gates.
+The separate [optional collection guide](docs/telemetry-collection.md) covers
+mobile/headless clients, intake, sensor cards and their qualification gates.
 
 > **Coming from 1.x?** 2.0.0 needs a fresh database and a few config changes. Read
 > [Upgrading](docs/upgrading.md) before you pull new images.
diff --git a/docs/telemetry-collection.md b/docs/telemetry-collection.md
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@@ -0,0 +1,138 @@
+# Optional companion telemetry collection
+
+Enable this alongside the core performance, basic Atlas and Topology candidate
+only when the intake service and client qualification are ready. Basic Atlas,
+Topology and ordinary observer telemetry continue to work without it.
+
+## Components
+
+| Component | Responsibility |
+| --- | --- |
+| Beacon Flutter app | User-selected BLE or Wi-Fi/TCP companion, saved repeater selection, optional local password/admin requirement, polling budgets and signed delivery |
+| Beacon server | Optional bounded proxy and `/info` capability for the selected instance |
+| Telemetry intake | Automatic enrollment validation, sample validation/deduplication, quotas, separate storage, retention, history and availability |
+| Beacon web | Repeaters-with-telemetry filter, attributed battery/environmental series and explicit gaps/partial history |
+| Headless Collector | Alternate polling client for unattended USB/BLE use; it uses the same intake contract |
+
+The app replaces the user-operated polling client, not the intake/storage service.
+The current intake is packaged in the separate Collector project. The org
+`beacon-agent` scaffold is not a deployable replacement for that implementation.
+Software distribution/access for the alpha is separate from client enrollment:
+there is no per-user operator approval list.
+
+## Enable an instance
+
+Run intake with its own PostgreSQL database. Its canonical `COLLECTOR_INSTANCE`
+must equal the HTTPS Beacon URL the app selects, including any installation
+subpath and excluding a trailing slash, query string or credentials. A session
+issued for the Canadaverse preview is not a session for another Beacon instance.
+
+Point the optional server setting at the intake over the private service network:
+
+```yaml
+node_telemetry:
+  gateway_url: http://collector:8081
+```
+
+Replace `collector` with that deployment's actual private service hostname. The
+public client uses the Beacon instance's existing HTTPS API. The core proxy
+accepts only the enrollment/report/read routes, bounds bodies/responses/deadlines,
+does not follow redirects and does not forward caller cookies or authorization
+headers. Set the intake's trusted proxy CIDR to the core app's actual private
+peer address; never trust a caller-provided forwarding header unconditionally.
+
+When configured, `/api/v1/info` includes `collectedNodeTelemetry: true`. This is
+a capability statement, not an assertion that every companion or sensor is
+currently healthy. If intake is disabled, optional history is unavailable and
+basic cards still work. A configured service failure must remain a visible,
+retryable error rather than an empty successful collection.
+
+## Client workflow
+
+In the app, select the Beacon instance, open Telemetry sharing, connect the
+companion, choose saved repeaters and an interval from 1 to 72 hours. Optional
+repeater/admin passwords stay on the client. The companion private key is never
+exported. First use starts with flood discovery; subsequently learned routes are
+used within the client's hop/congestion policy. Environmental decoding preserves
+channel numbers, including channel 2, and explicit zero values.
+
+The mobile client reserves attempts before transmitting, applies a shared
+two-attempt/six-command hourly companion budget and checks airtime/queue state.
+An interval is a minimum; selecting more nodes can make the effective interval
+longer. Upload retries resend the same saved report and do not poll again.
+There is no automatic burst to catch up missed RF intervals.
+
+For Android, background collection is an explicit remembered choice. The
+connected-device service has an ongoing notification with Stop/Disconnect
+actions and optional counts. Expired saved reports are counted separately from
+accepted reports. Loss of the connection/process stops collection; a foreground
+service is not an exact-time or uninterrupted-work guarantee. iOS collection is
+foreground-only in this draft.
+
+No global cross-instance RF lease or hardware attestation is claimed. Cooperating
+clients still need coordination before a broad rollout. The server validates
+key possession and report structure; public data remains attributed community
+measurements rather than independently verified sensor truth.
+
+## HTTP and MQTT acceptance
+
+The version-1 routes are under `/api/v1/node-telemetry`:
+
+| Method/path | Contract |
+| --- | --- |
+| POST `/challenge` | Short-lived instance/radio/client-bound challenge |
+| POST `/enroll` | Both companion and client sign the prefixed challenge; returns an intake session |
+| POST `/reports` | Validates the signed sample and returns acceptance only after storage/deduplication |
+| GET `/availability` | Full node keys with retained data, 30-day retention and explicit directory truncation |
+| GET `/{full-public-key}` | At most 500 retained samples, chronological output, cap/coverage metadata |
+
+Sample IDs are idempotent only for identical validated samples. A reused ID with
+different data is rejected. Session secrets currently rotate when intake restarts;
+clients re-enroll and retry the same queued sample, preserving RF cooldowns.
+
+The app uses HTTPS. The headless client's optional MQTT publish is followed by
+idempotent HTTPS confirmation of the same signed sample. Broker PUBACK alone
+does not remove the outbox. This protects against an unavailable consumer or an
+intake rejection without adding an RF request. MQTT still needs the existing
+enrollment API and appropriate topic/TLS credentials.
+
+## History, capacity and retention
+
+History responses include `limit`, `truncated`, `retentionDays`, `windowStart`
+and `windowEnd`. A cap is not a complete 30-day history. The web labels partial
+history and keeps missing measurements distinct from zero; dashed bridges are
+visual estimates, not new samples. Full node keys separate identities and
+collector/radio attribution keeps different sources from silently joining.
+
+Availability is coalesced and cached for at most a minute, invalidated by new
+accepted reports and retention maintenance. Concurrent first reads share one
+bounded aggregation. Default intake pool capacity is four connections unless an
+operator explicitly overrides it; budget these alongside core pools.
+
+Retention runs in short minute-spaced passes, with a five-second context and at
+most four indexed batches of 5,000 expired rows. Monitor the oldest retained
+timestamp/backlog on larger deployments. The separate
+`collector_schema_migrations` ledger records intake initialization; it is not a
+core Beacon migration. Keep core and intake backup/recovery identities distinct.
+
+## Qualification and deployment gates
+
+Use the exact paired optional server/web commits above the accepted core stack,
+the matching app branch and the identified intake build. Do not merge an older
+telemetry PR wholesale over newer config, read-model or virtualization changes.
+
+Validate signatures, instance binding, null/range handling, replay/different-data
+IDs, concurrent quotas, expiry, history/directory caps, cache invalidation and
+outage recovery on an isolated database. Synthetic signed samples belong in that
+isolated test instance, not in the shared preview's public repeater history.
+
+Then verify the preview's actual retained data, API proxy, web filter/cards and
+normal collector acceptance without resetting RF cooldowns. Preserve the
+exclusive radio lease and unrelated services during updates. Check before/after
+source/binary/asset hashes, database/configuration identity and recovery copies.
+
+Physical qualification remains separate: a real selected companion/repeater,
+status plus channel-2 readings, intake acceptance, matching Atlas display, locked
+screen intervals, notification actions and transport/network failure. The current
+consolidation found no Android device attached, so these new physical runs are
+not claimed. Build/unit/API success does not replace them.