# Skill: agent_tool_execution

## Trigger Conditions

Any change involving Gemma-4-E2B agent tools, Exa search, Supabase RAG RPC, or MedGemma escalation.

## Rules

### 1. Tool catalog is authoritative

- Only use: `exa_search`, `supabase_query`, `escalate_medgemma`.
- Never invent tool names in prompts or handlers.
- Bump `TOOL_CATALOG_VERSION` on breaking schema changes.

### 2. Secrets and egress

- `EXA_API_KEY`, `SUPABASE_SERVICE_ROLE_KEY`, MedGemma keys: **backend only**.
- Browser calls BFF routes; never `https://api.exa.ai` directly from the client.
- PHI-scrub queries before any network egress ([`secrets_and_phi_safety`](../secrets_and_phi_safety/SKILL.md)).

### 3. Exa defaults (Pattern 1 — raw retrieval)

```json
{
  "type": "auto",
  "numResults": 10,
  "contents": { "highlights": true }
}
```

- Canonical reference: https://docs.exa.ai/reference/search-api-guide-for-coding-agents
- Do not use deprecated params (`useAutoprompt`, top-level `highlights`, `livecrawl: "always"`).
- `outputSchema` synthesis is BFF-only enrichment; not the default agent-loop path.

### 4. Retrieval policy (NFR-18)

- `supabase_query` first for in-corpus MOH guideline grounding.
- `exa_search` for external/recency queries.
- Final clinical answers must cite chunk IDs (Supabase) or URLs (Exa).

### 5. MedGemma escalation

- Requires consent + audit (NFR-16a) before `escalate_medgemma`.
- No direct Modal URLs from the browser.

### 6. MediaPipe agent output

- Parse tool calls from the **answer channel** when CoT is enabled.
- One block per turn: `<tool_call>` OR `<final>`.

## Package location

[`ml/implementation/nlp/agent_runtime/`](../ml/implementation/nlp/agent_runtime/)