diff --git a/mcp/server.py b/mcp/server.py
new file mode 100755
index 0000000..5030eac
--- /dev/null
+++ b/mcp/server.py
@@ -0,0 +1,294 @@
+#!/usr/bin/env python3
+
+import re
+import subprocess
+import sys
+from pathlib import Path
+from typing import Optional
+import time
+from datetime import datetime, timezone
+
+from mcp.server.fastmcp import FastMCP
+
+PROJECT_ROOT = Path(__file__).resolve().parent.parent.parent.parent
+assert (PROJECT_ROOT / "tools" / "config.toml").exists(), f"config.toml not found; PROJECT_ROOT={PROJECT_ROOT}"
+
+_ANSI_ESCAPE = re.compile(r"\x1b(?:[@-Z\\-_]|\[[0-?]*[ -/]*[@-~])")
+
+_AUTONOMY_CACHE = {
+    "mtime": None,
+    "text": ""
+}
+
+def _read_autonomy_message() -> str:
+    path = Path.home() / "autonomy_message.txt"
+
+    if not path.exists():
+        return ""
+
+    stat = path.stat()
+
+    if _AUTONOMY_CACHE["mtime"] != stat.st_mtime:
+        _AUTONOMY_CACHE["mtime"] = stat.st_mtime
+        _AUTONOMY_CACHE["text"] = path.read_text()
+
+    return _AUTONOMY_CACHE["text"]
+
+def _build_autonomy_block() -> str:
+    text = _read_autonomy_message().strip()
+    if not text:
+        return ""
+
+    ts = datetime.now(timezone.utc).isoformat()
+
+    return (
+        "=== AUTONOMY MESSAGE BEGIN ===\n"
+        "source: ~/autonomy_message.txt\n"
+        f"timestamp: {ts}\n\n"
+        f"{text}\n\n"
+        "=== AUTONOMY MESSAGE END ===\n\n"
+    )
+
+def _run(args: list[str], timeout: int) -> str:
+    print(f"[nx-decomp-tools] {' '.join(args)}", file=sys.stderr, flush=True)
+
+    result = subprocess.run(
+        args,
+        cwd=PROJECT_ROOT,
+        capture_output=True,
+        text=True,
+        timeout=timeout,
+    )
+
+    tool_output = _ANSI_ESCAPE.sub("", result.stdout + result.stderr)
+
+    autonomy_block = _build_autonomy_block()
+
+    final_output = (
+        f"{autonomy_block}"
+        "=== TOOL OUTPUT BEGIN ===\n"
+        f"{tool_output}\n"
+        "=== TOOL OUTPUT END ===\n"
+    )
+
+    print(
+        f"[nx-decomp-tools] exit {result.returncode}, {len(final_output)} chars",
+        file=sys.stderr,
+        flush=True,
+    )
+
+    return final_output
+
+mcp = FastMCP("nx-decomp-tools")
+
+
+@mcp.tool()
+def check(
+    function: Optional[str] = None,
+    functions: Optional[list[str]] = None,
+    always_diff: bool = False,
+    warnings_as_errors: bool = False,
+    check_mismatch_comments: bool = False,
+    check_placement: bool = False,
+    context_lines: Optional[int] = None,
+    show_source: bool = False,
+) -> str:
+    """
+    Run tools/check to diff assembly for one or more functions, or all functions.
+
+    Args:
+        function: Single mangled or demangled symbol name to check.
+        functions: List of symbol names to check (checked sequentially, output combined).
+        always_diff: Pass --always-diff (show diff even for matching functions).
+        warnings_as_errors: Pass --warnings-as-errors.
+        check_mismatch_comments: Pass --check-mismatch-comments.
+        check_placement: Pass --check-placement (verify functions are in correct objects).
+        context_lines: Number of context lines for the diff (-U N). Single-function only.
+        show_source: Show source alongside assembly (-c). Single-function only.
+    """
+    targets: list[Optional[str]] = list(functions) if functions else [function] if function else [None]
+
+    base_flags = ["--no-pager", "--format=plain"]
+    if always_diff: base_flags.append("--always-diff")
+    if warnings_as_errors: base_flags.append("--warnings-as-errors")
+    if check_mismatch_comments: base_flags.append("--check-mismatch-comments")
+    if check_placement: base_flags.append("--check-placement")
+
+    after_flags = (["-U", str(context_lines)] if context_lines is not None else []) + (["-c"] if show_source else [])
+
+    results = []
+    for target in targets:
+        args = ["tools/check"] + base_flags + ([target] + after_flags if target else [])
+        output = _run(args, timeout=60 if target else 600)
+        if target is None and len(output) > 50_000:
+            output = output[:50_000] + "\n\n[output truncated at 50,000 chars]"
+        results.append(f"=== {target} ===\n{output}" if len(targets) > 1 else output)
+
+    return "\n".join(results)
+
+
+@mcp.tool()
+def check_status(
+    function: Optional[str] = None,
+    functions: Optional[list[str]] = None,
+) -> str:
+    """
+    Check match status for one or more functions without showing the full diff.
+    Returns OK/mismatch status plus diff statistics (matching lines, changed lines,
+    added/deleted lines) so you can gauge how close a function is without the noise.
+
+    Args:
+        function: Single mangled or demangled symbol name to check.
+        functions: List of symbol names to check (results combined).
+    """
+    targets: list[str] = list(functions) if functions else ([function] if function else [])
+    if not targets:
+        return "check_status requires at least one function name"
+
+    # Markers used by asm-differ's plain format:
+    #   (space) = matching
+    #   s       = same opcode, different immediate/offset
+    #   |       = different instruction
+    #   r       = register-renamed
+    #   <       = target-only (deleted from current)
+    #   >       = current-only (added in current)
+    _DIFF_LINE = re.compile(
+        r"^[0-9a-f]+:\s+\S.*?([ s|r<>])\s+(?:[0-9a-f]+:\s+\S.*)?$"
+    )
+
+    results = []
+    for target in targets:
+        raw = _run(
+            ["tools/check", "--no-pager", "--format=plain", "--always-diff", target],
+            timeout=60,
+        )
+
+        if "mismatch" in raw and "OK" not in raw.split("mismatch")[0].split("\n")[-1]:
+            verdict = "mismatch"
+            m = re.search(r"mismatch at [0-9a-fx]+: (.+)", raw)
+            reason = m.group(1).strip() if m else "unknown"
+        else:
+            verdict = "OK"
+            reason = ""
+
+        counts: dict[str, int] = {"match": 0, "s": 0, "|": 0, "r": 0, "<": 0, ">": 0}
+        for line in raw.splitlines():
+            m = _DIFF_LINE.match(line)
+            if m:
+                marker = m.group(1)
+                if marker == " ":
+                    counts["match"] += 1
+                elif marker in counts:
+                    counts[marker] += 1
+
+        total = sum(counts.values())
+        changed = counts["s"] + counts["|"] + counts["r"] + counts["<"] + counts[">"]
+        effectively_matching = counts["match"] + counts["r"]
+
+        if verdict == "OK":
+            summary = f"{target}: OK ({effectively_matching} instructions, {counts['r']} regswap)"
+        else:
+            pct = int(100 * effectively_matching / total) if total > 0 else 0
+            parts = []
+            if counts["|"]: parts.append(f'{counts["|"]} changed')
+            if counts["s"]: parts.append(f'{counts["s"]} imm/offset')
+            if counts["r"]: parts.append(f'{counts["r"]} regswap')
+            if counts["<"]: parts.append(f'{counts["<"]} deleted')
+            if counts[">"]: parts.append(f'{counts[">"]} added')
+            detail = ", ".join(parts) if parts else "no diff lines captured"
+            summary = (
+                f"{target}: mismatch ({reason})\n"
+                f"  {effectively_matching}/{total} lines match ({pct}%), {changed} differ: {detail}"
+            )
+
+        results.append(summary)
+
+    return "\n".join(results)
+
+
+@mcp.tool()
+def listsym(
+    filter: Optional[str] = None,
+    show_undefined: bool = False,
+    show_data: bool = False,
+    show_decompiled: bool = False,
+) -> str:
+    """
+    Run tools/listsym to list symbols.
+
+    Args:
+        filter: Optional search string to filter symbol names.
+        show_undefined: Pass -u (undefined / outgoing refs to unimplemented functions).
+        show_data: Pass -d (include data symbols).
+        show_decompiled: Pass -l (decompiled symbols that exist in the file list).
+    """
+    args = ["tools/listsym"]
+    if show_undefined: args.append("-u")
+    if show_data: args.append("-d")
+    if show_decompiled: args.append("-l")
+    if filter: args.append(filter)
+    return _run(args, timeout=30)
+
+
+@mcp.tool()
+def build(clean: bool = False) -> str:
+    """
+    Run tools/build.py to compile the project.
+
+    Args:
+        clean: Pass --clean to do a clean build.
+    """
+    return _run(["tools/build.py"] + (["--clean"] if clean else []), timeout=300)
+
+
+@mcp.tool()
+def clangd_check(file: str) -> str:
+    """
+    Run clangd --check on a source file to get compiler diagnostics without a full build.
+    Much faster than build() for catching type errors, missing includes, and syntax mistakes
+    during first-pass implementation. Requires compile_commands.json to exist (from a prior build).
+
+    Args:
+        file: Path to the .cpp or .h file to check, relative to the project root.
+    """
+    _LOG_PREFIX = re.compile(r"^[IWE]\[\d{2}:\d{2}:\d{2}\.\d{3}\] ")
+    _DIAG_LINE = re.compile(r"^E\[\d{2}:\d{2}:\d{2}\.\d{3}\] (?!.*tweak:)(?!.*==> )")
+    _SUMMARY = re.compile(r"^I\[\d{2}:\d{2}:\d{2}\.\d{3}\] All checks completed")
+
+    args = [
+        "clangd",
+        f"--check={file}",
+        "--compile-commands-dir=build",
+    ]
+    print(f"[nx-decomp-tools] {' '.join(args)}", file=sys.stderr, flush=True)
+    result = subprocess.run(
+        args, cwd=PROJECT_ROOT, capture_output=True, text=True, timeout=120
+    )
+    raw = _ANSI_ESCAPE.sub("", result.stderr)
+
+    diags = []
+    summary = None
+    for line in raw.splitlines():
+        if _DIAG_LINE.match(line):
+            diags.append(_LOG_PREFIX.sub("", line))
+        elif _SUMMARY.match(line):
+            summary = _LOG_PREFIX.sub("", line)
+
+    if summary is None:
+        return f"clangd: no output (exit {result.returncode})"
+
+    summary = re.sub(r"\d+ errors?", f"{len(diags)} error{'s' if len(diags) != 1 else ''}", summary)
+    return "\n".join(diags + [summary])
+
+
+@mcp.tool()
+def check_format() -> str:
+    """
+    Run tools/check-format.py to report formatting problems.
+    Fix all reported issues before considering a class done.
+    """
+    return _run(["tools/check-format.py"], timeout=60)
+
+
+if __name__ == "__main__":
+    mcp.run()