add nested proof check provider

.gitignore

@@ -4,6 +4,8 @@
 .pytest_cache/
 artifacts*/
 repos/
+provider/out/
+provider/state/
 __pycache__/
 *.py[cod]
 *.egg-info/

README.md

@@ -89,12 +89,42 @@ pacta agent --config examples/repos.yaml \
   --repo-name dalek-ed25519-verified \
   --attestation examples/dalek-ed25519.attestation.yaml \
   --trust-attestation-provider example-proof-checker.invalid \
+  --allow-unsigned-attestation \
   --action build-library
 ```
 
 This changes the trusted base. The agent is no longer trusting local Lean replay; it is trusting the proof-checking service, its environment, signing key custody, and log retention. Without an explicitly trusted provider, attestation evidence scores `R0`.
 
-The included `examples/dalek-ed25519.attestation.yaml` is a schema/demo fixture. A production service should publish verifiable signatures, transparency-log entries, and reproducible logs; the prototype records signature metadata but does not yet implement cryptographic signature verification.
+The included `examples/dalek-ed25519.attestation.yaml` is an unsigned schema/demo fixture and requires `--allow-unsigned-attestation`. Real provider certificates should be signed and consumed with `--attestation-public-key`.
+
+## Nested Proof-Check Provider
+
+This repository includes a nested provider prototype under `provider/`. It searches read-only under your home/GitClone tree for reusable Lean/Aeneas infrastructure, runs the proof replay, signs the result with OpenSSL Ed25519, and emits an attestation.
+
+```bash
+PYTHONPATH=src:provider/src python -m pacta_provider discover --root ~/GitClone
+PYTHONPATH=src:provider/src python -m pacta_provider init-key --key-dir provider/state/local-provider
+PYTHONPATH=src:provider/src python -m pacta_provider check \
+  --config examples/repos.yaml \
+  --repo-name dalek-ed25519-verified \
+  --repo repos/dalek-ed25519-verified \
+  --provider local-pacta-provider \
+  --private-key provider/state/local-provider/provider.ed25519.key \
+  --public-key provider/state/local-provider/provider.ed25519.pub \
+  --env-script /path/to/aeneas-toolchain/env.sh \
+  --lean-project-dir '$AENEAS_HOME/backends/lean' \
+  --out provider/out/dalek-ed25519.attestation.yaml
+
+pacta agent \
+  --config examples/repos.yaml \
+  --repo-name dalek-ed25519-verified \
+  --attestation provider/out/dalek-ed25519.attestation.yaml \
+  --trust-attestation-provider local-pacta-provider \
+  --attestation-public-key provider/state/local-provider/provider.ed25519.pub \
+  --action build-library
+```
+
+This is the intended trust transformation: local agents can avoid constructing the full verifier environment, but they must explicitly trust the provider identity and verification key.
 
 ## Truth Boundary
 

provider/README.md

@@ -0,0 +1,24 @@
+# PACTA Proof Check Provider
+
+This nested project is a prototype third-party proof-checking service. It reuses host Lean/Aeneas infrastructure, runs portable PACTA replay/audit checks, and emits signed attestation certificates.
+
+It does not modify anything outside this repository. It may read configured toolchains such as `/Users/oho/GitClone/ClaudeCodeProjects/your-lean-project/aeneas-toolchain/env.sh`.
+
+## Commands
+
+```bash
+PYTHONPATH=src:provider/src python -m pacta_provider discover
+PYTHONPATH=src:provider/src python -m pacta_provider init-key --key-dir provider/state/demo-provider
+PYTHONPATH=src:provider/src python -m pacta_provider check \
+  --config examples/repos.yaml \
+  --repo-name dalek-ed25519-verified \
+  --repo repos/dalek-ed25519-verified \
+  --provider local-pacta-provider \
+  --private-key provider/state/demo-provider/provider.ed25519.key \
+  --public-key provider/state/demo-provider/provider.ed25519.pub \
+  --out provider/out/dalek.attestation.yaml
+```
+
+The resulting certificate can be consumed by `pacta` with `--attestation`, `--trust-attestation-provider`, and `--attestation-public-key`.
+
+The private key must remain provider-side. Downstream agents only need the public key and a policy decision that the provider name is trusted.

provider/pyproject.toml

@@ -0,0 +1,16 @@
+[build-system]
+requires = ["setuptools>=68"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "pacta-proof-check-provider"
+version = "0.1.0"
+description = "Nested proof-checking attestation provider for PACTA."
+requires-python = ">=3.11"
+dependencies = []
+
+[project.scripts]
+pacta-provider = "pacta_provider.cli:main"
+
+[tool.setuptools.packages.find]
+where = ["src"]

provider/src/pacta_provider/__init__.py

@@ -0,0 +1,5 @@
+"""PACTA proof-checking attestation provider."""
+
+__all__ = ["__version__"]
+
+__version__ = "0.1.0"

provider/src/pacta_provider/__main__.py

@@ -0,0 +1,5 @@
+from .cli import main
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

provider/src/pacta_provider/cli.py

@@ -0,0 +1,88 @@
+from __future__ import annotations
+
+import argparse
+import json
+from pathlib import Path
+
+from pacta.config import load_config
+from pacta.signing import generate_ed25519_keypair
+from pacta.yamlio import dump_data
+
+from .discovery import discover_toolchains
+from .service import build_attestation
+
+
+def main(argv: list[str] | None = None) -> int:
+    parser = build_parser()
+    args = parser.parse_args(argv)
+    try:
+        return args.func(args)
+    except Exception as exc:
+        print(f"error: {exc}")
+        return 2
+
+
+def build_parser() -> argparse.ArgumentParser:
+    parser = argparse.ArgumentParser(prog="pacta-provider", description="PACTA proof-checking attestation provider.")
+    sub = parser.add_subparsers(dest="command", required=True)
+
+    discover = sub.add_parser("discover", help="Find reusable local Lean/Aeneas toolchains.")
+    discover.add_argument("--root", action="append")
+    discover.add_argument("--max-depth", type=int, default=6)
+    discover.set_defaults(func=cmd_discover)
+
+    init_key = sub.add_parser("init-key", help="Create an Ed25519 provider signing keypair.")
+    init_key.add_argument("--key-dir", default="provider/state/local-provider")
+    init_key.set_defaults(func=cmd_init_key)
+
+    check = sub.add_parser("check", help="Run proof checks and emit a signed attestation.")
+    check.add_argument("--config", required=True)
+    check.add_argument("--repo-name", required=True)
+    check.add_argument("--repo", required=True)
+    check.add_argument("--provider", required=True)
+    check.add_argument("--private-key", required=True)
+    check.add_argument("--public-key", required=True)
+    check.add_argument("--env-script")
+    check.add_argument("--lean-project-dir")
+    check.add_argument("--timeout", type=int, default=120)
+    check.add_argument("--log-dir", default="provider/out/logs")
+    check.add_argument("--out", required=True)
+    check.set_defaults(func=cmd_check)
+    return parser
+
+
+def cmd_discover(args: argparse.Namespace) -> int:
+    candidates = discover_toolchains(args.root, max_depth=args.max_depth)
+    print(json.dumps([candidate.to_dict() for candidate in candidates], indent=2))
+    return 0 if candidates else 1
+
+
+def cmd_init_key(args: argparse.Namespace) -> int:
+    key_dir = Path(args.key_dir)
+    private_key = key_dir / "provider.ed25519.key"
+    public_key = key_dir / "provider.ed25519.pub"
+    if private_key.exists() or public_key.exists():
+        raise ValueError(f"Refusing to overwrite existing key files in {key_dir}")
+    generate_ed25519_keypair(private_key, public_key)
+    print(f"private_key: {private_key}")
+    print(f"public_key: {public_key}")
+    return 0
+
+
+def cmd_check(args: argparse.Namespace) -> int:
+    config = load_config(args.config)
+    repo = config.repo_named(args.repo_name)
+    attestation = build_attestation(
+        repo,
+        args.repo,
+        provider=args.provider,
+        private_key=args.private_key,
+        public_key=args.public_key,
+        env_script=args.env_script,
+        lean_project_dir=args.lean_project_dir,
+        timeout=args.timeout,
+        log_dir=args.log_dir,
+    )
+    dump_data(attestation, args.out)
+    print(f"attestation: {args.out}")
+    return 0

provider/src/pacta_provider/discovery.py

@@ -0,0 +1,82 @@
+from __future__ import annotations
+
+import os
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Iterable
+
+from pacta.lean import build_lean_env, detect_tools, resolve_lean_project_dir
+
+
+SKIP_DIRS = {".git", ".venv", "__pycache__", "node_modules", "target", ".lake", ".pytest_cache"}
+
+
+@dataclass(slots=True)
+class ToolchainCandidate:
+    env_script: Path
+    lean_project_dir: Path | None
+    lean: str | None
+    lake: str | None
+    aeneas_home: str | None
+
+    def to_dict(self) -> dict[str, str | None]:
+        return {
+            "env_script": str(self.env_script),
+            "lean_project_dir": str(self.lean_project_dir) if self.lean_project_dir else None,
+            "lean": self.lean,
+            "lake": self.lake,
+            "aeneas_home": self.aeneas_home,
+        }
+
+
+def discover_toolchains(roots: Iterable[str | Path] | None = None, max_depth: int = 6) -> list[ToolchainCandidate]:
+    home = Path.home()
+    search_roots = [home / "GitClone", home] if roots is None else [Path(root).expanduser() for root in roots]
+    scripts: list[Path] = []
+    for root in search_roots:
+        if root.exists():
+            scripts.extend(_find_env_scripts(root, max_depth=max_depth))
+    candidates: list[ToolchainCandidate] = []
+    seen: set[Path] = set()
+    for script in scripts:
+        if script in seen:
+            continue
+        seen.add(script)
+        env = build_lean_env("verification", env_script=script)
+        tools = detect_tools(env)
+        project = resolve_lean_project_dir("$AENEAS_HOME/backends/lean", env)
+        if project is None:
+            project = _nearby_lean_project(script)
+        candidates.append(
+            ToolchainCandidate(
+                env_script=script,
+                lean_project_dir=project,
+                lean=tools.lean,
+                lake=tools.lake,
+                aeneas_home=env.get("AENEAS_HOME"),
+            )
+        )
+    return candidates
+
+
+def _find_env_scripts(root: Path, max_depth: int) -> list[Path]:
+    root = root.resolve()
+    found: list[Path] = []
+    for current, dirs, files in os.walk(root):
+        current_path = Path(current)
+        rel_depth = len(current_path.relative_to(root).parts)
+        if rel_depth >= max_depth:
+            dirs[:] = []
+        else:
+            dirs[:] = [d for d in dirs if d not in SKIP_DIRS]
+        if "env.sh" in files and ("aeneas" in str(current_path).lower() or "lean" in str(current_path).lower()):
+            found.append(current_path / "env.sh")
+    return sorted(found)
+
+
+def _nearby_lean_project(script: Path) -> Path | None:
+    for parent in [script.parent, *script.parents]:
+        for candidate in (parent / "aeneas" / "backends" / "lean", parent / "backends" / "lean"):
+            if (candidate / "lakefile.lean").exists() or (candidate / "lakefile.toml").exists():
+                return candidate
+    return None

provider/src/pacta_provider/service.py

@@ -0,0 +1,141 @@
+from __future__ import annotations
+
+from datetime import datetime, timezone
+from pathlib import Path
+import shutil
+import subprocess
+from typing import Any
+
+from pacta.attestation import validate_attestation
+from pacta.config import RepoConfig
+from pacta.lean import LeanCheckResult, build_lean_env, detect_tools, lean_check_files, resolve_lean_project_dir, run_axiom_audit
+from pacta.manifest import discover_layout
+from pacta.profiles import get_profile
+from pacta.repo import git_commit
+from pacta.signing import sign_attestation
+
+
+def build_attestation(
+    repo: RepoConfig,
+    repo_path: str | Path,
+    provider: str,
+    private_key: str | Path,
+    public_key: str | Path,
+    env_script: str | Path | None = None,
+    lean_project_dir: str | Path | None = None,
+    timeout: int = 120,
+    log_dir: str | Path = "provider/out/logs",
+) -> dict[str, Any]:
+    path = Path(repo_path)
+    profile = get_profile(repo.kind, repo)
+    layout = discover_layout(path, repo.verification_dir)
+    check = lean_check_files(
+        layout.compile_order,
+        layout.verification_dir,
+        timeout=timeout,
+        log_dir=log_dir,
+        env_script=env_script or repo.env_script,
+        lean_project_dir=lean_project_dir or repo.lean_project_dir,
+    )
+    axiom = None
+    if check.attempted and check.ok:
+        axiom = run_axiom_audit(
+            path / repo.verification_dir,
+            profile.axiom_imports,
+            repo.certificates or profile.default_certificates,
+            profile.expected_axioms,
+            timeout=timeout,
+            log_dir=log_dir,
+            env_script=env_script or repo.env_script,
+            lean_project_dir=lean_project_dir or repo.lean_project_dir,
+        )
+        certs = [
+            {
+                "name": cert.name,
+                "status": cert.status,
+                "axiom_status": cert.axiom_status,
+                "observed_axioms": cert.observed_axioms,
+                "expected_axioms": cert.expected_axioms,
+                "diagnostics": cert.diagnostics,
+            }
+            for cert in axiom.certificates
+        ]
+    else:
+        certs = _failed_certificates(repo, profile.expected_axioms, check)
+    provider_env = build_lean_env(path / repo.verification_dir, env_script=env_script or repo.env_script)
+    project_dir = resolve_lean_project_dir(lean_project_dir or repo.lean_project_dir, provider_env)
+    tools = detect_tools(provider_env)
+    lean_version = _project_version(["lake", "env", "lean", "--version"], project_dir, provider_env) or tools.lean_version
+    lake_version = _project_version(["lake", "--version"], project_dir, provider_env) or tools.lake_version
+    unsigned = {
+        "schema_version": 1,
+        "provider": provider,
+        "issued_at": datetime.now(timezone.utc).replace(microsecond=0).isoformat().replace("+00:00", "Z"),
+        "subject": {
+            "component": repo.name,
+            "repo_url": repo.url,
+            "repo_commit": git_commit(path),
+            "verification_dir": repo.verification_dir,
+            "kind": repo.kind,
+            "verified_backend": repo.verified_backend,
+        },
+        "environment": {
+            "lean_version": lean_version,
+            "lake_version": lake_version,
+            "env_script": str(env_script or repo.env_script or ""),
+            "lean_project_dir": str(project_dir or lean_project_dir or repo.lean_project_dir or ""),
+        },
+        "replay": {
+            "check_attempted": check.attempted,
+            "check_ok": check.ok,
+            "check_log_path": check.log_path,
+            "checked_files": len(check.checked_files),
+            "failed_files": check.failed_files,
+            "diagnostics": check.diagnostics,
+            "axiom_attempted": axiom.attempted if axiom else False,
+            "axiom_ok": axiom.ok if axiom else False,
+            "axiom_log_path": axiom.log_path if axiom else None,
+            "axiom_diagnostics": axiom.diagnostics if axiom else [],
+        },
+        "certificates": certs,
+    }
+    signed = sign_attestation(unsigned, private_key, public_key)
+    # Self-check before emitting a certificate.
+    validation = validate_attestation(signed, repo, trusted_provider=provider, public_key_path=public_key)
+    if not validation.accepted:
+        signed.setdefault("provider_warnings", []).extend(validation.diagnostics)
+    return signed
+
+
+def _failed_certificates(repo: RepoConfig, expected_axioms: list[str], check: LeanCheckResult) -> list[dict[str, Any]]:
+    return [
+        {
+            "name": name,
+            "status": "failed" if check.attempted else "unknown",
+            "axiom_status": "not_checked",
+            "observed_axioms": [],
+            "expected_axioms": expected_axioms,
+        }
+        for name in repo.certificates
+    ]
+
+
+def _project_version(cmd: list[str], cwd: Path | None, env: dict[str, str]) -> str | None:
+    executable = shutil.which(cmd[0], path=env.get("PATH"))
+    if not executable:
+        return None
+    try:
+        completed = subprocess.run(
+            [executable, *cmd[1:]],
+            check=False,
+            capture_output=True,
+            text=True,
+            timeout=20,
+            cwd=str(cwd) if cwd else None,
+            env=env,
+        )
+    except (OSError, subprocess.TimeoutExpired):
+        return None
+    if completed.returncode != 0:
+        return None
+    return (completed.stdout or completed.stderr).strip() or None

src/pacta/attestation.py

@@ -5,6 +5,7 @@ from pathlib import Path
 from typing import Any
 
 from .config import RepoConfig
+from .signing import verify_attestation_signature
 from .yamlio import load_data
 
 
@@ -31,6 +32,8 @@ def validate_attestation(
     repo: RepoConfig,
     path: str | Path | None = None,
     trusted_provider: str | None = None,
+    public_key_path: str | Path | None = None,
+    allow_unsigned: bool = False,
 ) -> AttestationResult:
     provider = raw.get("provider")
     subject = raw.get("subject") or {}
@@ -61,8 +64,21 @@ def validate_attestation(
     signature = raw.get("signature") or {}
     environment = raw.get("environment") or {}
     signature_status = signature.get("status", "not_checked")
-    if signature_status not in {"verified", "not_implemented"}:
-        diagnostics.append(f"Attestation signature status is not acceptable for this prototype: {signature_status}")
+    if public_key_path:
+        ok, error = verify_attestation_signature(raw, public_key_path)
+        if ok:
+            signature_status = "verified"
+        else:
+            diagnostics.append(f"Attestation signature verification failed: {error}")
+    elif signature_status == "signed":
+        diagnostics.append("Signed attestation requires --attestation-public-key.")
+    elif signature_status == "not_implemented":
+        if allow_unsigned:
+            signature_status = "not_implemented"
+        else:
+            diagnostics.append("Unsigned attestation requires --allow-unsigned-attestation.")
+    elif signature_status != "verified":
+        diagnostics.append(f"Attestation signature status is not acceptable: {signature_status}")
 
     accepted = not diagnostics
     evidence = {
@@ -72,6 +88,8 @@ def validate_attestation(
         "attestation_signature_status": signature_status,
         "attestation_log_url": raw.get("log_url") or signature.get("log_url"),
         "attestation_issued_at": raw.get("issued_at"),
+        "check_log_path": (raw.get("replay") or {}).get("check_log_path"),
+        "axiom_log_path": (raw.get("replay") or {}).get("axiom_log_path"),
         "lean_version": environment.get("lean_version"),
         "lake_version": environment.get("lake_version"),
     }

src/pacta/claims.py

@@ -45,6 +45,7 @@ def build_claim_card(
     tools = detect_tools()
     certs = _certificate_claims(repo, axiom_audit, offline_fixture, attestation)
     scanned_files = layout.relative_files() if layout else []
+    attestation_evidence = attestation.evidence if attestation else {}
     card: dict[str, Any] = {
         "component": repo.name,
         "repo_url": repo.url,
@@ -59,13 +60,13 @@ def build_claim_card(
         "exclusions": profile.exclusions,
         "trusted_base": [*profile.trusted_base, *(attestation.trusted_base if attestation and attestation.accepted else [])],
         "evidence": {
-            "lean_version": tools.lean_version,
-            "lake_version": tools.lake_version,
-            "check_log_path": lean_check.log_path if lean_check else None,
-            "axiom_log_path": axiom_audit.log_path if axiom_audit else None,
+            "lean_version": attestation_evidence.get("lean_version") or tools.lean_version,
+            "lake_version": attestation_evidence.get("lake_version") or tools.lake_version,
+            "check_log_path": attestation_evidence.get("check_log_path") or (lean_check.log_path if lean_check else None),
+            "axiom_log_path": attestation_evidence.get("axiom_log_path") or (axiom_audit.log_path if axiom_audit else None),
             "replay_blockers": _replay_blockers(lean_check, axiom_audit, attestation),
             "scanned_files": scanned_files,
-            **(attestation.evidence if attestation else {"evidence_mode": "local_or_fixture"}),
+            **(attestation_evidence if attestation else {"evidence_mode": "local_or_fixture"}),
         },
         "risk": {
             "level": "R0",

src/pacta/cli.py

@@ -104,6 +104,8 @@ def build_parser() -> argparse.ArgumentParser:
     claims.add_argument("--lean-project-dir")
     claims.add_argument("--attestation")
     claims.add_argument("--trust-attestation-provider")
+    claims.add_argument("--attestation-public-key")
+    claims.add_argument("--allow-unsigned-attestation", action="store_true")
     claims.set_defaults(func=cmd_claims)
 
     report = sub.add_parser("report", help="Generate a human-readable Markdown risk report.")
@@ -139,6 +141,8 @@ def build_parser() -> argparse.ArgumentParser:
     agent.add_argument("--lean-project-dir")
     agent.add_argument("--attestation")
     agent.add_argument("--trust-attestation-provider")
+    agent.add_argument("--attestation-public-key")
+    agent.add_argument("--allow-unsigned-attestation", action="store_true")
     agent.set_defaults(func=cmd_agent)
     return parser
 
@@ -445,4 +449,11 @@ def _attestation_for_args(args: argparse.Namespace, repo: RepoConfig):
     if not attestation_path:
         return None
     raw = load_attestation(attestation_path)
-    return validate_attestation(raw, repo, path=attestation_path, trusted_provider=getattr(args, "trust_attestation_provider", None))
+    return validate_attestation(
+        raw,
+        repo,
+        path=attestation_path,
+        trusted_provider=getattr(args, "trust_attestation_provider", None),
+        public_key_path=getattr(args, "attestation_public_key", None),
+        allow_unsigned=bool(getattr(args, "allow_unsigned_attestation", False)),
+    )

src/pacta/lean.py

@@ -98,8 +98,11 @@ def build_lean_invocation(
     tools: LeanTools,
     use_lake_env: bool = False,
     output_path: str | Path | None = None,
+    root_path: str | Path | None = None,
 ) -> list[str]:
     args = ["lean"]
+    if root_path is not None:
+        args.append(f"--root={root_path}")
     if output_path is not None:
         args.extend(["-o", str(output_path)])
     args.append(str(file_path))
@@ -163,7 +166,13 @@ def lean_check_files(
         log.write(f"env_script: {env_script or ''}\n")
         log.write(f"lean_project_dir: {project_dir or ''}\n\n")
         for path in files:
-            cmd = build_lean_invocation(path, tools, use_lake_env=use_lake_env, output_path=path.with_suffix(".olean"))
+            cmd = build_lean_invocation(
+                path,
+                tools,
+                use_lake_env=use_lake_env,
+                output_path=path.with_suffix(".olean"),
+                root_path=_lean_root_for_file(path, verification),
+            )
             log.write("$ " + " ".join(cmd) + "\n")
             try:
                 completed = subprocess.run(
@@ -326,6 +335,15 @@ def _log_file(log_dir: str | Path | None, name: str) -> Path:
     return directory / name
 
 
+def _lean_root_for_file(path: Path, verification_dir: Path) -> Path:
+    gen_dir = verification_dir / "gen"
+    try:
+        path.relative_to(gen_dir)
+        return gen_dir
+    except ValueError:
+        return verification_dir
+
+
 def _base_env(base_env: dict[str, str] | None, env_script: str | Path | None) -> dict[str, str]:
     env = dict(base_env or os.environ)
     if not env_script:
@@ -336,7 +354,7 @@ def _base_env(base_env: dict[str, str] | None, env_script: str | Path | None) ->
     command = f"source {shlex.quote(str(path))}; env"
     try:
         completed = subprocess.run(
-            ["/bin/zsh", "-lc", command],
+            ["/bin/bash", "-lc", command],
             check=False,
             capture_output=True,
             text=True,

src/pacta/signing.py

@@ -0,0 +1,124 @@
+from __future__ import annotations
+
+import base64
+import hashlib
+import json
+import shutil
+import subprocess
+import tempfile
+from pathlib import Path
+from typing import Any
+
+
+class SignatureError(RuntimeError):
+    pass
+
+
+def canonical_attestation_payload(attestation: dict[str, Any]) -> bytes:
+    unsigned = {key: value for key, value in attestation.items() if key != "signature"}
+    return json.dumps(unsigned, sort_keys=True, separators=(",", ":"), ensure_ascii=False).encode("utf-8")
+
+
+def payload_digest(attestation: dict[str, Any]) -> str:
+    return hashlib.sha256(canonical_attestation_payload(attestation)).hexdigest()
+
+
+def public_key_fingerprint(public_key_path: str | Path) -> str:
+    data = Path(public_key_path).read_bytes()
+    return hashlib.sha256(data).hexdigest()
+
+
+def generate_ed25519_keypair(private_key_path: str | Path, public_key_path: str | Path) -> None:
+    openssl = _openssl()
+    private_path = Path(private_key_path)
+    public_path = Path(public_key_path)
+    private_path.parent.mkdir(parents=True, exist_ok=True)
+    public_path.parent.mkdir(parents=True, exist_ok=True)
+    subprocess.run([openssl, "genpkey", "-algorithm", "ed25519", "-out", str(private_path)], check=True, timeout=30)
+    subprocess.run([openssl, "pkey", "-in", str(private_path), "-pubout", "-out", str(public_path)], check=True, timeout=30)
+
+
+def sign_attestation(attestation: dict[str, Any], private_key_path: str | Path, public_key_path: str | Path | None = None) -> dict[str, Any]:
+    openssl = _openssl()
+    payload = canonical_attestation_payload(attestation)
+    with tempfile.TemporaryDirectory(prefix="pacta-sign-") as tmp:
+        payload_path = Path(tmp) / "payload.json"
+        signature_path = Path(tmp) / "payload.sig"
+        payload_path.write_bytes(payload)
+        completed = subprocess.run(
+            [openssl, "pkeyutl", "-sign", "-inkey", str(private_key_path), "-rawin", "-in", str(payload_path), "-out", str(signature_path)],
+            check=False,
+            capture_output=True,
+            text=True,
+            timeout=30,
+        )
+        if completed.returncode != 0:
+            raise SignatureError((completed.stderr or completed.stdout or "openssl signing failed").strip())
+        signature_bytes = signature_path.read_bytes()
+    signed = dict(attestation)
+    signed["signature"] = {
+        "scheme": "openssl-ed25519",
+        "status": "signed",
+        "payload_digest_sha256": hashlib.sha256(payload).hexdigest(),
+        "signature_base64": base64.b64encode(signature_bytes).decode("ascii"),
+    }
+    if public_key_path:
+        signed["signature"]["public_key_fingerprint_sha256"] = public_key_fingerprint(public_key_path)
+    return signed
+
+
+def verify_attestation_signature(attestation: dict[str, Any], public_key_path: str | Path) -> tuple[bool, str | None]:
+    openssl = _openssl()
+    signature = attestation.get("signature") or {}
+    if signature.get("scheme") != "openssl-ed25519":
+        return False, f"Unsupported attestation signature scheme: {signature.get('scheme')}"
+    encoded = signature.get("signature_base64")
+    if not encoded:
+        return False, "Attestation signature is missing signature_base64."
+    expected_digest = signature.get("payload_digest_sha256")
+    actual_digest = payload_digest(attestation)
+    if expected_digest and expected_digest != actual_digest:
+        return False, "Attestation payload digest does not match signature metadata."
+    expected_fingerprint = signature.get("public_key_fingerprint_sha256")
+    if expected_fingerprint:
+        actual_fingerprint = public_key_fingerprint(public_key_path)
+        if expected_fingerprint != actual_fingerprint:
+            return False, "Attestation public key fingerprint does not match signature metadata."
+    try:
+        signature_bytes = base64.b64decode(encoded, validate=True)
+    except ValueError as exc:
+        return False, f"Invalid base64 signature: {exc}"
+    with tempfile.TemporaryDirectory(prefix="pacta-verify-") as tmp:
+        payload_path = Path(tmp) / "payload.json"
+        signature_path = Path(tmp) / "payload.sig"
+        payload_path.write_bytes(canonical_attestation_payload(attestation))
+        signature_path.write_bytes(signature_bytes)
+        completed = subprocess.run(
+            [
+                openssl,
+                "pkeyutl",
+                "-verify",
+                "-pubin",
+                "-inkey",
+                str(public_key_path),
+                "-rawin",
+                "-in",
+                str(payload_path),
+                "-sigfile",
+                str(signature_path),
+            ],
+            check=False,
+            capture_output=True,
+            text=True,
+            timeout=30,
+        )
+    if completed.returncode != 0:
+        return False, (completed.stderr or completed.stdout or "openssl verification failed").strip()
+    return True, None
+
+
+def _openssl() -> str:
+    path = shutil.which("openssl")
+    if not path:
+        raise SignatureError("openssl is not available on PATH")
+    return path

tests/test_attestation.py

@@ -1,6 +1,7 @@
 from pacta.attestation import load_attestation, validate_attestation
 from pacta.claims import build_claim_card
 from pacta.config import RepoConfig
+from pacta.signing import generate_ed25519_keypair, sign_attestation
 
 
 def _repo():
@@ -15,7 +16,13 @@ def _repo():
 
 def test_trusted_attestation_can_drive_r3_claim(tmp_path):
     raw = load_attestation("examples/dalek-ed25519.attestation.yaml")
-    result = validate_attestation(raw, _repo(), path="examples/dalek-ed25519.attestation.yaml", trusted_provider="example-proof-checker.invalid")
+    result = validate_attestation(
+        raw,
+        _repo(),
+        path="examples/dalek-ed25519.attestation.yaml",
+        trusted_provider="example-proof-checker.invalid",
+        allow_unsigned=True,
+    )
     card = build_claim_card(_repo(), tmp_path, attestation=result)
     assert result.accepted
     assert card["risk"]["level"] == "R3"
@@ -30,3 +37,18 @@ def test_untrusted_attestation_scores_r0(tmp_path):
     card = build_claim_card(_repo(), tmp_path, attestation=result)
     assert not result.accepted
     assert card["risk"]["level"] == "R0"
+
+
+def test_signed_attestation_requires_public_key(tmp_path):
+    private_key = tmp_path / "provider.key"
+    public_key = tmp_path / "provider.pub"
+    generate_ed25519_keypair(private_key, public_key)
+    raw = load_attestation("examples/dalek-ed25519.attestation.yaml")
+    raw["provider"] = "signed-test-provider"
+    raw["signature"] = {}
+    signed = sign_attestation(raw, private_key, public_key)
+    result = validate_attestation(signed, _repo(), trusted_provider="signed-test-provider")
+    card = build_claim_card(_repo(), tmp_path, attestation=result)
+    assert not result.accepted
+    assert card["risk"]["level"] == "R0"
+    assert any("attestation-public-key" in item for item in result.diagnostics)

tests/test_lean.py

@@ -26,8 +26,8 @@ def test_parse_axiom_output_no_axioms_wording():
 
 def test_mac_safe_lean_command_is_argument_list():
     tools = LeanTools(lean="/usr/local/bin/lean", lake=None)
-    cmd = build_lean_invocation(Path("Proofs/A.lean"), tools, output_path=Path("Proofs/A.olean"))
-    assert cmd == ["/usr/local/bin/lean", "-o", "Proofs/A.olean", "Proofs/A.lean"]
+    cmd = build_lean_invocation(Path("Proofs/A.lean"), tools, output_path=Path("Proofs/A.olean"), root_path=Path("."))
+    assert cmd == ["/usr/local/bin/lean", "--root=.", "-o", "Proofs/A.olean", "Proofs/A.lean"]
     assert "timeout" not in cmd
     assert "taskset" not in cmd
     assert "free" not in cmd

tests/test_provider.py

@@ -0,0 +1,50 @@
+from pathlib import Path
+import sys
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "provider" / "src"))
+
+from pacta.config import RepoConfig
+from pacta.signing import generate_ed25519_keypair
+from pacta_provider.discovery import discover_toolchains
+from pacta_provider.service import build_attestation
+
+
+def test_provider_discovery_finds_env_script(tmp_path):
+    root = tmp_path / "toolchains" / "aeneas-toolchain"
+    lean = root / "aeneas" / "backends" / "lean"
+    lean.mkdir(parents=True)
+    (lean / "lakefile.lean").write_text("", encoding="utf-8")
+    (root / "env.sh").write_text(
+        'SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"\n'
+        'export AENEAS_HOME="$SCRIPT_DIR/aeneas"\n',
+        encoding="utf-8",
+    )
+    candidates = discover_toolchains([tmp_path], max_depth=5)
+    assert candidates
+    assert candidates[0].lean_project_dir == lean
+
+
+def test_provider_builds_signed_attestation_for_fixture(tmp_path):
+    private_key = tmp_path / "provider.key"
+    public_key = tmp_path / "provider.pub"
+    generate_ed25519_keypair(private_key, public_key)
+    repo = RepoConfig(
+        name="dalek-ed25519-verified",
+        url="https://github.com/saymrwulf/dalek-ed25519-verified.git",
+        kind="ed25519",
+        verification_dir="verification",
+        verified_backend="serial/u64",
+        certificates=["CurveFieldProofs.fieldImplementation", "CurveFieldProofs.edwardsImplementation"],
+        expected_axioms=[],
+    )
+    attestation = build_attestation(
+        repo,
+        Path("tests/fixtures/mini-ed25519-verified"),
+        provider="local-test-provider",
+        private_key=private_key,
+        public_key=public_key,
+        timeout=30,
+        log_dir=tmp_path / "logs",
+    )
+    assert attestation["signature"]["status"] == "signed"
+    assert attestation["certificates"][0]["status"] == "proven"

tests/test_signing.py

@@ -0,0 +1,20 @@
+from pacta.signing import generate_ed25519_keypair, sign_attestation, verify_attestation_signature
+
+
+def test_openssl_ed25519_attestation_signature_round_trip(tmp_path):
+    private_key = tmp_path / "provider.key"
+    public_key = tmp_path / "provider.pub"
+    generate_ed25519_keypair(private_key, public_key)
+    attestation = {
+        "schema_version": 1,
+        "provider": "local-test-provider",
+        "subject": {"component": "mini"},
+        "certificates": [],
+    }
+    signed = sign_attestation(attestation, private_key, public_key)
+    ok, error = verify_attestation_signature(signed, public_key)
+    assert ok, error
+    signed["subject"]["component"] = "tampered"
+    ok, error = verify_attestation_signature(signed, public_key)
+    assert not ok
+    assert error