manual_slop/mcp_client.py

# mcp_client.py

#MCP-style file context tools for manual_slop.

# Exposes read-only filesystem tools the AI can call to selectively fetch file
# content on demand, instead of having everything inlined into the context block.
# All access is restricted to paths that are either:
#  - Explicitly listed in the project's allowed_paths set, OR
#  - Contained within an allowed base_dir (must resolve to a subpath of it)

# Tools exposed:
#   read_file(path)              - return full UTF-8 content of a file
#   list_directory(path)         - list entries in a directory (names + type)
#   search_files(path, pattern)  - glob pattern search within an allowed dir
#   get_file_summary(path)       - return the summarize.py heuristic summary
#

from pathlib import Path
import summarize

# ------------------------------------------------------------------ state

# Set by configure() before the AI send loop starts.
# allowed_paths : set of resolved absolute Path objects (files or dirs)
# base_dirs     : set of resolved absolute Path dirs that act as roots
_allowed_paths: set[Path] = set()
_base_dirs: set[Path] = set()


def configure(file_items: list[dict], extra_base_dirs: list[str] | None = None):
    """
    Build the allowlist from aggregate file_items.
    Called by ai_client before each send so the list reflects the current project.

    file_items   : list of dicts from aggregate.build_file_items()
    extra_base_dirs : additional directory roots to allow traversal of
    """
    global _allowed_paths, _base_dirs
    _allowed_paths = set()
    _base_dirs = set()

    for item in file_items:
        p = item.get("path")
        if p is not None:
            rp = Path(p).resolve()
            _allowed_paths.add(rp)
            _base_dirs.add(rp.parent)

    if extra_base_dirs:
        for d in extra_base_dirs:
            dp = Path(d).resolve()
            if dp.is_dir():
                _base_dirs.add(dp)


def _is_allowed(path: Path) -> bool:
    """
    Return True if `path` is within the allowlist.
    A path is allowed if:
      - it is explicitly in _allowed_paths, OR
      - it is contained within (or equal to) one of the _base_dirs
    """
    rp = path.resolve()
    if rp in _allowed_paths:
        return True
    for bd in _base_dirs:
        try:
            rp.relative_to(bd)
            return True
        except ValueError:
            continue
    return False


def _resolve_and_check(raw_path: str) -> tuple[Path | None, str]:
    """
    Resolve raw_path and verify it passes the allowlist check.
    Returns (resolved_path, error_string).  error_string is empty on success.
    """
    try:
        p = Path(raw_path).resolve()
    except Exception as e:
        return None, f"ERROR: invalid path '{raw_path}': {e}"
    if not _is_allowed(p):
        return None, (
            f"ACCESS DENIED: '{raw_path}' is not within the allowed paths. "
            f"Use list_directory or search_files on an allowed base directory first."
        )
    return p, ""


# ------------------------------------------------------------------ tool implementations

def read_file(path: str) -> str:
    """Return the UTF-8 content of a file, or an error string."""
    p, err = _resolve_and_check(path)
    if err:
        return err
    if not p.exists():
        return f"ERROR: file not found: {path}"
    if not p.is_file():
        return f"ERROR: not a file: {path}"
    try:
        return p.read_text(encoding="utf-8")
    except Exception as e:
        return f"ERROR reading '{path}': {e}"


def list_directory(path: str) -> str:
    """List entries in a directory. Returns a compact text table."""
    p, err = _resolve_and_check(path)
    if err:
        return err
    if not p.exists():
        return f"ERROR: path not found: {path}"
    if not p.is_dir():
        return f"ERROR: not a directory: {path}"
    try:
        entries = sorted(p.iterdir(), key=lambda e: (e.is_file(), e.name.lower()))
        lines = [f"Directory: {p}", ""]
        for entry in entries:
            kind = "file" if entry.is_file() else "dir "
            size = f"{entry.stat().st_size:>10,} bytes" if entry.is_file() else ""
            lines.append(f"  [{kind}]  {entry.name:<40}  {size}")
        lines.append(f"  ({len(entries)} entries)")
        return "\n".join(lines)
    except Exception as e:
        return f"ERROR listing '{path}': {e}"


def search_files(path: str, pattern: str) -> str:
    """
    Search for files matching a glob pattern within path.
    pattern examples: '*.py', '**/*.toml', 'src/**/*.rs'
    """
    p, err = _resolve_and_check(path)
    if err:
        return err
    if not p.is_dir():
        return f"ERROR: not a directory: {path}"
    try:
        matches = sorted(p.glob(pattern))
        if not matches:
            return f"No files matched '{pattern}' in {path}"
        lines = [f"Search '{pattern}' in {p}:", ""]
        for m in matches:
            rel = m.relative_to(p)
            kind = "file" if m.is_file() else "dir "
            lines.append(f"  [{kind}]  {rel}")
        lines.append(f"  ({len(matches)} match(es))")
        return "\n".join(lines)
    except Exception as e:
        return f"ERROR searching '{path}': {e}"


def get_file_summary(path: str) -> str:
    """
    Return the heuristic summary for a file (same as the initial context block).
    For .py files: imports, classes, methods, functions, constants.
    For .toml: table keys. For .md: headings. Others: line count + preview.
    """
    p, err = _resolve_and_check(path)
    if err:
        return err
    if not p.exists():
        return f"ERROR: file not found: {path}"
    if not p.is_file():
        return f"ERROR: not a file: {path}"
    try:
        content = p.read_text(encoding="utf-8")
        return summarize.summarise_file(p, content)
    except Exception as e:
        return f"ERROR summarising '{path}': {e}"


# ------------------------------------------------------------------ tool dispatch

TOOL_NAMES = {"read_file", "list_directory", "search_files", "get_file_summary"}


def dispatch(tool_name: str, tool_input: dict) -> str:
    """
    Dispatch an MCP tool call by name.  Returns the result as a string.
    """
    if tool_name == "read_file":
        return read_file(tool_input.get("path", ""))
    if tool_name == "list_directory":
        return list_directory(tool_input.get("path", ""))
    if tool_name == "search_files":
        return search_files(tool_input.get("path", ""), tool_input.get("pattern", "*"))
    if tool_name == "get_file_summary":
        return get_file_summary(tool_input.get("path", ""))
    return f"ERROR: unknown MCP tool '{tool_name}'"


# ------------------------------------------------------------------ tool schema helpers
# These are imported by ai_client.py to build provider-specific declarations.

MCP_TOOL_SPECS = [
    {
        "name": "read_file",
        "description": (
            "Read the full UTF-8 content of a file within the allowed project paths. "
            "Use get_file_summary first to decide whether you need the full content."
        ),
        "parameters": {
            "type": "object",
            "properties": {
                "path": {
                    "type": "string",
                    "description": "Absolute or relative path to the file to read.",
                }
            },
            "required": ["path"],
        },
    },
    {
        "name": "list_directory",
        "description": (
            "List files and subdirectories within an allowed directory. "
            "Shows name, type (file/dir), and size. Use this to explore the project structure."
        ),
        "parameters": {
            "type": "object",
            "properties": {
                "path": {
                    "type": "string",
                    "description": "Absolute path to the directory to list.",
                }
            },
            "required": ["path"],
        },
    },
    {
        "name": "search_files",
        "description": (
            "Search for files matching a glob pattern within an allowed directory. "
            "Supports recursive patterns like '**/*.py'. "
            "Use this to find files by extension or name pattern."
        ),
        "parameters": {
            "type": "object",
            "properties": {
                "path": {
                    "type": "string",
                    "description": "Absolute path to the directory to search within.",
                },
                "pattern": {
                    "type": "string",
                    "description": "Glob pattern, e.g. '*.py', '**/*.toml', 'src/**/*.rs'.",
                },
            },
            "required": ["path", "pattern"],
        },
    },
    {
        "name": "get_file_summary",
        "description": (
            "Get a compact heuristic summary of a file without reading its full content. "
            "For Python: imports, classes, methods, functions, constants. "
            "For TOML: table keys. For Markdown: headings. Others: line count + preview. "
            "Use this before read_file to decide if you need the full content."
        ),
        "parameters": {
            "type": "object",
            "properties": {
                "path": {
                    "type": "string",
                    "description": "Absolute or relative path to the file to summarise.",
                }
            },
            "required": ["path"],
        },
    },
]