## Implementation Plan: Add URL Format Validation to SEO Diagnostics Job Queue

### 1. Modify `devplacepy/models.py`

**Current (committed) code in `SeoRunForm.url_scheme` validator (lines ~456–462):**

```python
@field_validator("url")
@classmethod
def url_scheme(cls, value):
    text = value.strip()
    if not text:
        raise ValueError("A URL is required")
    return text       # ← No scheme validation
```

**Changes to apply:**

1. Add import at top of file (preferably near existing imports):
   ```python
   from urllib.parse import urlparse
   ```

2. Replace the validator body with:
   ```python
   @field_validator("url")
   @classmethod
   def url_scheme(cls, value):
       text = value.strip()
       if not text:
           raise ValueError("A URL is required")
       scheme = urlparse(text).scheme
       if scheme not in ("http", "https"):
           raise ValueError("URL must start with http:// or https://")
       return text
   ```

**Rationale:** `urlparse` extracts the scheme correctly for all edge cases:
| Input | `.scheme` | Valid? |
|---|---|---|
| `"ahttps://devplace.net/sitem"` | `"ahttps"` | No → rejected |
| `"/feed"` | `""` | No → rejected |
| `"https://example.com"` | `"https"` | Yes |
| `"http://example.com"` | `"http"` | Yes |
| `"   "` | — | Rejected by empty‑string check first |

This catches both malformed schemes (`ahttps://…`) and relative paths (`/feed`) that would otherwise become malformed after `_normalize_url`.

### 2. Add Tests in `tests/api/tools/seo.py`

Add two new test functions **after** the existing tests, following the same `try/finally`/`_clear_seo_jobs()` pattern.

**Test 1 – `test_run_rejects_malformed_scheme`:**
- POST to `/tools/seo/run` with `{"url": "ahttps://devplace.net/sitem", "mode": "url"}`
- Expect HTTP 400 or 422 status code

**Test 2 – `test_run_rejects_relative_path`:**
- POST to `/tools/seo/run` with `{"url": "/feed", "mode": "url"}`
- Expect HTTP 400 or 422 status code

### 3. Environment Fix for Verification Commands

Earlier attempts failed because of PEP 668 (`pip install` blocked in system environment). To ensure the verification commands run, the agent **must** use one of these two approaches **before** running `pip install -e '.[dev]' -q`:

- **Option A (preferred):** Create and activate a virtual environment:
  ```bash
  python -m venv .venv
  source .venv/bin/activate
  ```

- **Option B (fallback):** Prepend `PIP_REQUIRE_VIRTUALENV=false` or pass `--break-system-packages`:
  ```bash
  PIP_REQUIRE_VIRTUALENV=false pip install -e '.[dev]' -q
  ```
  or
  ```bash
  pip install --break-system-packages -e '.[dev]' -q
  ```

Then run:
```bash
make test-unit
pip install -q ruff && ruff check .
```

---

## Definition of Done

- [ ] The `url_scheme` validator in `SeoRunForm` rejects `"ahttps://devplace.net/sitem"` with a `ValidationError`.
- [ ] The validator rejects `"/feed"` with a `ValidationError`.
- [ ] The validator accepts `"https://example.com"` and `"http://example.com"`.
- [ ] Two new test functions exist in `tests/api/tools/seo.py` that verify the two rejection cases above.
- [ ] `make test-unit` passes (all tests, including the two new ones, succeed).
- [ ] `ruff check .` passes with no new linting errors.
- [ ] No existing tests are broken or modified (only additive changes).
- [ ] The environment is set up so that `pip install` does not fail due to PEP 668 (virtual env or `--break-system-packages`).