hermes-agent/plugins/platforms/photon/README.md
Teknium 5b4e431e8c feat(gateway): add Photon Spectrum (iMessage) platform plugin
First-class iMessage support via Photon's managed Spectrum platform.
Targeted as a successor to the BlueBubbles adapter — Photon allocates
the iMessage line, handles delivery, and abuse-prevention so users
don't have to run their own Mac relay. Free tier uses Photon's shared
line pool.

Architecture:
- Inbound: signed JSON webhooks (X-Spectrum-Signature, HMAC-SHA256)
  delivered to a local aiohttp listener. Dedupes on message.id,
  rejects deliveries with >5min timestamp drift.
- Outbound: small supervised Node sidecar that runs the spectrum-ts
  SDK. Photon does not currently expose a public HTTP send-message
  endpoint; the sidecar is the only way to call Space.send() today.
  When Photon ships an HTTP send endpoint we collapse the sidecar
  into _sidecar_send and drop the Node dep — every other layer of
  the plugin stays the same.
- Setup: 'hermes photon login' runs the RFC 8628 device-code flow;
  'hermes photon setup' creates a Spectrum-enabled project, creates
  a shared user (free tier), installs the sidecar's npm deps.
- Webhook management: 'hermes photon webhook register|list|delete'.
- Credentials persisted under credential_pool.photon /
  credential_pool.photon_project in ~/.hermes/auth.json.

Plugin path (not built-in) — per current policy (May 2026), all new
platforms ship under plugins/platforms/. Registers itself via
ctx.register_platform() + ctx.register_cli_command(), zero edits to
core gateway code.

Tests cover:
- HMAC-SHA256 signature verification (happy path, tampered body,
  wrong secret, drift, missing v0 prefix, empty inputs, non-integer
  timestamp)
- Inbound dispatch for text DMs, group ids (any;+;...), and
  attachment metadata markers
- Deduplication window
- check_requirements gating when Node is absent
- Device-code flow: request, header-based token return,
  body-fallback token return, access_denied propagation
- Project/user/webhook API clients with mocked httpx

Known limitations (current Photon API):
- Attachments are metadata only — no download URL yet
- Outbound attachment send not wired (sidecar can add easily)
- Reactions / message effects not exposed yet

Docs: website/docs/user-guide/messaging/photon.md + sidebar entry.
2026-06-08 13:38:30 -07:00

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Markdown

# Photon iMessage platform plugin
This plugin connects Hermes Agent to iMessage (and WhatsApp Business +
future Spectrum interfaces) through [Photon][photon] — a managed
service that handles the iMessage line allocation, delivery, and
abuse-prevention layer so users don't have to run their own Mac
relay.
The free tier uses Photon's shared iMessage line pool (`type: shared`)
and is the path we recommend for everyone who doesn't already pay for a
dedicated number.
## Architecture
```
┌─────────────────────────┐ HMAC-signed POSTs ┌──────────────────┐
│ Photon Spectrum cloud │ ──────────────────────► │ Hermes Agent │
│ (iMessage line owner) │ │ (Python) │
└─────────────────────────┘ JSON over loopback │ │
▲ ◄────────────────────── │ PhotonAdapter │
│ │ + aiohttp recv │
│ spectrum-ts │ │
│ SDK (Node) │ spawns + super- │
▼ │ vises ▼ │
┌─────────────────────────┐ ├──────────────────┤
│ Node sidecar │ ◄──── X-Hermes- ─ │ Node sidecar │
│ (plugins/.../sidecar) │ Sidecar-Token │ child process │
└─────────────────────────┘ └──────────────────┘
```
Inbound traffic is webhook-only — Hermes runs an aiohttp listener
that verifies `X-Spectrum-Signature` and dedupes on `message.id`.
Outbound traffic goes through a tiny Node sidecar that runs the
`spectrum-ts` SDK. Photon does not currently expose an HTTP
send-message endpoint; their own docs say:
> Pass `space.id` to `Space.send(...)` from a separate `spectrum-ts`
> SDK instance to reply. **No public HTTP send endpoint exists today.**
> — https://photon.codes/docs/webhooks/events
When Photon ships an HTTP send endpoint, `_sidecar_send` is the one
function that swaps and the sidecar disappears. The rest of the
plugin stays the same.
## First-time setup
```bash
# 1. Log in via the device-code flow (opens browser)
hermes photon login
# 2. Full setup: project, user, sidecar deps
hermes photon setup --phone +15551234567
# 3. Expose your webhook URL to the public internet
# (cloudflared, ngrok, your gateway's public hostname, etc.)
# Then register it with Photon:
hermes photon webhook register https://your-host.example.com/photon/webhook
# 4. Save the signing secret it prints to ~/.hermes/.env
# as PHOTON_WEBHOOK_SECRET=...
# Photon only returns it ONCE.
# 5. Start the gateway
hermes gateway start --platform photon
```
## Credentials
Stored in `~/.hermes/auth.json` under `credential_pool`:
```jsonc
{
"credential_pool": {
"photon": [
{ "access_token": "<dashboard-bearer>", "issued_at": ... }
],
"photon_project": [
{ "project_id": "...", "project_secret": "...", "name": "Hermes Agent" }
]
}
}
```
The per-URL webhook signing secret is treated like an API key and
lives in `~/.hermes/.env` as `PHOTON_WEBHOOK_SECRET`.
## Configuration knobs
All env vars are documented in `plugin.yaml`. The most important are:
| Env var | Default | Meaning |
|--------------------------|--------------------|-----------------------------------------|
| `PHOTON_PROJECT_ID` | from auth.json | Spectrum project ID |
| `PHOTON_PROJECT_SECRET` | from auth.json | Spectrum project secret (HTTP Basic) |
| `PHOTON_WEBHOOK_SECRET` | (unset) | Signing secret returned at register |
| `PHOTON_WEBHOOK_PORT` | 8788 | Local port for the aiohttp listener |
| `PHOTON_WEBHOOK_PATH` | /photon/webhook | Path under which the listener mounts |
| `PHOTON_SIDECAR_PORT` | 8789 | Loopback port for sidecar control |
| `PHOTON_HOME_CHANNEL` | (unset) | Default space ID for cron delivery |
| `PHOTON_ALLOWED_USERS` | (unset) | Comma-separated E.164 allowlist |
## Limitations (current Photon API)
- **Attachments are metadata only.** Inbound webhooks include the
filename + MIME type but no download URL. The plugin surfaces a
text marker (`[Photon attachment received: …]`) so the agent knows
something arrived, but cannot read the bytes. Photon's docs note
an attachment retrieval endpoint is on the roadmap.
- **Outbound attachments are not supported yet.** Adding them is
straightforward once the sidecar wires up `attachment(...)` /
`space.send(attachment(...))` from `spectrum-ts`.
- **Reactions, message effects, polls** — not exposed yet; the
`spectrum-ts` SDK supports them, and the sidecar is the natural
place to add them when the agent has reason to use them.
[photon]: https://photon.codes/