---
name: omp-search-provider-fallback-debug
description: "Diagnose why the omp harness web_search silently uses a fallback provider (e.g. Kagi) instead of the configured primary (SearXNG): the fallbackChains masking pattern, the searxng.endpoint base-URL scheme/guard-chain trap, and the cli.js + content-type probes that prove it."
---

# omp web_search silently using the wrong provider

Symptom: agent searches return results from a fallback provider (e.g. **Kagi**) even though
`modelRoles.web` is set to the intended primary (e.g. `web/searxng`). The primary errors
every time and the failure is invisible because a fallback answers successfully.

## The masking mechanism (always check this first)

`~/.omp/agent/config.yml`:
- `modelRoles.web:` is the primary (e.g. `web/searxng`).
- `retry.fallbackChains.web:` is an ordered list tried when the primary throws. The FIRST
  entry silently serves whenever the primary errors. In this fleet it is `web/kagi`, so any
  SearXNG error == Kagi answers and you never see an error.

So "searches go through Kagi" almost always means "SearXNG is failing", not a routing mistake.

## The SearXNG endpoint trap (the usual root cause here)

`searxng.endpoint` in config.yml must be a **full base URL pointing at the direct JSON port**,
used **verbatim** by omp (no scheme auto-added, no normalize — confirmed in `cli.js`). Two ways
it breaks:

1. **Bare host** (e.g. `search.franksdank.cloud`, no scheme): omp does `new URL(\`${endpoint}/search\`)`
   → **throws** immediately (URL needs a scheme). SearXNG never contacted.
2. **The guarded vhost** (`https://search.franksdank.cloud`): returns Anubis' **"Making sure
   you're not a bot!"** challenge page at HTTP **200 `text/html`**. omp calls `o.json()`
   unconditionally regardless of content-type → throws on the leading `<`. There is
   deliberately NO API path through the guard chain (JS challenge + UA denylist).

**Correct value** (direct published port, http scheme preserved — reachable from the LAN only):

```yaml
searxng:
  endpoint: http://192.168.0.143:8081   # Dankclaw; NOT the vhost, NOT schemeless
```

The published port source (192.168.x/loopback/LAN) is in SearXNG's `pass_ip`, so it bypasses
the JSON rate limiter (hardcoded `API_MAX=4`/IP/hr, not settable except via `pass_ip`).

## Prove it (don't guess)

1. Content-type probe, both paths — the decisive check:
   ```
   curl -sk -o /tmp/vh -w "vhost ct=%{content_type}\n" "https://search.franksdank.cloud/search?q=test&format=json"   # expect text/html (Anubis)
   curl -s  -o /tmp/dp -w "direct ct=%{content_type}\n" "http://192.168.0.143:8081/search?q=test&format=json"          # expect application/json
   ```
   vhost = `text/html` + direct = `application/json` confirms the trap.
2. Code path, in the installed omp dist (NOT a worktree):
   `/home/blank/.bun/install/global/node_modules/@oh-my-pi/pi-coding-agent/dist/cli.js`
   (find install: `dirname $(readlink -f $(which omp))`). Grep the SearXNG provider:
   - `searxng.endpoint` config def → description "Base URL of a self-hosted SearXNG instance".
   - the request builder `...=e.replace(/\/+$/,""),new URL(\`${r}/search\`)...` → endpoint is
     verbatim, scheme NOT added.
   - `X2c`/`J2c` → `if(!o.ok)throw` then `return await o.json()` → HTML 200 passes `.ok` and
     blows up in `.json()`.

## Apply + verify

- Fix is a harness config edit (`cfg://searxng/endpoint` prompts the user, or edit config.yml).
  Confirm with the user first — it is their live harness config.
- Verification after applying: fire a real `web_search` and confirm it returns
  `provider:"searxng"` (not `"searxng"`-then-fallback / not `"kagi"`).

## Related gotcha (same masking, different cause)

If SearXNG answers JSON but returns empty `results` with `unresponsive_engines` (VPN-exit-IP
CAPTCHA/429 on google/brave), omp's `vcs` throws a 503 → Kagi again. That's an engine-health
problem, fix in `[[SearXNG]]`/`[[SearXNG Providers]]`, not the endpoint.

## Hardening option

Drop or reorder `web/kagi` / `web/perplexity` in `retry.fallbackChains.web` so primary failures
surface instead of silently spending a paid Kagi credit. Flag to user before editing.