# Tier 4: The Utility Agents (Compiler / QA)

**Designated Models:** DeepSeek V3 (Lowest cost possible).
**Execution Frequency:** On-demand (Intercepts local failures).
**Core Role:** Single-shot, stateless translation of machine garbage into human English.

Tier 4 acts as the financial firewall. It solves the expensive problem of feeding massive (e.g., 3,000-token) stack traces back into a mid-tier LLM's context window. Tier 4 agents wake up, translate errors, and immediately die.

## Memory Context & Paths

### Path A: The Stack Trace Interceptor (Translator)
*   **Trigger:** A Tier 3 Contributor executes a script, resulting in a non-zero exit code with a massive `stderr` payload.
*   **What it Sees (Context):**
    *   **Raw Error Output:** The exact traceback from the runtime/compiler.
    *   **Offending Snippet:** *Only* the specific function or 20-line block of code where the error originated.
*   **What it Ignores:** Everything else. It is blind to the "Why" and focuses only on "What broke."
*   **Output Format:** A surgical, highly compressed string (20-50 tokens) passed back into the Tier 3 Contributor's working memory (e.g., "Syntax Error on line 42: You missed a closing parenthesis. Add `]`").

### Path B: The Linter / Formatter (Pedant)
*   **Trigger:** Tier 3 believes it finished a Ticket, but pre-commit hooks (e.g., `ruff`, `eslint`) fail.
*   **What it Sees (Context):**
    *   **Linter Warning:** Specific error (e.g., "Line too long", "Missing type hint").
    *   **Target File:** Code written by Tier 3.
*   **What it Ignores:** Business logic. It only cares about styling rules.
*   **Output Format:** A direct `sed` command or silent diff overwrite via tools to fix the formatting without bothering Tier 2 or consuming Tier 3 loops.

### Path C: The Flaky Test Debugger (Isolator)
*   **Trigger:** A localized unit test fails due to logic (e.g., `assert 5 == 4`), not a syntax crash.
*   **What it Sees (Context):**
    *   **Failing Test Function:** The exact `pytest` or `go test` block.
    *   **Target Function:** The specific function being tested.
*   **What it Ignores:** The rest of the test suite and module.
*   **Output Format:** A quick diagnosis sent to Tier 3 (e.g., "The test expects an integer, but your function is currently returning a stringified float. Cast to `int`").