---
issue: 10
title: Latest session retrieval — extend core/session.py
status: done
failure_log: null
tags:
  - type/story
  - status/done
---

## Implementation

Extend `src/mantle/core/session.py` with a function to retrieve the latest session log, optionally filtered by author. This provides the data layer for the resume briefing — the compiler (story 2) will call this function to include the latest session in the compiled context.

### src/mantle/core/session.py (modify)

#### New function

- `latest_session(project_dir: Path, *, author: str | None = None) -> tuple[SessionNote, str] | None` — Return the most recent session log as a `(frontmatter, body)` tuple. Uses `list_sessions()` to get sorted paths (oldest-first), then reads the last one via `load_session()`. If `author` is provided, passes it to `list_sessions()` for filtering. Returns `None` if no matching sessions exist.

#### Design decisions

- **Builds on existing functions.** `list_sessions()` already handles directory scanning, sorting, and author filtering. `load_session()` already handles reading and parsing. This function composes them into a single convenience call.
- **Returns None, not raises.** A project with no session logs is a valid state (new project, first session). The caller (compiler) uses `{% if %}` guards in the template for this case.
- **Author parameter optional.** Calling without `author` returns the overall latest session. Calling with `author` returns the latest for that user. The compiler will pass `git config user.email` to filter to the current user.

## Tests

### tests/core/test_session.py (modify)

Add new tests alongside existing session tests. Use the same fixture pattern — `tmp_path` with `.mantle/sessions/` and `state.md`.

- **latest_session**: returns None when no sessions exist
- **latest_session**: returns the most recent session after saving multiple
- **latest_session**: returns (SessionNote, str) tuple with correct frontmatter and body
- **latest_session**: filters by author when specified
- **latest_session**: returns None when author has no sessions
- **latest_session**: returns latest for specified author when multiple authors exist
