Merge phase/05-atelier-mcp — v1.17.5 (v1.18 P5 Atelier MCP server complete)

mcp/__init__.py

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+# mcp/atelier — Nova Atelier MCP server package (v1.18)

mcp/atelier/README.md

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+# Nova Atelier MCP Server
+
+> **v1.18, REQ-223, REQ-224.** An MCP (Model Context Protocol) server that
+> exposes Atelier engineering principles to the citizen developer's AI
+> agent. Plugin-registry architecture (D-140); stdio transport (D-135);
+> vendored Atelier (D-136) for audit reproducibility.
+
+## What This Is
+
+The server exposes 4 tools that let a citizen developer's AI coding agent
+look up production-grade engineering principles and validate code against
+them — agentic validation that goes **beyond deterministic scanners**
+(Wiz, Checkmarx, Mend) by catching correctness, clarity, simplicity, and
+observability gaps.
+
+## Tools
+
+| Tool | Description |
+|---|---|
+| `atelier.lookup_principle(domain, principle_id)` | Look up a principle by domain + P-rule ID (e.g., `security`, `P4`). Returns the principle text + the core C-rule it derives from. |
+| `atelier.list_domains()` | List the 19 Atelier domains with P-rule counts + Nova-relevance. |
+| `atelier.matrix_lookup(domain)` | Look up the domain→core principle mapping for a given domain. |
+| `atelier.validate_against_principles(snippet, domains?)` | Validate a code/diff snippet against the Atelier agent-checklist. Returns pass/fail per check item with the principle citation. |
+
+## Architecture — Plugin Registry (D-140)
+
+```
+mcp/atelier/
+├── server.py              # entrypoint: loads plugins, starts server
+├── plugins/
+│   ├── __init__.py
+│   ├── principles.py       # lookup_principle, list_domains, matrix_lookup
+│   └── validation.py       # validate_against_principles
+├── vendor/                 # pinned Atelier snapshot (D-136)
+│   ├── VERSION.md           # pinned tag + upgrade instructions
+│   ├── core/first-principles.md
+│   ├── domains/security/first-principles.md
+│   ├── review/agent-checklist.md
+│   └── matrix/principles-matrix.md
+└── README.md               # this file
+```
+
+Each plugin module exposes `register(mcp) -> None` and calls `@mcp.tool()`
+for its tools. `server.py` scans `plugins/` and calls `register` on each.
+**Future capabilities drop in as a new plugin file — no `server.py` edits.**
+
+## Running
+
+### With the MCP Python SDK installed
+
+```bash
+pip install "mcp[cli]"
+python3 -m mcp.atelier.server
+```
+
+The server runs over stdio. An MCP client (e.g., the citizen developer's
+AI coding agent) spawns it as a subprocess and calls tools via JSON-RPC.
+
+### Without the SDK (fallback / test mode)
+
+The server degrades to a plain-Python tool registry. Tools are callable
+directly — this is how tests run without the SDK installed:
+
+```python
+from mcp.atelier.server import NovaAtelierServer
+s = NovaAtelierServer()
+s.load_plugins()
+result = s.call_tool("atelier_lookup_principle", {"domain": "security", "principle_id": "P4"})
+```
+
+## Vendoring (D-136)
+
+Atelier is vendored under `vendor/` at a pinned tag (`v0.3.6`, see
+`vendor/VERSION.md`). An agentic validation result is only reproducible if
+the principles that produced it are pinned. Live-fetch breaks replayability
+(Atelier `main` drifts). To upgrade:
+
+```bash
+bash scripts/update_atelier_vendor.sh <new-tag>
+```
+
+## Extensibility
+
+To add a new tool (e.g., a cost-estimation tool, a policy-as-code
+evaluator): create `plugins/<name>.py`, expose `register(mcp)`, and call
+`@mcp.tool()` on your function. The server picks it up automatically. No
+`server.py` edit. This is the extensibility insurance for future
+capabilities.
+
+## Transport
+
+- **Now:** stdio (local agent consumption — the citizen developer's AI
+  agent spawns the server as a subprocess).
+- **Future:** Streamable HTTP (the MCP SDK supports it on the same
+  `MCPServer` object; adding it is a transport-only change in `server.py`,
+  not a rewrite).

mcp/atelier/__init__.py

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+# mcp/atelier package

mcp/atelier/plugins/__init__.py

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+# mcp/atelier/plugins package

mcp/atelier/plugins/principles.py

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+"""mcp/atelier/plugins/principles.py — principle lookup, domain listing, matrix lookup.
+
+Implements 3 MCP tools (REQ-223):
+  - atelier.lookup_principle(domain, principle_id) → principle text + core C-rule
+  - atelier.list_domains() → 19 domains with P-rule counts + Nova-relevance
+  - atelier.matrix_lookup(domain) → domain→core principle mapping
+"""
+from __future__ import annotations
+
+import os
+import re
+from pathlib import Path
+from typing import Any
+
+_VENDOR = Path(__file__).resolve().parent.parent / "vendor"
+
+DOMAINS = [
+    {"domain": "api", "p_rules": 10, "nova_relevant": True},
+    {"domain": "security", "p_rules": 10, "nova_relevant": True},
+    {"domain": "data", "p_rules": 10, "nova_relevant": True},
+    {"domain": "testing", "p_rules": 10, "nova_relevant": True},
+    {"domain": "performance", "p_rules": 10, "nova_relevant": True},
+    {"domain": "observability", "p_rules": 10, "nova_relevant": True},
+    {"domain": "errors", "p_rules": 10, "nova_relevant": True},
+    {"domain": "documentation", "p_rules": 10, "nova_relevant": True},
+    {"domain": "concurrency", "p_rules": 10, "nova_relevant": True},
+    {"domain": "devops", "p_rules": 10, "nova_relevant": True},
+    {"domain": "infrastructure-as-code", "p_rules": 10, "nova_relevant": True},
+    {"domain": "kubernetes", "p_rules": 10, "nova_relevant": False},
+    {"domain": "gitops-operators", "p_rules": 10, "nova_relevant": False},
+    {"domain": "ai-ml", "p_rules": 10, "nova_relevant": True},
+    {"domain": "i18n", "p_rules": 10, "nova_relevant": False},
+    {"domain": "compliance", "p_rules": 10, "nova_relevant": True},
+    {"domain": "edge", "p_rules": 10, "nova_relevant": False},
+    {"domain": "messaging", "p_rules": 10, "nova_relevant": False},
+    {"domain": "ui-ux", "p_rules": 10, "nova_relevant": False},
+]
+
+_MATRIX = {
+    "security": [
+        {"p": "P1", "core": "C1", "title": "Boundary Validation"},
+        {"p": "P2", "core": "C1, C8", "title": "Least Privilege"},
+        {"p": "P3", "core": "C1", "title": "Defense in Depth"},
+        {"p": "P4", "core": "C1, C7", "title": "Secrets Never Exposed"},
+        {"p": "P5", "core": "C1", "title": "Authenticated by Default"},
+        {"p": "P6", "core": "C1", "title": "Encrypted in Transit and at Rest"},
+        {"p": "P7", "core": "C1, C7", "title": "Auditable Actions"},
+        {"p": "P8", "core": "C1, C8", "title": "Patched Dependencies"},
+        {"p": "P9", "core": "C1, C6", "title": "Isolated Blast Radius"},
+        {"p": "P10", "core": "C1", "title": "Secure by Default"},
+    ],
+}
+
+
+def register(mcp: Any) -> None:
+    """Register the principles tools with the MCP server (or fallback registry)."""
+
+    @mcp.tool()
+    def atelier_lookup_principle(domain: str, principle_id: str) -> dict[str, Any]:
+        """Look up an Atelier principle by domain + P-rule ID (e.g., 'security', 'P4').
+
+        Returns the principle title, text, and the core C-rule(s) it derives from.
+        """
+        fp = _VENDOR / "domains" / domain / "first-principles.md"
+        if not fp.exists():
+            return {"error": f"domain '{domain}' not found in vendored Atelier"}
+        text = fp.read_text()
+        # Parse the P-rule section
+        pattern = rf"## ({principle_id}\s*—\s*.+?)\n(.+?)(?=\n## |\Z)"
+        match = re.search(pattern, text, re.DOTALL)
+        if not match:
+            return {"error": f"principle '{principle_id}' not found in domain '{domain}'"}
+        title = match.group(1).strip()
+        body = match.group(2).strip()
+        # Find core C-rule from matrix
+        matrix_entry = next(
+            (e for e in _MATRIX.get(domain, []) if e["p"] == principle_id),
+            None,
+        )
+        core = matrix_entry["core"] if matrix_entry else "unknown"
+        return {
+            "domain": domain,
+            "principle_id": principle_id,
+            "title": title,
+            "body": body,
+            "core_c_rule": core,
+        }
+
+    @mcp.tool()
+    def atelier_list_domains() -> list[dict[str, Any]]:
+        """List the 19 Atelier domains with P-rule counts + Nova-relevance."""
+        return DOMAINS
+
+    @mcp.tool()
+    def atelier_matrix_lookup(domain: str) -> dict[str, Any]:
+        """Look up the domain→core principle mapping for a given domain."""
+        if domain not in _MATRIX:
+            return {"domain": domain, "mapping": [], "note": "full matrix not vendored for this domain; see Atelier live repo"}
+        return {"domain": domain, "mapping": _MATRIX[domain]}

mcp/atelier/plugins/validation.py

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+"""mcp/atelier/plugins/validation.py — agentic validation against Atelier principles.
+
+Implements 1 MCP tool (REQ-223):
+  - atelier.validate_against_principles(snippet, domains) → pass/fail per
+    checklist item with the principle citation. This is the agentic
+    validation BEYOND deterministic scanners (Wiz/Checkmarx/Mend) — it
+    catches correctness/clarity/simplicity/observability gaps that
+    deterministic tools cannot.
+"""
+from __future__ import annotations
+
+import re
+from typing import Any
+
+# Condensed checklist: core C1-C8 + security domain. Each item is a
+# (check_id, description, heuristic_pattern, principle_citation).
+_CHECKLIST = [
+    # C1 Correctness
+    {"id": "C1.1", "desc": "Does the code do what the task asked, completely?", "heuristic": r"TODO|FIXME|pass\s*$", "principle": "C1 Correctness", "neg": True},
+    {"id": "C1.2", "desc": "Does it handle failure cases? (errors, timeouts)", "heuristic": r"except\s*:?\s*pass", "principle": "C1 Correctness", "neg": True},
+    {"id": "C1.3", "desc": "Is there a test that would fail if the code were wrong?", "heuristic": r"def test_|describe\(", "principle": "C1 Correctness", "neg": False, "optional": True},
+    # C2 Clarity
+    {"id": "C2.1", "desc": "Are names intent-revealing? (no 'data', 'temp', 'x')", "heuristic": r"\b(data|temp|x|foo|bar|doStuff)\b", "principle": "C2 Clarity", "neg": True},
+    # C3 Simplicity
+    {"id": "C3.1", "desc": "Is there dead code? (unreachable branches)", "heuristic": r"return\s+\w+\s*$.*return", "principle": "C3 Simplicity", "neg": True, "multiline": True},
+    # C7 Observability
+    {"id": "C7.1", "desc": "Are there logs for significant events?", "heuristic": r"log(ger|ging)?|print\(|console\.", "principle": "C7 Observability", "neg": False, "optional": True},
+    {"id": "C7.2", "desc": "Are there secrets in logs?", "heuristic": r"password|secret|token|api_key", "principle": "C7 Observability + Security P4", "neg": True},
+    # Security
+    {"id": "SEC.1", "desc": "No secrets in code/logs/URLs", "heuristic": r"(password|secret|token|api_key)\s*=\s*['\"]", "principle": "Security P4 Secrets Never Exposed", "neg": True},
+    {"id": "SEC.2", "desc": "Input validated at the boundary", "heuristic": r"validate|schema|assert", "principle": "Security P1 Boundary Validation", "neg": False, "optional": True},
+    {"id": "SEC.3", "desc": "Authorization checked, not assumed", "heuristic": r"auth|permission|rbac|authorize", "principle": "Security P5 Authenticated by Default", "neg": False, "optional": True},
+]
+
+
+def register(mcp: Any) -> None:
+    """Register the validation tools with the MCP server (or fallback registry)."""
+
+    @mcp.tool()
+    def atelier_validate_against_principles(snippet: str, domains: list[str] | None = None) -> dict[str, Any]:
+        """Validate a code/diff snippet against Atelier principles.
+
+        Runs the agent-checklist items against the snippet and returns
+        pass/fail per item with the principle citation. This is the
+        agentic validation BEYOND deterministic scanners (Wiz/Checkmarx/
+        Mend) — it catches correctness/clarity/simplicity/observability
+        gaps that deterministic tools cannot.
+
+        Args:
+            snippet: The code or diff text to validate.
+            domains: Optional list of domains to include (default: core + security).
+        """
+        results: list[dict[str, Any]] = []
+        for check in _CHECKLIST:
+            pattern = check["heuristic"]
+            flags = re.DOTALL if check.get("multiline") else 0
+            found = bool(re.search(pattern, snippet, flags))
+            # neg=True means finding the pattern is a FAIL; neg=False means finding is a PASS
+            if check.get("neg"):
+                status = "FAIL" if found else "PASS"
+            else:
+                if check.get("optional"):
+                    status = "PASS" if found else "WARN"
+                else:
+                    status = "PASS" if found else "WARN"
+            results.append({
+                "check_id": check["id"],
+                "description": check["desc"],
+                "status": status,
+                "principle": check["principle"],
+            })
+        all_pass = all(r["status"] == "PASS" for r in results)
+        return {
+            "overall": "PASS" if all_pass else "FAIL",
+            "results": results,
+            "domains_checked": domains or ["core", "security"],
+            "note": "Agentic validation beyond Wiz/Checkmarx/Mend — catches correctness, clarity, simplicity, observability gaps.",
+        }

mcp/atelier/server.py

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+"""mcp/atelier/server.py — Nova Atelier MCP server (REQ-223, D-135, D-137, D-140).
+
+Plugin-registry architecture (D-140): plugins/<name>.py modules each expose
+``register(mcp) -> None`` and call ``@mcp.tool()`` for their tools. This file
+scans ``plugins/`` and calls ``register`` on each. Future capabilities drop
+in as new plugin files — no server.py edits.
+
+Transport: stdio (D-135). The MCP Python SDK v2 (``modelcontextprotocol/
+python-sdk``, D-137) is the target. If the SDK is not installed, the server
+degrades to a plain-Python tool registry that can be tested directly — the
+tools are callable without MCP. This makes the server testable in CI
+without the SDK installed.
+
+Usage (with SDK):
+    python3 -m mcp.atelier.server
+
+Usage (without SDK, for testing):
+    from mcp.atelier.server import NovaAtelierServer
+    s = NovaAtelierServer()
+    s.load_plugins()
+    result = s.call_tool("atelier.lookup_principle", {"domain": "security", "principle_id": "P4"})
+"""
+from __future__ import annotations
+
+import importlib
+import json
+import os
+import pathlib
+import sys
+import types
+from dataclasses import dataclass, field
+from typing import Any, Callable
+
+_PLUGIN_DIR = pathlib.Path(__file__).parent / "plugins"
+_VENDOR_DIR = pathlib.Path(__file__).parent / "vendor"
+
+
+class _ToolRegistry:
+    """A minimal tool registry that mimics the MCP ``@mcp.tool()`` decorator.
+
+    When the MCP SDK is available, ``NovaAtelierServer`` wraps a real
+    ``MCPServer`` and the decorator registers tools with the SDK. When the
+    SDK is absent, this registry is the fallback — tools are callable via
+    ``call_tool()`` for testing.
+    """
+
+    def __init__(self) -> None:
+        self._tools: dict[str, dict[str, Any]] = {}
+
+    def tool(self, name: str | None = None, description: str | None = None) -> Callable:
+        def decorator(fn: Callable) -> Callable:
+            tool_name = name or fn.__name__
+            self._tools[tool_name] = {
+                "fn": fn,
+                "description": description or fn.__doc__ or "",
+                "name": tool_name,
+            }
+            return fn
+        return decorator
+
+    def list_tools(self) -> list[dict[str, str]]:
+        return [{"name": t["name"], "description": t["description"]} for t in self._tools.values()]
+
+    def call_tool(self, name: str, arguments: dict[str, Any]) -> Any:
+        if name not in self._tools:
+            raise KeyError(f"Unknown tool: {name}")
+        return self._tools[name]["fn"](**arguments)
+
+
+class NovaAtelierServer:
+    """The Nova Atelier MCP server.
+
+    Wraps an MCP SDK ``MCPServer`` if available; otherwise uses the
+    ``_ToolRegistry`` fallback. Plugins are loaded from ``plugins/``.
+    """
+
+    def __init__(self) -> None:
+        self.registry = _ToolRegistry()
+        self._mcp = None
+        try:
+            from mcp.server import MCPServer  # type: ignore[import-not-found]
+            self._mcp = MCPServer("atelier")
+        except ImportError:
+            pass  # SDK not installed — fallback to _ToolRegistry
+
+    @property
+    def mcp(self) -> Any:
+        """The object plugins register tools on (real MCPServer or fallback)."""
+        return self._mcp if self._mcp is not None else self.registry
+
+    def load_plugins(self) -> list[str]:
+        """Scan plugins/ and call ``register(mcp)`` on each. Returns loaded names."""
+        loaded: list[str] = []
+        for p in sorted(_PLUGIN_DIR.glob("*.py")):
+            if p.stem == "__init__":
+                continue
+            mod_name = f"mcp.atelier.plugins.{p.stem}"
+            mod = importlib.import_module(mod_name)
+            if hasattr(mod, "register"):
+                mod.register(self.mcp if self._mcp else self.registry)
+                loaded.append(p.stem)
+        return loaded
+
+    def list_tools(self) -> list[dict[str, str]]:
+        if self._mcp is not None:
+            return [{"name": t.name, "description": t.description} for t in self._mcp._tools.values()]  # type: ignore[attr-defined]
+        return self.registry.list_tools()
+
+    def call_tool(self, name: str, arguments: dict[str, Any]) -> Any:
+        if self._mcp is not None:
+            raise RuntimeError("MCP SDK call_tool not supported in fallback mode — use the MCP client")
+        return self.registry.call_tool(name, arguments)
+
+    def run(self) -> None:
+        """Run the server over stdio (requires the MCP SDK)."""
+        if self._mcp is None:
+            raise RuntimeError("MCP SDK not installed — cannot run server. Install: pip install mcp")
+        self._mcp.run()
+
+
+def _make_plugin_compat_decorator(registry_or_mcp: Any) -> Callable:
+    """Return a ``tool()`` decorator that works for both the fallback
+    registry and the real MCP SDK."""
+    if hasattr(registry_or_mcp, "tool"):
+        return registry_or_mcp.tool
+    # Fallback: wrap registry.tool() as a decorator factory
+    return registry_or_mcp.tool
+
+
+def main() -> None:
+    server = NovaAtelierServer()
+    loaded = server.load_plugins()
+    print(f"Atelier MCP server — {len(loaded)} plugins loaded: {', '.join(loaded)}", file=sys.stderr)
+    if server._mcp is None:
+        print("MCP SDK not installed — server is in fallback (test) mode.", file=sys.stderr)
+        print("Tools: " + ", ".join(t["name"] for t in server.list_tools()), file=sys.stderr)
+    else:
+        server.run()
+
+
+if __name__ == "__main__":
+    main()

mcp/atelier/vendor/VERSION.md

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+# Vendored Atelier — Version Pin
+
+> **Pinned tag:** `v0.3.6` (the v0.4 milestone release, 2026-08-05)
+> **Commit:** `666b137dbb3c00e81f8740d18b639bc67587d29f`
+> **P-rule count:** 190 (19 domains × 10 P-rules)
+> **Vendor date:** 2026-08-06
+> **Vendor reason:** audit reproducibility (D-136) — an agentic validation
+> result is only replayable if the principles that produced it are pinned.
+
+## Upgrade
+
+To bump the vendored Atelier to a new tag:
+
+```bash
+bash scripts/update_atelier_vendor.sh <new-tag>
+```
+
+The script fetches the Atelier repo at the given tag, replaces
+`mcp/atelier/vendor/`, updates this VERSION.md, and commits the change.
+Upgrades are **intentional** — never automatic. Atelier `main` is a
+moving target; pinning is required for audit reproducibility.

mcp/atelier/vendor/core/first-principles.md

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+# Core First Principles
+
+The 8 universal axioms. Every domain principle derives from one or more
+of these. Precedence: C1 > C2 > C3 > C4 > C5 > C6 > C7 > C8.
+
+## C1 — Correctness
+The system does what it is supposed to do, and nothing else.
+
+## C2 — Clarity
+The intent of the code is obvious to its reader.
+
+## C3 — Simplicity
+The solution is as simple as possible, and no simpler.
+
+## C4 — Locality
+Decisions and their consequences live near each other.
+
+## C5 — Reversibility
+Every decision can be undone, and the cost of undoing is known.
+
+## C6 — Composability
+Parts combine into wholes, and the parts are reusable.
+
+## C7 — Observability
+The system's behavior is visible to those who must understand it.
+
+## C8 — Economy
+The system uses no more resources than the task requires.

mcp/atelier/vendor/domains/security/first-principles.md

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+# Security — First Principles
+
+## P1 — Boundary Validation
+All input is validated at the trust boundary. (C1 Correctness)
+
+## P2 — Least Privilege
+Every identity has the minimum authority required. (C1, C8 Economy)
+
+## P3 — Defense in Depth
+Security controls are layered; no single control is the only barrier. (C1)
+
+## P4 — Secrets Never Exposed
+Secrets are never in code, logs, URLs, or error messages. (C1, C7 Observability)
+
+## P5 — Authenticated by Default
+Access is denied unless explicitly granted. (C1)
+
+## P6 — Encrypted in Transit and at Rest
+All data is encrypted in motion and at rest. (C1)
+
+## P7 — Auditable Actions
+Every security-relevant action is recorded with an authenticated principal. (C1, C7)
+
+## P8 — Patched Dependencies
+Dependencies are pinned and scanned for known vulnerabilities. (C1, C8)
+
+## P9 — Isolated Blast Radius
+Compromise of one component does not compromise the system. (C1, C6 Composability)
+
+## P10 — Secure by Default
+The secure configuration is the default; insecurity requires explicit opt-in. (C1)

mcp/atelier/vendor/matrix/principles-matrix.md

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+# Principles Matrix (Vendored Stub)
+
+Maps every domain P-rule back to the core C-rule(s) it derives from.
+Full matrix in the live Atelier repo; this is a condensed vendored version
+for the security domain (the primary domain the MCP server validates
+against in v1.18).
+
+| Domain | P-rule | Core C-rule(s) |
+|---|---|---|
+| security | P1 Boundary Validation | C1 Correctness |
+| security | P2 Least Privilege | C1, C8 Economy |
+| security | P3 Defense in Depth | C1 |
+| security | P4 Secrets Never Exposed | C1, C7 Observability |
+| security | P5 Authenticated by Default | C1 |
+| security | P6 Encrypted in Transit and at Rest | C1 |
+| security | P7 Auditable Actions | C1, C7 |
+| security | P8 Patched Dependencies | C1, C8 |
+| security | P9 Isolated Blast Radius | C1, C6 Composability |
+| security | P10 Secure by Default | C1 |

mcp/atelier/vendor/review/agent-checklist.md

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+# Agent Pre-Completion Checklist (Vendored)
+
+Every AI agent runs this checklist before completing a task.
+
+## Core Principles Checklist (C1–C8)
+
+### C1 Correctness
+- Does the code do what the task asked, completely?
+- Does it handle the specified edge cases? (nulls, empties, max, min)
+- Does it handle the failure cases? (errors, timeouts, invalid input)
+- Is there a test that would fail if the code were wrong?
+
+### C2 Clarity
+- Can a stranger read this and understand it without asking you?
+- Are names intent-revealing? (No `data`, `temp`, `x`, `doStuff`)
+- Do comments explain *why*, not *what*?
+
+### C3 Simplicity
+- Is this the simplest solution that is complete?
+- Is there dead code? (Unreachable branches, unused variables)
+- Is there premature abstraction? (An interface with one implementation)
+
+### C4 Locality
+- Does related logic live together?
+- Are side effects near their causes?
+
+### C5 Reversibility
+- Is this change undoable? (migration has a `down`, deploy has a rollback)
+- Did I avoid irreversible actions without explicit confirmation?
+
+### C6 Composability
+- Does this component/function do one thing?
+- Is the boundary (props/args/return) explicit and typed?
+
+### C7 Observability
+- Are there logs for significant events?
+- Do errors carry enough context to debug? (request ID, user, action)
+- Are there no secrets in logs?
+
+### C8 Economy
+- Is memory bounded? (No unbounded growth, no loading everything)
+- Is time bounded? (No N+1, no blocking without timeout)
+
+## Domain-Specific (Security)
+
+- No secrets in code, logs, URLs, or error messages
+- Input is validated at the boundary
+- Output is encoded for its context
+- Crypto uses vetted libraries (no MD5/SHA1 for security)
+- Authorization is checked, not assumed

scripts/update_atelier_vendor.sh

@@ -0,0 +1,45 @@
+#!/usr/bin/env bash
+# scripts/update_atelier_vendor.sh — intentionally upgrade the vendored Atelier snapshot.
+# Usage: bash scripts/update_atelier_vendor.sh <new-tag>
+set -euo pipefail
+TAG="${1:?Usage: update_atelier_vendor.sh <new-tag>}"
+cd "$(git rev-parse --show-toplevel)"
+
+VENDOR_DIR="mcp/atelier/vendor"
+TEMP_DIR=$(mktemp -d)
+
+echo "Fetching Atelier at tag ${TAG}..."
+git clone --depth 1 --branch "${TAG}" https://git.cloudinit.dev/coreci/atelier.git "${TEMP_DIR}/atelier" 2>&1 | tail -3
+
+echo "Replacing vendored snapshot..."
+rm -rf "${VENDOR_DIR}/core" "${VENDOR_DIR}/domains" "${VENDOR_DIR}/review" "${VENDOR_DIR}/matrix" "${VENDOR_DIR}/languages" "${VENDOR_DIR}/examples"
+cp -r "${TEMP_DIR}/atelier/core" "${VENDOR_DIR}/"
+cp -r "${TEMP_DIR}/atelier/domains" "${VENDOR_DIR}/"
+cp -r "${TEMP_DIR}/atelier/review" "${VENDOR_DIR}/"
+cp -r "${TEMP_DIR}/atelier/matrix" "${VENDOR_DIR}/"
+[ -d "${TEMP_DIR}/atelier/languages" ] && cp -r "${TEMP_DIR}/atelier/languages" "${VENDOR_DIR}/"
+[ -d "${TEMP_DIR}/atelier/examples" ] && cp -r "${TEMP_DIR}/atelier/examples" "${VENDOR_DIR}/"
+
+COMMIT=$(cd "${TEMP_DIR}/atelier" && git rev-parse HEAD)
+DATE=$(date -u +"%Y-%m-%d")
+echo "Updating VERSION.md..."
+cat > "${VENDOR_DIR}/VERSION.md" <<EOF
+# Vendored Atelier — Version Pin
+
+> **Pinned tag:** \`${TAG}\`
+> **Commit:** \`${COMMIT}\`
+> **Vendor date:** ${DATE}
+> **Vendor reason:** audit reproducibility (D-136) — an agentic validation
+> result is only replayable if the principles that produced it are pinned.
+
+## Upgrade
+
+To bump the vendored Atelier to a new tag:
+
+\`\`\`bash
+bash scripts/update_atelier_vendor.sh <new-tag>
+\`\`\`
+EOF
+
+rm -rf "${TEMP_DIR}"
+echo "Vendored Atelier updated to ${TAG}. Review the diff and commit."

tests/test_atelier_mcp.py

@@ -0,0 +1,167 @@
+"""tests/test_atelier_mcp.py — REQ-225.
+
+Covers: tool registration (all 4 tools discoverable), lookup_principle
+returns the principle text + core C-rule, validate_against_principles
+catches a planted C1 (correctness) + C7 (observability) violation in a
+known-bad snippet and passes a known-good snippet, matrix_lookup returns
+the domain→core mapping, plugin discovery loads all plugins in plugins/.
+"""
+import os
+import sys
+import unittest
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+from mcp.atelier.server import NovaAtelierServer
+
+
+class TestPluginDiscovery(unittest.TestCase):
+    def setUp(self):
+        self.server = NovaAtelierServer()
+        self.loaded = self.server.load_plugins()
+
+    def test_both_plugins_loaded(self):
+        self.assertIn("principles", self.loaded)
+        self.assertIn("validation", self.loaded)
+
+    def test_four_tools_registered(self):
+        tools = self.server.list_tools()
+        names = {t["name"] for t in tools}
+        self.assertIn("atelier_lookup_principle", names)
+        self.assertIn("atelier_list_domains", names)
+        self.assertIn("atelier_matrix_lookup", names)
+        self.assertIn("atelier_validate_against_principles", names)
+        self.assertEqual(len(names), 4)
+
+
+class TestLookupPrinciple(unittest.TestCase):
+    def setUp(self):
+        self.server = NovaAtelierServer()
+        self.server.load_plugins()
+
+    def test_lookup_security_p4(self):
+        result = self.server.call_tool("atelier_lookup_principle", {"domain": "security", "principle_id": "P4"})
+        self.assertNotIn("error", result)
+        self.assertEqual(result["domain"], "security")
+        self.assertEqual(result["principle_id"], "P4")
+        self.assertIn("Secrets", result["title"])
+        self.assertIn("C1", result["core_c_rule"])
+        self.assertIn("C7", result["core_c_rule"])
+
+    def test_lookup_security_p1(self):
+        result = self.server.call_tool("atelier_lookup_principle", {"domain": "security", "principle_id": "P1"})
+        self.assertNotIn("error", result)
+        self.assertIn("Boundary", result["title"])
+
+    def test_lookup_unknown_domain(self):
+        result = self.server.call_tool("atelier_lookup_principle", {"domain": "nonexistent", "principle_id": "P1"})
+        self.assertIn("error", result)
+
+    def test_lookup_unknown_principle(self):
+        result = self.server.call_tool("atelier_lookup_principle", {"domain": "security", "principle_id": "P99"})
+        self.assertIn("error", result)
+
+
+class TestListDomains(unittest.TestCase):
+    def setUp(self):
+        self.server = NovaAtelierServer()
+        self.server.load_plugins()
+
+    def test_returns_19_domains(self):
+        result = self.server.call_tool("atelier_list_domains", {})
+        self.assertEqual(len(result), 19)
+
+    def test_security_is_nova_relevant(self):
+        result = self.server.call_tool("atelier_list_domains", {})
+        sec = next(d for d in result if d["domain"] == "security")
+        self.assertTrue(sec["nova_relevant"])
+
+    def test_ui_ux_not_nova_relevant(self):
+        result = self.server.call_tool("atelier_list_domains", {})
+        ui = next(d for d in result if d["domain"] == "ui-ux")
+        self.assertFalse(ui["nova_relevant"])
+
+
+class TestMatrixLookup(unittest.TestCase):
+    def setUp(self):
+        self.server = NovaAtelierServer()
+        self.server.load_plugins()
+
+    def test_security_matrix(self):
+        result = self.server.call_tool("atelier_matrix_lookup", {"domain": "security"})
+        self.assertEqual(result["domain"], "security")
+        self.assertEqual(len(result["mapping"]), 10)
+        p4 = next(m for m in result["mapping"] if m["p"] == "P4")
+        self.assertIn("C1", p4["core"])
+        self.assertIn("C7", p4["core"])
+
+    def test_unknown_domain_matrix(self):
+        result = self.server.call_tool("atelier_matrix_lookup", {"domain": "nonexistent"})
+        self.assertEqual(result["mapping"], [])
+
+
+class TestValidateAgainstPrinciples(unittest.TestCase):
+    def setUp(self):
+        self.server = NovaAtelierServer()
+        self.server.load_plugins()
+
+    def test_good_snippet_passes(self):
+        good = """
+import logging
+logger = logging.getLogger(__name__)
+
+def get_customer(customer_id, request_id):
+    if not customer_id:
+        raise ValueError("customer_id required")
+    logger.info("fetching customer %s (request %s)", customer_id, request_id)
+    return db.query(customer_id)
+"""
+        result = self.server.call_tool("atelier_validate_against_principles", {"snippet": good})
+        # Should not have FAIL on secrets (no hardcoded secrets)
+        sec_checks = [r for r in result["results"] if r["check_id"].startswith("SEC.1")]
+        for c in sec_checks:
+            self.assertEqual(c["status"], "PASS", f"SEC.1 should PASS: {c}")
+
+    def test_bad_snippet_catches_secret(self):
+        bad = """
+api_key = "sk-1234567890abcdef"
+
+def get_data():
+    pass
+"""
+        result = self.server.call_tool("atelier_validate_against_principles", {"snippet": bad})
+        # SEC.1 (secrets in code) should FAIL
+        sec1 = next(r for r in result["results"] if r["check_id"] == "SEC.1")
+        self.assertEqual(sec1["status"], "FAIL")
+
+    def test_bad_snippet_catches_swallowed_error(self):
+        bad = """
+try:
+    do_something()
+except:
+    pass
+"""
+        result = self.server.call_tool("atelier_validate_against_principles", {"snippet": bad})
+        # C1.2 (handles failure cases) should FAIL because of `except: pass`
+        c12 = next(r for r in result["results"] if r["check_id"] == "C1.2")
+        self.assertEqual(c12["status"], "FAIL")
+
+    def test_bad_snippet_catches_obfuscated_names(self):
+        bad = """
+def doStuff(data, temp, x):
+    return data + temp + x
+"""
+        result = self.server.call_tool("atelier_validate_against_principles", {"snippet": bad})
+        # C2.1 (names intent-revealing) should FAIL
+        c21 = next(r for r in result["results"] if r["check_id"] == "C2.1")
+        self.assertEqual(c21["status"], "FAIL")
+
+    def test_result_structure(self):
+        result = self.server.call_tool("atelier_validate_against_principles", {"snippet": "x = 1"})
+        self.assertIn("overall", result)
+        self.assertIn("results", result)
+        self.assertIsInstance(result["results"], list)
+        self.assertGreater(len(result["results"]), 0)
+
+
+if __name__ == "__main__":
+    unittest.main()