feat: add Agent Zero OpenRouter integration to litellm-api-keys

- Added Agent Zero (kagentz .14) to .env fallback inventory
- Documented direct OpenRouter API access (not via LiteLLM proxy)
- Included key prefix, user ID, model config, and rotation procedure
- Cross-referenced with agent-zero-openrouter-key.prose.md

litellm-api-keys.prose.md

@@ -257,9 +257,51 @@ reads use per-agent identities. This eliminates the single shared token risk.
 | Agent | .env Keys |
 |-------|-----------|
 | Mumuni | MUMUNI_LITELLM_API_KEY, MUMUNI_ZULIP_API_KEY |
-| Tanko | TANKO_LITELLM_API_KEY, TANKO_ZULIP_API_KEY |
-| Koby | (wrapper injects from vault — .env has Telegram token) |
-| Koonimo | KOONIMO_LITELLM_API_KEY, KOONIMO_ZULIP_API_KEY |
+|| Tanko | TANKO_LITELLM_API_KEY, TANKO_ZULIP_API_KEY |
+|| Koby | (wrapper injects from vault — .env has Telegram token) |
+|| Koonimo | KOONIMO_LITELLM_API_KEY, KOONIMO_ZULIP_API_KEY |
+|| Agent Zero (kagentz .14) | OPENROUTER_API_KEY (direct OpenRouter access) |
+
+### Agent Zero (kagentz .14) — OpenRouter Integration (2026-09-01)
+
+Agent Zero runs in Docker on kagentz (CT105) and uses **direct OpenRouter API access**,
+not via the LiteLLM proxy. This is because Agent Zero's workflow (self-update manager,
+UI bootstrap, model selection) is built around OpenRouter's native authentication.
+
+**Key Storage:**
+- **Container**: `/a0/usr/.env` (line ~72: `API_KEY_OPENROUTER=sk-or-v1-…`)
+- **Vault**: Infisical secret `OPENROUTER_API_KEY` (project=agents, env=production)
+- **Fallback**: The container's .env is the primary source; vault sync is optional
+  (unlike fleet agents which require vault injection)
+
+**Current Key (2026-09-01):**
+- **Prefix**: `sk-or-v1-0af3f3…`
+- **User**: `user_2rt9lCqcd5d7Vk1t18DHsvWdPTT`
+- **Plan**: Paid (not free tier)
+- **Usage**: 0 (as of 2026-09-01)
+
+**Model Configuration:**
+- **Preset**: "Cost Efficient" (`/a0/usr/plugins/_model_config/presets.yaml`)
+- **Model**: `openrouter/moonshotai/kimi-k3`
+- **API Base**: (empty — uses OpenRouter default)
+
+**Why not LiteLLM proxy?**
+Agent Zero's architecture was designed before the fleet adopted the LiteLLM proxy
+standard. The container runs `/exe/self_update_manager.py` and `/a0/run_ui.py` which
+directly call OpenRouter via Python's requests library. Converting would require:
+1. Refactoring all LLM calls to use `litellm` library
+2. Adding vault wrapper injection
+3. Updating self_update_manager to use proxy-aware key handling
+
+**Rotation Procedure:**
+1. Generate new key in OpenRouter UI
+2. Update container: `sed -i 's/^API_KEY_OPENROUTER=.*/API_KEY_OPENROUTER=<new_key>/' /a0/usr/.env`
+3. Update vault: `infisical secrets set OPENROUTER_API_KEY=<new_key> --projectId=agents --env=production`
+4. Restart container: `sudo docker exec agent-zero supervisorctl restart run_ui`
+5. Verify: `curl -s https://openrouter.ai/api/v1/auth/key -H "Authorization: Bearer <new_key>"`
+
+**Related Contract:**
+- `agent-zero-openrouter-key.prose.md` — Full agent-zero key management contract
 
 ## Key Rotation Log