# 2026-07-08 — Hermes resident agent

**Status:** Planned

## Goal

Turn Hermes from a keyword router into a resident LLM-backed agent: a
long-running service you converse with, which reasons over the full 28-tool
MCP surface, holds session context, and is surfaced as the **main entry point
of the control-room web UI** ([companion plan](2026-07-08-control-room-webui.md)).
Oikos already has the agentic substrate — policy classes, approval gating,
`agent_activity`, an OODA loop; this gives it the conversational front half.

## What exists vs what's added

Today `cmd/hermes/main.go` contains no LLM anywhere: `routeQuery` is
`strings.Contains` over ~6 phrases, `extractEntity` knows 5 hardcoded
services, and everything else silently falls back to `get_health_summary`.
But the hard plumbing already exists and is reused as-is:

- `mcpClient` (main.go:190) — working Streamable-HTTP MCP client
  (initialize → session → `tools/call` with SSE frame parsing).
- `listTools()` (main.go:318) — currently dead code; extended (below) it
  becomes the bridge that feeds MCP tool schemas to Claude.
- `.agents/HERMES.md` / `hermes/SOUL.md` — the persona, becomes the system
  prompt.
- `agent_activity` hypertable + `correlation_id` conventions — where tool
  calls get logged so the control room can show the agent working.

## Architecture decision: hand-rolled tool loop, not the MCP connector

Two ways to let Claude drive the tools:

1. **Anthropic MCP connector** (`mcp_servers` param on the Messages API):
   zero loop code, but Anthropic's servers must reach the MCP endpoint over
   the public internet. `mcp.hubris.network` is currently exposed *without
   auth* — a hole the [gaps plan](2026-07-08-oikos-gaps-and-improvements.md)
   says to close, not to build on. Keeping the MCP surface mesh-private is
   the right posture for a homelab control plane.
2. **Hand-rolled agent loop** (~200 lines): Hermes calls the Messages API
   with tool definitions translated from `tools/list`, executes Claude's
   tool_use blocks through its *existing* `mcpClient` inside the mesh, feeds
   back `tool_result` blocks, repeats until Claude answers in text.

**Decision: (2).** MCP tool `inputSchema` is already JSON Schema — the exact
format the Anthropic `tools` parameter expects — so translation is a field
rename. Only the conversation text ever leaves the mesh; the tool transport
stays private. Use the official `anthropic-sdk-go`.

## Design

### Agent loop (`cmd/hermes/agent.go`, new)

```
system prompt  = SOUL.md content (mounted; already provisioned by tools/setup-hermes-soul.sh)
tools          = listToolsFull()   // extend listTools() to return name, description, inputSchema
loop (max 15 iterations):
  resp = messages.New(model, system, history, tools)
  if resp has tool_use blocks:
      for each: result = mcpClient.callTool(name, args)   // existing code path
                log to agent_activity (correlation_id = session turn id)
      append assistant msg + tool_result user msg to history
  else: final text → stream to caller, persist turn
```

- Model: `claude-sonnet-5` default, `HERMES_MODEL` override. `max_tokens`
  and iteration cap configurable; hard per-turn budget so a pathological
  loop can't burn the API bill.
- `ANTHROPIC_API_KEY` from env / Infisical (same secret path as other creds).
- Mutations need no new guardrails: the agent's only write path is
  `request_execution`, which flows through the existing risk-class /
  approval machinery. The agent's actor identity is `agent:hermes`.
  **Depends on gaps-plan bug A1** (approvals FK) — without that fix the
  agent's config mutations dead-end silently, which is worse when a
  conversational agent confidently reports "queued for approval".

### HTTP surface (`cmd/hermes/main.go`)

- `POST /chat` `{session_id?, message}` → **SSE stream** of typed events:
  `text` (deltas), `tool_use` (name + args), `tool_result` (truncated),
  `done` (session_id, usage). The web UI renders tool calls as inline chips
  as they happen.
- `GET /sessions`, `GET /sessions/{id}` — history for the UI.
- `/query` kept for scripts/structured callers. The toy NLU is **removed**
  (per gaps plan §C): a `query` with no `tool` returns "natural language
  belongs to /chat" plus the tool list from the now-live `listTools()`.
- `/healthz` unchanged.

### Sessions (Postgres, new migration)

`agent_sessions (id, title, actor, created_at, last_active_at)` and
`agent_messages (id, session_id, role, content JSONB, created_at)` in the
shared oikos DB — Hermes gains a `DATABASE_URL` (it's in the same compose
stack). DB-backed rather than in-memory so conversations survive restarts
and the control room can list/replay them. Tool invocations additionally go
to `agent_activity` with the session's correlation_id, so the existing
agent-activity page and the ops ledger join up with zero new query paths.

### Connectivity & auth

- Compose: hermes already runs under the `full` profile; add
  `ANTHROPIC_API_KEY`, `DATABASE_URL` env.
- Caddy: route `oikos.hubris.network/agent/*` → `hermes:8092` **behind the
  same Authentik forward_auth** as the rest of the vhost, stripping the
  `/agent` prefix. The web UI then calls same-origin `/agent/chat` — no
  CORS, and EventSource/fetch-streaming work unmodified.
- Hermes enforces trusted-proxy headers (`X-Authentik-Username`) when
  `HERMES_TRUSTED_PROXY=true`, and finally implements the `mesh_only: true`
  check that `hermes/config.yaml:9` promises but `main.go` never enforces
  (gaps plan B3). Direct :8092 access stays mesh-only for agents/scripts.

### Web UI entry point (amends the control-room plan)

The agent chat becomes the **home view** of the control room (`/ui/#/`):

- Center: conversation pane (streamed text, expandable tool-call chips
  showing args/results, correlation-id links into the ops ledger).
- Right rail: live context — pending approvals with approve/deny buttons,
  recent events, health strip. When the agent's `request_execution` needs
  approval, the approval card appears in the rail *mid-conversation* (via
  the `approval.created` SSE event) and can be decided without leaving chat.
  That's the whole product in one screen: ask → watch it act → approve →
  watch it complete.
- A persistent chat drawer is available from every other page.
- Session list in the nav; sessions resumable.

### Later (explicitly out of scope for v1)

- Matrix bridge: Hermes as a Matrix bot in the operator room, reusing the
  notifier's homeserver credentials — same `/chat` loop, different frontend.
- Proactive mode: agent opens a session itself when a signal fires
  (escalation-with-context instead of a bare alert).

## Milestones

- **H1 — loop:** `agent.go` + anthropic-sdk-go; `listToolsFull()`; `/chat`
  (non-streaming JSON first); remove toy NLU, fix `/query` fallback + help.
  Verify by curl: multi-tool question ("what's degraded and what depends on
  it?") produces chained `get_health_summary` → `get_blast_radius` calls.
- **H2 — state + streaming:** sessions migration, DB persistence, SSE
  streaming on `/chat`, `agent_activity` logging, budgets.
- **H3 — UI entry point:** home chat view + context rail + drawer in the
  control-room SPA (needs control-room M1; rail approvals need M2's
  `approval.created` event and gaps-plan A1).
- **H4 (optional):** Matrix bridge, proactive sessions.

## Files

```
cmd/hermes/agent.go            # Claude loop (new)
cmd/hermes/main.go             # /chat, /sessions, NLU removal, mesh/proxy auth
cmd/hermes/store.go            # session persistence (new)
migrations/0xx_agent_sessions.up.sql
hermes/config.yaml             # model, budgets; drop query_routing block
compose/ (env), Caddyfile.oikos (/agent route)
web/src/pages/Chat.svelte + lib/stores/chat.ts   # control-room home view
go.mod                         # anthropic-sdk-go
```

## Verification

- H1: `curl -N /agent/chat` with a question requiring 2+ tools; confirm the
  tool chain in the response and rows in `agent_activity`.
- H2: restart hermes mid-session, resume by session_id, history intact.
- H3: from the UI home, ask Hermes to restart a low-risk service; watch the
  tool chips stream, the execution appear in the rail, and (for a gated
  action) the approval card arrive and be decidable in place.