You are a senior code reviewer preparing to review code changes.

## Code Changes

```diff
diff --git a/ftl_project_expert/cli.py b/ftl_project_expert/cli.py
index 445a0dd..27fe03e 100644
--- a/ftl_project_expert/cli.py
+++ b/ftl_project_expert/cli.py
@@ -164,15 +164,42 @@ def _reasons_export():
 # --- CLI ---
 
 
+def _load_env_file(path, silent=False):
+    """Load KEY=VALUE pairs from a file into os.environ (existing vars take precedence)."""
+    try:
+        with open(path, encoding="utf-8") as f:
+            for line in f:
+                line = line.strip()
+                if not line or line.startswith("#"):
+                    continue
+                if "=" not in line:
+                    continue
+                key, _, value = line.partition("=")
+                key = key.strip()
+                if key.startswith("export "):
+                    key = key[7:].strip()
+                value = value.strip()
+                if len(value) >= 2 and value[0] == value[-1] and value[0] in ("'", '"'):
+                    value = value[1:-1]
+                if key and key not in os.environ:
+                    os.environ[key] = value
+    except OSError as e:
+        if not silent:
+            click.echo(f"Warning: could not read env file {path}: {e}", err=True)
+
+
 @click.group()
 @click.version_option(package_name="ftl-project-expert")
 @click.option("--quiet", "-q", is_flag=True, default=False,
               help="Suppress output to stdout")
 @click.option("--model", "-m", default="claude", help="Model to use (default: claude)")
 @click.option("--timeout", "-t", default=300, type=int, help="LLM timeout in seconds")
+@click.option("--env-file", default=".env", help="Path to .env file (default: .env)")
 @click.pass_context
-def cli(ctx, quiet, model, timeout):
+def cli(ctx, quiet, model, timeout, env_file):
     """Build expert knowledge bases from project management data."""
+    is_default = ctx.get_parameter_source("env_file") != click.core.ParameterSource.COMMANDLINE
+    _load_env_file(env_file, silent=is_default)
     ctx.ensure_object(dict)
     ctx.obj["quiet"] = quiet
     ctx.obj["model"] = model

```

## Your Task

Analyze the diff and identify what additional information you need to render confident verdicts.
Do NOT render verdicts yet. Only request observations.

## Available Observation Tools

| Tool | Purpose | When to use |
|------|---------|-------------|
| `exception_hierarchy` | Show exception MRO and subclasses | Retry logic, exception handling |
| `raises_analysis` | What exceptions a function raises | New function calls, error paths |
| `call_graph` | What a function calls | Impact analysis |
| `find_usages` | Where a symbol is used (with prod/test split) | Quick integration lookup |
| `find_callers` | Caller analysis with prod/test split and calling context | Method signature changes, return type changes, constructor modifications, integration verification |
| `test_coverage` | Find tests for a file (uses coverage-map if available) | Test coverage claims |
| `coverage_map_tests` | Find tests covering a file (from coverage-map.json) | Precise test coverage from actual execution |
| `coverage_map_files` | Find files covered by tests matching a pattern | Impact analysis for test changes |
| `function_body` | Full source of a function/method | Need complete function context beyond diff hunks |
| `file_imports` | Extract imports from a file | Verify import changes, check dependencies |
| `project_dependencies` | Get pyproject.toml/requirements.txt | Verify new imports have dependencies |
| `related_test_files` | Find test files for a source file | Discover tests by naming, imports, and coverage map |
| `class_hierarchy` | Show base classes and their `__init__` signatures | Class changes its parent, modifies `__init__`, or uses `super()` |
| `symbol_migration` | Check if a rename is complete across the repo | Symbol renamed in diff — verify old name is fully removed |
| `generator_info` | Report whether a function uses `yield` | Function might be a generator — affects return value semantics |

## What to Look For

1. **Exception handling**: Any `retry_if_exception_type`, `except`, or exception class references
2. **New dependencies**: Calls to external libraries where you don't know the error behavior
3. **Behavioral changes**: Modified logic where you need to verify callers/callees
4. **Test claims**: References to tests you can't see in the diff
5. **Inheritance changes**: Class definition changes, new base classes, `super()` calls
6. **Renames**: Symbols that appear to have been renamed in the diff
7. **Factory methods**: Calls to `@classmethod` / `@staticmethod` constructors (e.g. `Result.error(...)`) — request `function_body` to see their implementation

## Output Format

Output a JSON array of observation requests:

```json
[
  {"name": "descriptive_name", "tool": "tool_name", "params": {"param": "value"}},
  ...
]
```

If you don't need any observations (simple changes, all context is in the diff), output:

```json
[]
```

## Examples

For a diff containing `retry_if_exception_type((OSError, httpx.TransportError))`:
```json
[
  {"name": "oserror_subclasses", "tool": "exception_hierarchy", "params": {"class_name": "builtins.OSError"}},
  {"name": "transport_errors", "tool": "exception_hierarchy", "params": {"class_name": "httpx.TransportError"}}
]
```

For a diff adding a new function that calls `oauth_client.get_access_token()`:
```json
[
  {"name": "oauth_exceptions", "tool": "raises_analysis", "params": {"file_path": "src/auth/oauth.py", "function_name": "get_access_token"}}
]
```

For a diff modifying a method but you need the full function to verify:
```json
[
  {"name": "full_getattr", "tool": "function_body", "params": {"file_path": "src/proxy.py", "function_name": "__getattr__"}}
]
```

For a diff changing a method signature or return type (verify all callers):
```json
[
  {"name": "handle_request_callers", "tool": "find_callers", "params": {"symbol": "handle_request"}}
]
```

For a diff adding new imports (e.g., `import httpx`):
```json
[
  {"name": "file_imports", "tool": "file_imports", "params": {"file_path": "src/client.py"}},
  {"name": "project_deps", "tool": "project_dependencies", "params": {}}
]
```

For a diff calling a factory method like `ModuleResult.error_result(msg)`:
```json
[
  {"name": "error_result_body", "tool": "function_body", "params": {"file_path": "src/models.py", "function_name": "error_result"}}
]
```

For a diff where a class changes its parent class:
```json
[
  {"name": "client_hierarchy", "tool": "class_hierarchy", "params": {"class_name": "MyClient", "file_path": "src/client.py"}}
]
```

For a diff that renames a symbol (e.g., `OldClient` to `NewClient`):
```json
[
  {"name": "client_rename", "tool": "symbol_migration", "params": {"old_name": "OldClient", "new_name": "NewClient"}}
]
```

For a diff modifying a function that might be a generator:
```json
[
  {"name": "process_gen", "tool": "generator_info", "params": {"file_path": "src/pipeline.py", "function_name": "process_items"}}
]
```

Now analyze the diff above and output your observation requests as JSON:
