diff --git a/.github/workflows/validate.yml b/.github/workflows/validate.yml
index 97a0c4b..b6f00d2 100644
--- a/.github/workflows/validate.yml
+++ b/.github/workflows/validate.yml
@@ -20,8 +20,18 @@ jobs:
         uses: ruby/setup-ruby@v1
         with:
           ruby-version: '3.3'
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+      - name: Install Python validator dependencies
+        run: python3 -m pip install -r requirements-dev.txt
       - name: Validate skill format and links
         run: ruby scripts/validate-skills.rb
+      - name: Test eval manifest validation
+        run: python3 scripts/test-eval-validation.py
+      - name: Validate eval manifests
+        run: python3 scripts/validate-evals.py
       - name: Test changed-skill quality validation
         run: ruby scripts/test-validate-skill-quality.rb
       - name: Validate changed skill quality
diff --git a/AGENTS.md b/AGENTS.md
index 93ae4c9..6d9435c 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -97,9 +97,31 @@ Every skill description must start with an imperative verb and define both when
 
 ## Eval Requirements
 
-Every new skill must include `evals/evals.json` with at least five representative output-quality cases. Each case needs a realistic prompt, an expected outcome, and observable assertions. Trigger-only checks (should-trigger / should-not-trigger probes) are harness-specific and belong in a separate test set, not in `evals/evals.json`.
+`evals/evals.json` is a versioned contract owned by this repository; it is not part of the normative Agent Skills specification. The declarative contract is [`schemas/evals-v1.schema.json`](schemas/evals-v1.schema.json), and `assertions` is the canonical case field. Do not substitute or alias `expectations`.
 
-Existing skills are grandfathered via `scripts/grandfathered-skills.txt`. As overall eval coverage climbs past 25%, modified skills without evals receive a warning; past 50%, they fail CI. The coverage report is available via `python3 scripts/eval-coverage.py`. The ratchet is enforced in CI via `python3 scripts/eval-coverage.py --modified-from <base-sha>` on every pull request. A skill is considered modified when any tracked file under its directory changes, not only `SKILL.md`. Coverage must not decrease between the base revision and the candidate; a decrease fails CI.
+Every new skill must include a schema-versioned `evals/evals.json` with at least five representative output-quality cases. Each case needs a stable ID, realistic prompt, expected outcome, and observable assertions. Renaming an eval ID breaks durable evidence references; do not attempt heuristic rename matching. Trigger-only checks (should-trigger / should-not-trigger probes) are harness-specific and belong in a separate test set, not in `evals/evals.json`.
+
+Coverage reports these five states separately:
+
+| State | Evidence required |
+|-------|-------------------|
+| `manifest_present` | `evals/evals.json` exists. This alone does not prove behavioral quality. |
+| `schema_valid` | The manifest passes the repository's v1 structural and semantic validation. |
+| `executable_grader_bindings_present` | Not assessed in v1. Requires a separate versioned grader-binding contract. |
+| `recent_run_evidence_present` | Not assessed in v1. Requires a separate versioned provenance/freshness contract. |
+| `release_gated_evidence_present` | Not assessed in v1. Requires a separate versioned release-gate contract. |
+
+v1 only covers manifest structure and semantic validity. It does not establish runtime provenance or release-gate evidence. Validate the contract and run its focused tests with:
+
+```sh
+python3 -m venv .venv
+. .venv/bin/activate
+python3 -m pip install -r requirements-dev.txt
+python3 scripts/test-eval-validation.py
+python3 scripts/validate-evals.py
+```
+
+Existing skills are grandfathered via `scripts/grandfathered-skills.txt`. As schema-valid manifest coverage climbs past 25%, modified skills without valid manifests receive a warning; past 50%, they fail CI. The coverage report is available via `python3 scripts/eval-coverage.py`. The ratchet is enforced in CI via `python3 scripts/eval-coverage.py --modified-from <base-sha>` on every pull request. A skill is considered modified when any tracked file under its directory changes, not only `SKILL.md`. Schema-valid manifest coverage must not decrease between the base revision and the candidate; a decrease fails CI.
 
 ## Best Practices
 
@@ -130,6 +152,7 @@ When creating or modifying a skill in this repo, validate against the format:
 - **`README.md` exists in the skill root** with all required sections (see [README Format](#readme-format) above)
 - **README is written for humans** — no agent instructions, JSON schemas, or progressive disclosure notes in the README. Those belong in `SKILL.md`.
 - **`evals/evals.json` exists** with at least five output-quality cases for new skills (see [Eval Requirements](#eval-requirements))
+- `python3 scripts/validate-evals.py` accepts every present eval manifest
 
 ### Generated Artifacts
 
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 9db1d31..3ef45ff 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -20,7 +20,9 @@ Each skill must:
 - Use relative links that work from a fresh clone.
 - Use an imperative-verb description that defines both positive and negative trigger boundaries.
 - Describe when the skill should be loaded, and identify the nearest alternative when overlap matters.
-- Include `evals/evals.json` with at least five representative output-quality cases for every new skill. Existing skills are grandfathered via `scripts/grandfathered-skills.txt`; the ratchet tightens as overall coverage climbs. The ratchet runs in CI on every pull request via `python3 scripts/eval-coverage.py --modified-from <base-sha>`. A skill counts as modified when any tracked file under its directory changes. Coverage must not decrease between the base revision and the candidate.
+- Include `evals/evals.json` with explicit `schema_version: 1` and at least five representative output-quality cases for every new skill. This is a repository-owned contract, not part of the normative Agent Skills specification; see [`schemas/evals-v1.schema.json`](schemas/evals-v1.schema.json). Use canonical `assertions`, not `expectations`. Existing skills are grandfathered via `scripts/grandfathered-skills.txt`; the ratchet tightens as schema-valid manifest coverage climbs. The ratchet runs in CI on every pull request via `python3 scripts/eval-coverage.py --modified-from <base-sha>`. A skill counts as modified when any tracked file under its directory changes. Schema-valid manifest coverage must not decrease between the base revision and the candidate.
+
+The coverage report keeps claims separate. `manifest_present` means only that a file exists. Per skill, `schema_valid` is `not_applicable` when `evals/evals.json` is missing, `false` when a present manifest fails parsing/schema/semantic validation, and `true` only when the manifest passes repository v1 validation. Aggregate schema-valid coverage counts only skills where `schema_valid` is `true`. The remaining states are named but intentionally `not_assessed` in v1: `executable_grader_bindings_present`, `recent_run_evidence_present`, and `release_gated_evidence_present`. Those require separate versioned contracts for grader bindings, provenance/freshness, and release-gate evidence.
 
 ## Development
 
@@ -29,8 +31,13 @@ Clone the repository and run the validators from its root:
 ```sh
 git clone https://github.com/magnus919/agent-skills.git
 cd agent-skills
+python3 -m venv .venv
+. .venv/bin/activate
+python3 -m pip install -r requirements-dev.txt
 ruby scripts/validate-skills.rb
 ruby scripts/validate-skill-quality.rb --base origin/main
+python3 scripts/test-eval-validation.py
+python3 scripts/validate-evals.py
 python3 scripts/test-eval-coverage.py
 python3 scripts/eval-coverage.py
 ```
diff --git a/de-spin/evals/evals.json b/de-spin/evals/evals.json
index 2a771ee..2f4fe21 100644
--- a/de-spin/evals/evals.json
+++ b/de-spin/evals/evals.json
@@ -1,4 +1,5 @@
 {
+  "schema_version": 1,
   "skill_name": "de-spin",
   "evals": [
     {
diff --git a/esp32-development/evals/evals.json b/esp32-development/evals/evals.json
index 1ad7049..7372cfc 100644
--- a/esp32-development/evals/evals.json
+++ b/esp32-development/evals/evals.json
@@ -1,4 +1,5 @@
 {
+  "schema_version": 1,
   "skill_name": "esp32-development",
   "evals": [
     {
diff --git a/raleigh/evals/evals.json b/raleigh/evals/evals.json
index f416ff7..71852c0 100644
--- a/raleigh/evals/evals.json
+++ b/raleigh/evals/evals.json
@@ -1,4 +1,5 @@
 {
+  "schema_version": 1,
   "skill_name": "raleigh",
   "evals": [
     {
diff --git a/requirements-dev.txt b/requirements-dev.txt
new file mode 100644
index 0000000..66cc01a
--- /dev/null
+++ b/requirements-dev.txt
@@ -0,0 +1,2 @@
+jsonschema[format]==4.26.0
+requests==2.34.2
diff --git a/restic/evals/evals.json b/restic/evals/evals.json
index d8bcbc9..f73f6b9 100644
--- a/restic/evals/evals.json
+++ b/restic/evals/evals.json
@@ -1,4 +1,5 @@
 {
+  "schema_version": 1,
   "skill_name": "restic",
   "evals": [
     {
diff --git a/schemas/evals-v1.schema.json b/schemas/evals-v1.schema.json
new file mode 100644
index 0000000..30cba2e
--- /dev/null
+++ b/schemas/evals-v1.schema.json
@@ -0,0 +1,50 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://github.com/magnus919/agent-skills/schemas/evals-v1.schema.json",
+  "title": "agent-skills repository eval manifest v1",
+  "type": "object",
+  "additionalProperties": false,
+  "required": ["schema_version", "skill_name", "evals"],
+  "properties": {
+    "schema_version": {"type": "integer", "const": 1},
+    "skill_name": {"type": "string", "minLength": 1, "pattern": "\\S"},
+    "evals": {
+      "type": "array",
+      "minItems": 1,
+      "items": {"$ref": "#/$defs/eval_case"}
+    }
+  },
+  "$defs": {
+    "relative_path": {
+      "type": "string",
+      "minLength": 1,
+      "pattern": "^(?=.*\\S)(?!/)(?!\\./)(?!.*//)(?!.*(?:^|/)\\.(?:/|$))(?!.*(?:^|/)\\.\\.(?:/|$))(?!.*\\\\)(?!.*\\/$).+$"
+    },
+    "eval_case": {
+      "type": "object",
+      "additionalProperties": false,
+      "required": ["id", "prompt", "expected_output", "assertions"],
+      "properties": {
+        "id": {
+          "type": "string",
+          "minLength": 1,
+          "maxLength": 64,
+          "pattern": "^[a-z0-9]+(?:-[a-z0-9]+)*$"
+        },
+        "prompt": {"type": "string", "minLength": 1, "pattern": "\\S"},
+        "expected_output": {"type": "string", "minLength": 1, "pattern": "\\S"},
+        "assertions": {
+          "type": "array",
+          "minItems": 1,
+          "uniqueItems": true,
+          "items": {"type": "string", "minLength": 1, "pattern": "\\S"}
+        },
+        "files": {
+          "type": "array",
+          "uniqueItems": true,
+          "items": {"$ref": "#/$defs/relative_path"}
+        }
+      }
+    }
+  }
+}
diff --git a/scripts/eval-coverage.py b/scripts/eval-coverage.py
index a960715..a965b0c 100644
--- a/scripts/eval-coverage.py
+++ b/scripts/eval-coverage.py
@@ -11,13 +11,17 @@ Usage:
 """
 
 import argparse
+import io
 import json
 import subprocess
 import sys
+import tarfile
+import tempfile
 from pathlib import Path
 
+from eval_validation import NOT_ASSESSED, STATE_NAMES, ValidationResult, validate_manifest
+
 ROOT = Path(__file__).resolve().parent.parent
-GRANDFATHER_FILE = ROOT / "scripts" / "grandfathered-skills.txt"
 
 # Phase 3 ratchet thresholds (percent of skills with evals)
 WARN_THRESHOLD = 25   # modified skills without evals get a warning
@@ -48,10 +52,28 @@ def find_skills() -> list[Path]:
     return sorted(skills)
 
 
+def resolve_ref_to_commit(ref: str) -> str:
+    """Resolve *ref* to a commit SHA or raise ValueError.
+
+    The caller must use only the returned SHA in subsequent git commands.
+    """
+    result = subprocess.run(
+        ["git", "rev-parse", "--verify", "--end-of-options", f"{ref}^{{commit}}"],
+        cwd=ROOT,
+        capture_output=True,
+        text=True,
+    )
+    if result.returncode != 0:
+        raise ValueError(
+            f"invalid --modified-from ref: {ref!r} is not an existing commit"
+        )
+    return result.stdout.strip()
+
+
 def find_skills_at(ref: str) -> list[Path]:
     """Find canonical skill directories tracked at a git revision."""
     result = subprocess.run(
-        ["git", "ls-tree", "-r", "--name-only", ref],
+        ["git", "ls-tree", "-r", "--name-only", ref, "--"],
         cwd=ROOT,
         check=True,
         capture_output=True,
@@ -66,30 +88,16 @@ def find_skills_at(ref: str) -> list[Path]:
             skills.append(Path(name).parent)
     return sorted(skills)
 
-
-def load_grandfathered() -> set[str]:
-    if not GRANDFATHER_FILE.exists():
-        return set()
-    return {
-        line.strip()
-        for line in GRANDFATHER_FILE.read_text().splitlines()
-        if line.strip() and not line.strip().startswith("#")
-    }
+def check_eval_states(skill_dir: Path) -> ValidationResult:
+    """Return validation and evidence states for one skill."""
+    evals_file = ROOT / skill_dir / "evals" / "evals.json"
+    return validate_manifest(evals_file, ROOT)
 
 
 def check_evals(skill_dir: Path) -> tuple[bool, int]:
-    """Return (has_valid_evals, case_count) for a skill directory."""
-    evals_file = ROOT / skill_dir / "evals" / "evals.json"
-    if not evals_file.exists():
-        return False, 0
-    try:
-        data = json.loads(evals_file.read_text(encoding="utf-8"))
-        if isinstance(data, dict) and isinstance(data.get("evals"), list):
-            count = len(data["evals"])
-            return count > 0, count
-        return False, 0
-    except (json.JSONDecodeError, OSError):
-        return False, 0
+    """Return (has_schema_valid_manifest, case_count) for compatibility."""
+    result = check_eval_states(skill_dir)
+    return result.states["schema_valid"] is True, result.case_count
 
 
 def count_references(skill_name: str, all_skill_dirs: list[Path]) -> int:
@@ -107,7 +115,7 @@ def count_references(skill_name: str, all_skill_dirs: list[Path]) -> int:
     return count
 
 
-def modified_skills(base_ref: str) -> set[Path]:
+def modified_skills(base_ref_commit: str) -> set[Path]:
     """Return skill directories with any tracked file changed since base_ref.
 
     A skill is considered modified when *any* file under its directory
@@ -115,7 +123,7 @@ def modified_skills(base_ref: str) -> set[Path]:
     fixtures, README, and eval manifests.
     """
     result = subprocess.run(
-        ["git", "diff", "--name-only", base_ref, "HEAD"],
+        ["git", "diff", "--name-only", base_ref_commit, "HEAD", "--"],
         cwd=ROOT,
         capture_output=True,
         text=True,
@@ -129,7 +137,7 @@ def modified_skills(base_ref: str) -> set[Path]:
     # Include skills from both revisions so complete directory deletions
     # remain observable under their old name.
     known_skills = sorted(
-        set(find_skills()) | set(find_skills_at(base_ref)),
+        set(find_skills()) | set(find_skills_at(base_ref_commit)),
         key=lambda path: len(path.parts),
         reverse=True,
     )
@@ -159,62 +167,50 @@ def evaluate_ratchet(
         name = str(skill_dir)
         if coverage_pct >= FAIL_THRESHOLD:
             errors.append(
-                f"{name}: modified skill has no evals "
+                f"{name}: modified skill has no schema-valid eval manifest "
                 f"(coverage {coverage_pct:.1f}% >= {FAIL_THRESHOLD}% — "
                 "evals required on modification)"
             )
         elif coverage_pct >= WARN_THRESHOLD:
             warnings.append(
-                f"{name}: modified skill has no evals "
+                f"{name}: modified skill has no schema-valid eval manifest "
                 f"(coverage {coverage_pct:.1f}% >= {WARN_THRESHOLD}% — "
                 "evals recommended)"
             )
     return warnings, errors
 
 
-def coverage_decreased(base_ref: str) -> tuple[bool, float, float]:
+def coverage_decreased(base_ref_commit: str) -> tuple[bool, float, float]:
     """Compare eval coverage between base_ref and HEAD.
 
     Returns (decreased, base_pct, head_pct).  Coverage is the percentage
-    of canonical skills that have a non-empty evals/evals.json.
+    of canonical skills that have a schema-valid v1 evals/evals.json.
     """
     head_skills = find_skills()
     head_with = sum(1 for s in head_skills if check_evals(s)[0])
     head_pct = (head_with / len(head_skills) * 100) if head_skills else 0.0
 
-    # Count skills with evals at the base revision.
-    result = subprocess.run(
-        ["git", "ls-tree", "-r", "--name-only", base_ref],
-        cwd=ROOT,
-        capture_output=True,
-        text=True,
-    )
-    base_skill_dirs: set[Path] = set()
-    for line in result.stdout.strip().splitlines():
-        if (
-            line
-            and line.endswith("/SKILL.md")
-            and "/agent-council/profiles/skills/" not in line
-        ):
-            base_skill_dirs.add(Path(line).parent)
-
+    base_skill_dirs = set(find_skills_at(base_ref_commit))
     base_with = 0
-    for skill_dir in base_skill_dirs:
-        evals_path = f"{skill_dir}/evals/evals.json"
-        cat = subprocess.run(
-            ["git", "show", f"{base_ref}:{evals_path}"],
-            cwd=ROOT,
+    archive = subprocess.run(
+        ["git", "archive", "--format=tar", base_ref_commit, "--"],
+        cwd=ROOT,
+        check=True,
+        capture_output=True,
+    ).stdout
+    with tempfile.TemporaryDirectory() as tmp:
+        snapshot = Path(tmp)
+        with tarfile.open(fileobj=io.BytesIO(archive), mode="r:") as tar:
+            tar.extractall(snapshot, filter="data")
+        subprocess.run(["git", "init", "-q"], cwd=snapshot, check=True)
+        subprocess.run(
+            ["git", "add", "-f", "--all"], cwd=snapshot, check=True,
             capture_output=True,
-            text=True,
         )
-        if cat.returncode != 0:
-            continue
-        try:
-            data = json.loads(cat.stdout)
-            if isinstance(data, dict) and isinstance(data.get("evals"), list) and len(data["evals"]) > 0:
+        for skill_dir in base_skill_dirs:
+            manifest = snapshot / skill_dir / "evals" / "evals.json"
+            if validate_manifest(manifest, snapshot).states["schema_valid"] is True:
                 base_with += 1
-        except (json.JSONDecodeError, ValueError):
-            pass
 
     base_pct = (base_with / len(base_skill_dirs) * 100) if base_skill_dirs else 0.0
     return head_pct < base_pct, base_pct, head_pct
@@ -230,22 +226,54 @@ def main() -> int:
     )
     args = parser.parse_args()
 
+    resolved_base_ref = None
+    if args.modified_from:
+        try:
+            resolved_base_ref = resolve_ref_to_commit(args.modified_from)
+        except ValueError as exc:
+            print(f"ERROR: {exc}", file=sys.stderr)
+            return 2
+
     skills = find_skills()
-    grandfathered = load_grandfathered()
 
     total = len(skills)
-    with_evals: list[dict] = []
+    skill_states: list[dict] = []
     without_evals: list[str] = []
 
     for skill_dir in skills:
-        has, count = check_evals(skill_dir)
+        validation = check_eval_states(skill_dir)
+        has = validation.states["schema_valid"]
+        count = validation.case_count
         name = str(skill_dir)
-        if has:
-            with_evals.append({"skill": name, "cases": count})
-        else:
+        skill_states.append({"skill": name, "cases": count, **validation.states})
+        if has is not True:
             without_evals.append(name)
 
-    coverage_pct = (len(with_evals) / total * 100) if total else 0.0
+    supported_states = ("manifest_present", "schema_valid")
+    state_summary: dict[str, dict[str, object]] = {}
+    for state in supported_states:
+        count = sum(1 for entry in skill_states if entry[state] is True)
+        state_summary[state] = {
+            "assessment": "supported",
+            "count": count,
+            "percentage": round((count / total * 100) if total else 0.0, 1),
+        }
+
+    not_assessed_reasons = {
+        "executable_grader_bindings_present": "No repository contract for executable grader bindings in schema v1.",
+        "recent_run_evidence_present": "No versioned provenance/freshness contract is defined for schema v1.",
+        "release_gated_evidence_present": "No versioned release-gate contract is defined for schema v1.",
+    }
+    for state in STATE_NAMES:
+        if state in state_summary:
+            continue
+        state_summary[state] = {
+            "assessment": NOT_ASSESSED,
+            "count": None,
+            "percentage": None,
+            "reason": not_assessed_reasons[state],
+        }
+    coverage_pct = state_summary["schema_valid"]["percentage"]
 
     # Sort skills without evals: most-referenced first, then alphabetical
     ref_counts = {
@@ -256,8 +284,8 @@ def main() -> int:
     # Phase 3 ratchet check
     ratchet_warnings: list[str] = []
     ratchet_errors: list[str] = []
-    if args.modified_from:
-        modified = modified_skills(args.modified_from)
+    if resolved_base_ref:
+        modified = modified_skills(resolved_base_ref)
         ratchet_warnings, ratchet_errors = evaluate_ratchet(
             modified=modified,
             current=set(skills),
@@ -266,7 +294,7 @@ def main() -> int:
         )
 
         # Monotonic coverage floor: fail if coverage decreased.
-        decreased, base_pct, head_pct = coverage_decreased(args.modified_from)
+        decreased, base_pct, head_pct = coverage_decreased(resolved_base_ref)
         if decreased:
             ratchet_errors.append(
                 f"eval coverage decreased from {base_pct:.1f}% to {head_pct:.1f}% "
@@ -278,14 +306,8 @@ def main() -> int:
             json.dumps(
                 {
                     "total_skills": total,
-                    "skills_with_evals": len(with_evals),
-                    "skills_without_evals": len(without_evals),
-                    "coverage_pct": round(coverage_pct, 1),
-                    "with_evals": with_evals,
-                    "without_evals": [
-                        {"skill": n, "references": ref_counts.get(n, 0)}
-                        for n in without_evals
-                    ],
+                    "states": state_summary,
+                    "skills": skill_states,
                     "ratchet": {
                         "warn_threshold": WARN_THRESHOLD,
                         "fail_threshold": FAIL_THRESHOLD,
@@ -297,14 +319,18 @@ def main() -> int:
             )
         )
     else:
-        print(f"Eval coverage: {len(with_evals)}/{total} skills ({coverage_pct:.1f}%)")
+        print("Eval evidence states (a manifest alone does not prove behavioral quality):")
+        for state in STATE_NAMES:
+            summary = state_summary[state]
+            if summary["assessment"] == "supported":
+                print(
+                    f"  {state}: {summary['count']}/{total} skills "
+                    f"({summary['percentage']:.1f}%)"
+                )
+                continue
+            print(f"  {state}: not assessed ({summary['reason']})")
         print()
-        if with_evals:
-            print("Skills WITH evals:")
-            for entry in with_evals:
-                print(f"  + {entry['skill']} ({entry['cases']} cases)")
-            print()
-        print(f"Skills WITHOUT evals ({len(without_evals)}), by reference count:")
+        print(f"Skills WITHOUT schema-valid eval manifests ({len(without_evals)}), by reference count:")
         for name in without_evals:
             refs = ref_counts.get(name, 0)
             print(f"  - {name} (referenced by {refs} skills)")
diff --git a/scripts/eval_validation.py b/scripts/eval_validation.py
new file mode 100644
index 0000000..b4d0b1e
--- /dev/null
+++ b/scripts/eval_validation.py
@@ -0,0 +1,364 @@
+#!/usr/bin/env python3
+"""Validation for this repository's eval manifest v1 contract."""
+
+from __future__ import annotations
+
+import json
+import re
+import subprocess
+from dataclasses import dataclass, field
+from functools import lru_cache
+from pathlib import Path, PurePosixPath
+from typing import Any
+
+from jsonschema import Draft202012Validator
+
+SCHEMA_VERSION = 1
+STATE_NAMES = (
+    "manifest_present",
+    "schema_valid",
+    "executable_grader_bindings_present",
+    "recent_run_evidence_present",
+    "release_gated_evidence_present",
+)
+NOT_ASSESSED = "not_assessed"
+NOT_APPLICABLE = "not_applicable"
+SCHEMA_PATH = Path(__file__).resolve().parent.parent / "schemas" / "evals-v1.schema.json"
+CASE_ID_RE = re.compile(r"^[a-z0-9]+(?:-[a-z0-9]+)*$")
+
+
+@dataclass
+class ValidationResult:
+    manifest_path: Path
+    case_count: int = 0
+    errors: list[str] = field(default_factory=list)
+    states: dict[str, bool | str] = field(
+        default_factory=lambda: {
+            "manifest_present": False,
+            "schema_valid": NOT_APPLICABLE,
+            "executable_grader_bindings_present": NOT_ASSESSED,
+            "recent_run_evidence_present": NOT_ASSESSED,
+            "release_gated_evidence_present": NOT_ASSESSED,
+        }
+    )
+
+    def error(self, location: str, message: str) -> None:
+        suffix = f" {location}" if location else ""
+        self.errors.append(f"{self.manifest_path}:{suffix}: {message}")
+
+
+class DuplicateKeyError(ValueError):
+    def __init__(self, key: str):
+        super().__init__(f"duplicate key {key!r}")
+        self.key = key
+
+
+def _reject_duplicate_keys(pairs: list[tuple[str, Any]]) -> dict[str, Any]:
+    out: dict[str, Any] = {}
+    for key, value in pairs:
+        if key in out:
+            raise DuplicateKeyError(key)
+        out[key] = value
+    return out
+
+
+def _json_pointer(path: Any) -> str:
+    if not path:
+        return "$"
+    location = "$"
+    for part in path:
+        location += f"[{part}]" if isinstance(part, int) else f".{part}"
+    return location
+
+
+def _nonempty_string(value: Any) -> bool:
+    return isinstance(value, str) and bool(value.strip())
+
+
+def _contains_control_characters(value: str) -> bool:
+    return any(ord(char) < 32 or ord(char) == 127 for char in value)
+
+
+def _git(repo_root: Path, *args: str) -> subprocess.CompletedProcess[bytes]:
+    return subprocess.run(["git", *args], cwd=repo_root, capture_output=True, check=False)
+
+
+def _tracked_files(repo_root: Path) -> set[str]:
+    result = _git(repo_root, "ls-files", "-z")
+    if result.returncode != 0:
+        return set()
+    return {
+        path
+        for path in result.stdout.decode("utf-8", errors="replace").split("\0")
+        if path
+    }
+
+
+def _tracked_mode(repo_root: Path, relative_path: str) -> str | None:
+    result = _git(repo_root, "ls-files", "-s", "--", relative_path)
+    if result.returncode != 0 or not result.stdout:
+        return None
+    return result.stdout.decode("utf-8", errors="replace").split(None, 1)[0]
+
+
+def _case_mismatch(tracked: set[str], relative_path: str) -> bool:
+    lower = relative_path.lower()
+    return any(path.lower() == lower and path != relative_path for path in tracked)
+
+
+def _load_json_strict(path: Path) -> dict[str, Any]:
+    text = path.read_text(encoding="utf-8")
+    parsed = json.loads(text, object_pairs_hook=_reject_duplicate_keys)
+    if not isinstance(parsed, dict):
+        raise TypeError("top-level JSON value must be an object")
+    return parsed
+
+
+@lru_cache(maxsize=1)
+def _schema_validator() -> Draft202012Validator:
+    schema = json.loads(SCHEMA_PATH.read_text(encoding="utf-8"))
+    Draft202012Validator.check_schema(schema)
+    return Draft202012Validator(schema)
+
+
+def _validate_schema(data: dict[str, Any], result: ValidationResult) -> None:
+    validator = _schema_validator()
+    for issue in sorted(validator.iter_errors(data), key=lambda e: list(e.path)):
+        result.error(_json_pointer(issue.absolute_path), issue.message)
+
+
+def _targeted_schema_version_errors(data: dict[str, Any], result: ValidationResult) -> None:
+    if "schema_version" not in data:
+        result.error(
+            "$.schema_version",
+            "missing required schema_version; add \"schema_version\": 1",
+        )
+        return
+    version = data["schema_version"]
+    if isinstance(version, str):
+        result.error(
+            "$.schema_version",
+            "schema_version must be integer 1, not a string",
+        )
+        return
+    if isinstance(version, bool) or not isinstance(version, int):
+        result.error("$.schema_version", "schema_version must be integer 1")
+        return
+    if version != SCHEMA_VERSION:
+        result.error(
+            "$.schema_version",
+            f"unsupported schema_version {version!r}; supported version is 1",
+        )
+
+
+def _validate_case_aliases(case: dict[str, Any], index: int, result: ValidationResult) -> None:
+    has_assertions = "assertions" in case
+    has_expectations = "expectations" in case
+    if has_assertions and has_expectations:
+        result.error(
+            f"$.evals[{index}].expectations",
+            "assertions and expectations cannot both be present; keep assertions only",
+        )
+    elif has_expectations:
+        result.error(
+            f"$.evals[{index}].expectations",
+            "expectations is not supported by repository schema v1; rename it to assertions",
+        )
+
+
+def _validate_fixture_path(
+    value: Any,
+    *,
+    skill_root: Path,
+    repo_root: Path,
+    tracked: set[str],
+    location: str,
+    result: ValidationResult,
+) -> None:
+    if not _nonempty_string(value):
+        result.error(location, "must be a nonempty relative path string")
+        return
+
+    path_text = value
+    if _contains_control_characters(path_text):
+        result.error(location, "must not contain control characters")
+        return
+    if "\\" in path_text:
+        result.error(location, "must not contain backslashes")
+        return
+
+    lexical_parts = path_text.split("/")
+    if any(part in {"", ".", ".."} for part in lexical_parts):
+        result.error(location, "must not contain '.', '..', or empty path components")
+        return
+
+    pure = PurePosixPath(path_text)
+    if pure.is_absolute() or not pure.parts:
+        result.error(location, "must be a relative path")
+        return
+
+    candidate = skill_root.joinpath(*lexical_parts)
+    relative = candidate.relative_to(repo_root).as_posix()
+
+    if _case_mismatch(tracked, relative):
+        result.error(location, f"path is case-mismatched with tracked Git path: {path_text}")
+        return
+
+    probe = skill_root
+    for part in lexical_parts:
+        probe = probe / part
+        if probe.is_symlink():
+            result.error(location, f"symlinks are not allowed in path components: {path_text}")
+            return
+
+    if not candidate.exists():
+        mode = _tracked_mode(repo_root, relative)
+        if mode is None:
+            result.error(location, f"file does not exist: {path_text}")
+        else:
+            result.error(
+                location,
+                f"file does not exist in working tree (tracked in Git index): {path_text}",
+            )
+        return
+
+    try:
+        resolved = candidate.resolve(strict=True)
+        resolved.relative_to(skill_root.resolve())
+    except ValueError:
+        result.error(location, f"path escapes skill root: {path_text}")
+        return
+    except OSError:
+        result.error(location, f"file does not exist: {path_text}")
+        return
+
+    if not resolved.is_file():
+        result.error(location, f"must resolve to a regular file: {path_text}")
+        return
+
+    if relative not in tracked:
+        result.error(location, f"file is not tracked by Git: {path_text}")
+        return
+
+    mode = _tracked_mode(repo_root, relative)
+    if mode is not None and mode == "120000":
+        result.error(location, f"tracked symlink is not allowed: {path_text}")
+
+
+def _semantic_checks(data: dict[str, Any], result: ValidationResult, repo_root: Path) -> None:
+    manifest_path = result.manifest_path
+    skill_root = manifest_path.parent.parent.resolve()
+    tracked = _tracked_files(repo_root)
+
+    _targeted_schema_version_errors(data, result)
+
+    skill_name = data.get("skill_name")
+    if skill_name != skill_root.name:
+        result.error(
+            "$.skill_name",
+            f"must equal containing skill directory name {skill_root.name!r}",
+        )
+
+    evals = data.get("evals")
+    if isinstance(evals, list):
+        result.case_count = len(evals)
+    else:
+        result.case_count = 0
+        return
+
+    seen_ids: dict[str, int] = {}
+    for index, case in enumerate(evals):
+        if not isinstance(case, dict):
+            continue
+        _validate_case_aliases(case, index, result)
+
+        case_id = case.get("id")
+        if isinstance(case_id, str):
+            if len(case_id) > 64:
+                result.error(f"$.evals[{index}].id", "must be 1-64 characters")
+            if not CASE_ID_RE.fullmatch(case_id):
+                result.error(
+                    f"$.evals[{index}].id",
+                    "must match ^[a-z0-9]+(?:-[a-z0-9]+)*$",
+                )
+            prior = seen_ids.get(case_id)
+            if prior is not None:
+                result.error(
+                    f"$.evals[{index}].id",
+                    f"duplicate case ID {case_id!r}; first seen at $.evals[{prior}].id",
+                )
+            else:
+                seen_ids[case_id] = index
+
+        assertions = case.get("assertions")
+        if isinstance(assertions, list):
+            seen_assertions: set[str] = set()
+            for assertion_index, assertion in enumerate(assertions):
+                if not _nonempty_string(assertion):
+                    result.error(
+                        f"$.evals[{index}].assertions[{assertion_index}]",
+                        "must be a nonempty non-whitespace string",
+                    )
+                    continue
+                if assertion in seen_assertions:
+                    result.error(
+                        f"$.evals[{index}].assertions[{assertion_index}]",
+                        "duplicate assertion values are not allowed",
+                    )
+                    continue
+                seen_assertions.add(assertion)
+
+        files = case.get("files")
+        if isinstance(files, list):
+            for file_index, file_value in enumerate(files):
+                _validate_fixture_path(
+                    file_value,
+                    skill_root=skill_root,
+                    repo_root=repo_root,
+                    tracked=tracked,
+                    location=f"$.evals[{index}].files[{file_index}]",
+                    result=result,
+                )
+
+
+def validate_manifest(manifest_path: Path, repo_root: Path) -> ValidationResult:
+    """Validate one manifest against schema and repository semantics."""
+    manifest_path = Path(manifest_path)
+    repo_root = Path(repo_root).resolve()
+    result = ValidationResult(manifest_path)
+    if not manifest_path.is_file():
+        return result
+
+    result.states["manifest_present"] = True
+    result.states["schema_valid"] = False
+    try:
+        data = _load_json_strict(manifest_path)
+    except DuplicateKeyError as exc:
+        result.error("$", f"duplicate JSON object key: {exc.key!r}")
+        return result
+    except json.JSONDecodeError as exc:
+        result.error("$", f"invalid JSON: {exc}")
+        return result
+    except OSError as exc:
+        result.error("$", f"unable to read manifest: {exc}")
+        return result
+    except TypeError as exc:
+        result.error("$", str(exc))
+        return result
+
+    _validate_schema(data, result)
+    _semantic_checks(data, result, repo_root)
+
+    result.states["schema_valid"] = not result.errors
+    return result
+
+
+def find_skill_manifests(repo_root: Path) -> list[Path]:
+    manifests = []
+    for skill_file in Path(repo_root).glob("**/SKILL.md"):
+        if "agent-council/profiles/skills" in skill_file.as_posix():
+            continue
+        manifest = skill_file.parent / "evals" / "evals.json"
+        if manifest.is_file():
+            manifests.append(manifest)
+    return sorted(manifests)
diff --git a/scripts/test-eval-coverage.py b/scripts/test-eval-coverage.py
index e3e555f..e761bb0 100644
--- a/scripts/test-eval-coverage.py
+++ b/scripts/test-eval-coverage.py
@@ -6,16 +6,20 @@ coverage-decrease detection, and threshold behavior.
 """
 
 import json
+import io
 import os
 import subprocess
 import sys
 import tempfile
 import unittest
+from contextlib import redirect_stderr, redirect_stdout
 from pathlib import Path
+from unittest import mock
 
 # Import the module under test.  The script is named eval-coverage.py
 # (hyphenated), so we load it via importlib rather than a normal import.
 import importlib.util  # noqa: E402
+from eval_validation import NOT_APPLICABLE  # noqa: E402
 
 SCRIPT_DIR = Path(__file__).resolve().parent
 _spec = importlib.util.spec_from_file_location(
@@ -49,7 +53,7 @@ def write_skill(repo: str, name: str, evals: list[dict] | None = None) -> None:
         evals_dir = skill_dir / "evals"
         evals_dir.mkdir(exist_ok=True)
         (evals_dir / "evals.json").write_text(
-            json.dumps({"skill_name": name, "evals": evals}, indent=2)
+            json.dumps({"schema_version": 1, "skill_name": name, "evals": evals}, indent=2)
         )
 
 
@@ -275,6 +279,24 @@ class TestCoverageDecreased(unittest.TestCase):
         self.assertAlmostEqual(base_pct, 100.0)
         self.assertAlmostEqual(head_pct, 50.0)
 
+    def test_replacing_valid_manifest_with_invalid_is_regression(self) -> None:
+        write_skill(self.repo, "s1", evals=[make_case("c1")])
+        base = self._commit("valid manifest")
+        (Path(self.repo) / "s1" / "evals" / "evals.json").write_text(
+            json.dumps({"schema_version": 1, "skill_name": "s1", "evals": []}),
+            encoding="utf-8",
+        )
+        self._commit("break manifest")
+        old_root = eval_coverage.ROOT
+        eval_coverage.ROOT = Path(self.repo)
+        try:
+            decreased, base_pct, head_pct = eval_coverage.coverage_decreased(base)
+        finally:
+            eval_coverage.ROOT = old_root
+        self.assertTrue(decreased)
+        self.assertAlmostEqual(base_pct, 100.0)
+        self.assertAlmostEqual(head_pct, 0.0)
+
     def test_no_decrease_when_stable(self) -> None:
         write_skill(self.repo, "s1", evals=[make_case("c1")])
         write_skill(self.repo, "s2")
@@ -361,5 +383,162 @@ class TestRatchetThresholds(unittest.TestCase):
         self.assertEqual([], errors)
 
 
+class TestBaseRefValidation(unittest.TestCase):
+    def setUp(self) -> None:
+        self.tmp = tempfile.TemporaryDirectory()
+        self.repo = self.tmp.name
+        git(self.repo, "init", "-b", "main")
+        git(self.repo, "config", "user.email", "test@test.invalid")
+        git(self.repo, "config", "user.name", "Test")
+        write_skill(self.repo, "alpha", evals=[make_case("c1")])
+        git(self.repo, "add", "-A")
+        git(self.repo, "commit", "-m", "initial")
+
+    def tearDown(self) -> None:
+        self.tmp.cleanup()
+
+    def test_main_rejects_invalid_modified_from_ref(self) -> None:
+        old_root = eval_coverage.ROOT
+        eval_coverage.ROOT = Path(self.repo)
+        stderr = io.StringIO()
+        try:
+            with mock.patch.object(
+                sys, "argv", ["eval-coverage.py", "--modified-from", "does-not-exist"]
+            ), redirect_stderr(stderr):
+                exit_code = eval_coverage.main()
+        finally:
+            eval_coverage.ROOT = old_root
+        self.assertEqual(2, exit_code)
+        self.assertEqual(
+            "ERROR: invalid --modified-from ref: 'does-not-exist' is not an existing commit\n",
+            stderr.getvalue(),
+        )
+
+    def test_main_rejects_option_like_modified_from_ref(self) -> None:
+        old_root = eval_coverage.ROOT
+        eval_coverage.ROOT = Path(self.repo)
+        stderr = io.StringIO()
+        try:
+            with mock.patch.object(
+                sys, "argv", ["eval-coverage.py", "--modified-from=--name-only"]
+            ), redirect_stderr(stderr):
+                exit_code = eval_coverage.main()
+        finally:
+            eval_coverage.ROOT = old_root
+        self.assertEqual(2, exit_code)
+        self.assertEqual(
+            "ERROR: invalid --modified-from ref: '--name-only' is not an existing commit\n",
+            stderr.getvalue(),
+        )
+
+    def test_main_accepts_valid_branch_ref(self) -> None:
+        old_root = eval_coverage.ROOT
+        eval_coverage.ROOT = Path(self.repo)
+        stderr = io.StringIO()
+        try:
+            with mock.patch.object(
+                sys, "argv", ["eval-coverage.py", "--modified-from", "main", "--json"]
+            ), redirect_stderr(stderr), redirect_stdout(io.StringIO()):
+                exit_code = eval_coverage.main()
+        finally:
+            eval_coverage.ROOT = old_root
+        self.assertEqual(0, exit_code)
+        self.assertEqual("", stderr.getvalue())
+
+
+class TestCoverageOutput(unittest.TestCase):
+    def setUp(self) -> None:
+        self.tmp = tempfile.TemporaryDirectory()
+        self.repo = self.tmp.name
+        git(self.repo, "init", "-b", "main")
+        write_skill(self.repo, "covered", evals=[make_case("c1")])
+        write_skill(self.repo, "uncovered")
+        git(self.repo, "add", "-A")
+
+    def tearDown(self) -> None:
+        self.tmp.cleanup()
+
+    def test_json_names_all_five_states_and_per_skill_values(self) -> None:
+        old_root = eval_coverage.ROOT
+        eval_coverage.ROOT = Path(self.repo)
+        output = io.StringIO()
+        try:
+            with mock.patch.object(sys, "argv", ["eval-coverage.py", "--json"]), redirect_stdout(output):
+                exit_code = eval_coverage.main()
+        finally:
+            eval_coverage.ROOT = old_root
+        self.assertEqual(0, exit_code)
+        report = json.loads(output.getvalue())
+        expected = {
+            "manifest_present",
+            "schema_valid",
+            "executable_grader_bindings_present",
+            "recent_run_evidence_present",
+            "release_gated_evidence_present",
+        }
+        self.assertEqual(expected, set(report["states"]))
+        self.assertEqual("supported", report["states"]["manifest_present"]["assessment"])
+        self.assertEqual("supported", report["states"]["schema_valid"]["assessment"])
+        for key in (
+            "executable_grader_bindings_present",
+            "recent_run_evidence_present",
+            "release_gated_evidence_present",
+        ):
+            self.assertEqual("not_assessed", report["states"][key]["assessment"])
+            self.assertIsNone(report["states"][key]["count"])
+            self.assertIsNone(report["states"][key]["percentage"])
+            self.assertTrue(report["states"][key]["reason"])
+        for skill in report["skills"]:
+            self.assertTrue(expected.issubset(skill))
+            self.assertIsInstance(skill["manifest_present"], bool)
+            self.assertIn(skill["schema_valid"], (True, False, NOT_APPLICABLE))
+            self.assertEqual("not_assessed", skill["executable_grader_bindings_present"])
+            self.assertEqual("not_assessed", skill["recent_run_evidence_present"])
+            self.assertEqual("not_assessed", skill["release_gated_evidence_present"])
+
+        per_skill = {entry["skill"]: entry for entry in report["skills"]}
+        self.assertTrue(per_skill["covered"]["schema_valid"])
+        self.assertEqual(NOT_APPLICABLE, per_skill["uncovered"]["schema_valid"])
+
+    def test_human_output_uses_same_state_names_and_not_assessed_wording(self) -> None:
+        old_root = eval_coverage.ROOT
+        eval_coverage.ROOT = Path(self.repo)
+        output = io.StringIO()
+        try:
+            with mock.patch.object(sys, "argv", ["eval-coverage.py"]), redirect_stdout(output):
+                exit_code = eval_coverage.main()
+        finally:
+            eval_coverage.ROOT = old_root
+        self.assertEqual(0, exit_code)
+        text = output.getvalue()
+        self.assertIn("manifest_present", text)
+        self.assertIn("schema_valid", text)
+        self.assertIn("executable_grader_bindings_present: not assessed", text)
+        self.assertIn("recent_run_evidence_present: not assessed", text)
+        self.assertIn("release_gated_evidence_present: not assessed", text)
+
+    def test_present_invalid_and_missing_manifest_reporting(self) -> None:
+        invalid_manifest = Path(self.repo) / "uncovered" / "evals"
+        invalid_manifest.mkdir(parents=True, exist_ok=True)
+        (invalid_manifest / "evals.json").write_text(
+            json.dumps({"schema_version": 1, "skill_name": "uncovered", "evals": []}),
+            encoding="utf-8",
+        )
+        old_root = eval_coverage.ROOT
+        eval_coverage.ROOT = Path(self.repo)
+        try:
+            covered = eval_coverage.check_eval_states(Path("covered"))
+            uncovered = eval_coverage.check_eval_states(Path("uncovered"))
+            missing = eval_coverage.check_eval_states(Path("missing"))
+        finally:
+            eval_coverage.ROOT = old_root
+        self.assertTrue(covered.states["manifest_present"])
+        self.assertTrue(covered.states["schema_valid"])
+        self.assertTrue(uncovered.states["manifest_present"])
+        self.assertFalse(uncovered.states["schema_valid"])
+        self.assertFalse(missing.states["manifest_present"])
+        self.assertEqual(NOT_APPLICABLE, missing.states["schema_valid"])
+
+
 if __name__ == "__main__":
     unittest.main()
diff --git a/scripts/test-eval-validation.py b/scripts/test-eval-validation.py
new file mode 100644
index 0000000..c77e9fe
--- /dev/null
+++ b/scripts/test-eval-validation.py
@@ -0,0 +1,388 @@
+#!/usr/bin/env python3
+"""Focused tests for the repository-owned eval manifest v1 contract."""
+
+from __future__ import annotations
+
+import json
+import os
+import subprocess
+import tempfile
+import unittest
+from pathlib import Path
+
+from eval_validation import NOT_APPLICABLE, SCHEMA_VERSION, find_skill_manifests, validate_manifest
+
+
+SCRIPT_DIR = Path(__file__).resolve().parent
+ROOT = SCRIPT_DIR.parent
+
+
+def git(repo: Path, *args: str) -> None:
+    subprocess.run(["git", *args], cwd=repo, check=True, capture_output=True)
+
+
+def git_output(repo: Path, *args: str) -> str:
+    completed = subprocess.run(
+        ["git", *args],
+        cwd=repo,
+        check=True,
+        capture_output=True,
+        text=True,
+    )
+    return completed.stdout
+
+
+def eval_case(**updates: object) -> dict[str, object]:
+    case: dict[str, object] = {
+        "id": "case-1",
+        "prompt": "Do the task.",
+        "expected_output": "A verified result.",
+        "assertions": ["Includes verification."],
+    }
+    case.update(updates)
+    return case
+
+
+class EvalValidationTest(unittest.TestCase):
+    def setUp(self) -> None:
+        self.tmp = tempfile.TemporaryDirectory()
+        self.root = Path(self.tmp.name)
+        git(self.root, "init", "-q")
+        git(self.root, "config", "user.email", "test@example.invalid")
+        git(self.root, "config", "user.name", "Test")
+        self.skill = self.root / "example"
+        (self.skill / "evals").mkdir(parents=True)
+        (self.skill / "SKILL.md").write_text("---\nname: example\ndescription: test\n---\n", encoding="utf-8")
+        self.manifest = self.skill / "evals" / "evals.json"
+
+    def tearDown(self) -> None:
+        self.tmp.cleanup()
+
+    def valid(self, **updates: object) -> dict[str, object]:
+        payload: dict[str, object] = {
+            "schema_version": SCHEMA_VERSION,
+            "skill_name": "example",
+            "evals": [eval_case()],
+        }
+        payload.update(updates)
+        return payload
+
+    def write(self, data: object, *, track_all: bool = True) -> None:
+        self.manifest.write_text(json.dumps(data, indent=2), encoding="utf-8")
+        if track_all:
+            git(self.root, "add", "-A")
+
+    def errors(self, data: object) -> list[str]:
+        self.write(data)
+        return validate_manifest(self.manifest, self.root).errors
+
+    def test_valid_manifest_passes(self) -> None:
+        self.write(self.valid())
+        result = validate_manifest(self.manifest, self.root)
+        self.assertTrue(result.states["manifest_present"])
+        self.assertTrue(result.states["schema_valid"])
+        self.assertEqual("not_assessed", result.states["executable_grader_bindings_present"])
+        self.assertEqual("not_assessed", result.states["recent_run_evidence_present"])
+        self.assertEqual("not_assessed", result.states["release_gated_evidence_present"])
+        self.assertEqual([], result.errors)
+
+    def test_missing_manifest_reports_schema_valid_not_applicable(self) -> None:
+        missing_manifest = self.skill / "evals" / "missing.json"
+        result = validate_manifest(missing_manifest, self.root)
+        self.assertFalse(result.states["manifest_present"])
+        self.assertEqual(NOT_APPLICABLE, result.states["schema_valid"])
+        self.assertEqual([], result.errors)
+
+    def test_targeted_schema_version_errors(self) -> None:
+        missing_errors = self.errors({"skill_name": "example", "evals": [eval_case()]})
+        self.assertTrue(any("missing required schema_version" in error for error in missing_errors))
+
+        string_errors = self.errors(self.valid(schema_version="1"))
+        self.assertTrue(any("must be integer 1, not a string" in error for error in string_errors))
+
+        unknown_errors = self.errors(self.valid(schema_version=2))
+        self.assertTrue(any("unsupported schema_version" in error for error in unknown_errors))
+
+    def test_boolean_and_non_integer_schema_version_errors(self) -> None:
+        bool_errors = self.errors(self.valid(schema_version=True))
+        self.assertTrue(any("schema_version must be integer 1" in error for error in bool_errors))
+
+        float_errors = self.errors(self.valid(schema_version=1.5))
+        self.assertTrue(any("schema_version must be integer 1" in error for error in float_errors))
+
+    def test_expectations_alias_errors(self) -> None:
+        legacy_only = eval_case()
+        legacy_only.pop("assertions")
+        legacy_only["expectations"] = ["legacy"]
+        errors = self.errors(self.valid(evals=[legacy_only]))
+        self.assertTrue(any("expectations is not supported" in error for error in errors))
+
+        both = eval_case(expectations=["legacy"])
+        errors = self.errors(self.valid(evals=[both]))
+        self.assertTrue(any("cannot both be present" in error for error in errors))
+
+    def test_missing_required_fields_fail(self) -> None:
+        for field in ("id", "prompt", "expected_output", "assertions"):
+            with self.subTest(field=field):
+                case = eval_case()
+                case.pop(field)
+                errors = self.errors(self.valid(evals=[case]))
+                self.assertTrue(any(field in error for error in errors))
+
+    def test_whitespace_prompt_and_expected_output_fail(self) -> None:
+        errors = self.errors(self.valid(evals=[eval_case(prompt="   ")]))
+        self.assertTrue(any("prompt" in error for error in errors))
+        errors = self.errors(self.valid(evals=[eval_case(expected_output="\t")]))
+        self.assertTrue(any("expected_output" in error for error in errors))
+
+    def test_invalid_ids_fail(self) -> None:
+        invalid_values: list[object] = [123, "", "UPPER", "has spaces", "path/slash", "a" * 65]
+        for bad in invalid_values:
+            with self.subTest(bad=bad):
+                errors = self.errors(self.valid(evals=[eval_case(id=bad)]))
+                self.assertTrue(any("id" in error for error in errors))
+
+    def test_duplicate_ids_fail(self) -> None:
+        errors = self.errors(self.valid(evals=[eval_case(id="dup"), eval_case(id="dup")]))
+        self.assertTrue(any("duplicate case ID" in error for error in errors))
+
+    def test_duplicate_assertions_fail(self) -> None:
+        errors = self.errors(self.valid(evals=[eval_case(assertions=["A", "A"])]))
+        self.assertTrue(any("duplicate assertion" in error for error in errors))
+
+    def test_empty_evals_fail(self) -> None:
+        errors = self.errors(self.valid(evals=[]))
+        self.assertTrue(any("evals" in error and "non-empty" in error.lower() for error in errors))
+
+    def test_empty_and_whitespace_only_assertions_fail(self) -> None:
+        for assertion in ("", "   "):
+            with self.subTest(assertion=repr(assertion)):
+                errors = self.errors(self.valid(evals=[eval_case(assertions=[assertion])]))
+                self.assertTrue(any("nonempty non-whitespace" in error for error in errors))
+
+    def test_unknown_top_level_and_case_fields_fail(self) -> None:
+        top_level_errors = self.errors(self.valid(unknown_field=True))
+        self.assertTrue(
+            any("Additional properties" in error and "unknown_field" in error for error in top_level_errors)
+        )
+
+        case_errors = self.errors(self.valid(evals=[eval_case(unknown_field=True)]))
+        self.assertTrue(
+            any("Additional properties" in error and "unknown_field" in error for error in case_errors)
+        )
+
+    def test_evidence_property_is_rejected_as_unknown_v1_property(self) -> None:
+        errors = self.errors(self.valid(evidence={"grader_bindings": ["scripts/grader.py"]}))
+        self.assertTrue(any("Additional properties" in error and "evidence" in error for error in errors))
+
+    def test_duplicate_json_object_keys_fail_before_semantic_validation(self) -> None:
+        self.manifest.write_text(
+            """
+{
+  "schema_version": 1,
+  "schema_version": 2,
+  "skill_name": "example",
+  "evals": [{
+    "id": "case-1",
+    "prompt": "P",
+    "expected_output": "E",
+    "assertions": ["A"]
+  }]
+}
+""".strip()
+            + "\n",
+            encoding="utf-8",
+        )
+        git(self.root, "add", "-A")
+        result = validate_manifest(self.manifest, self.root)
+        self.assertFalse(result.states["schema_valid"])
+        self.assertEqual(1, len(result.errors))
+        self.assertIn("duplicate JSON object key", result.errors[0])
+
+    def test_malformed_json_manifest_is_present_but_schema_invalid(self) -> None:
+        self.manifest.write_text("{\n", encoding="utf-8")
+        git(self.root, "add", "-A")
+        result = validate_manifest(self.manifest, self.root)
+        self.assertTrue(result.states["manifest_present"])
+        self.assertFalse(result.states["schema_valid"])
+        self.assertTrue(any("invalid JSON" in error for error in result.errors))
+
+    def test_skill_name_must_match_containing_directory(self) -> None:
+        errors = self.errors(self.valid(skill_name="wrong"))
+        self.assertTrue(any("containing skill directory" in error for error in errors))
+
+    def test_files_accepts_tracked_regular_file(self) -> None:
+        fixture = self.skill / "fixtures" / "input.json"
+        fixture.parent.mkdir(parents=True, exist_ok=True)
+        fixture.write_text("{}\n", encoding="utf-8")
+        self.write(self.valid(evals=[eval_case(files=["fixtures/input.json"])]))
+        result = validate_manifest(self.manifest, self.root)
+        self.assertTrue(result.states["schema_valid"])
+
+    def test_data_dot_dot_filename_is_allowed(self) -> None:
+        fixture = self.skill / "fixtures" / "data..json"
+        fixture.parent.mkdir(parents=True, exist_ok=True)
+        fixture.write_text("{}\n", encoding="utf-8")
+        self.write(self.valid(evals=[eval_case(files=["fixtures/data..json"])]))
+        result = validate_manifest(self.manifest, self.root)
+        self.assertTrue(result.states["schema_valid"])
+
+    def test_duplicate_file_paths_fail(self) -> None:
+        fixture = self.skill / "fixtures" / "input.json"
+        fixture.parent.mkdir(parents=True, exist_ok=True)
+        fixture.write_text("{}\n", encoding="utf-8")
+        errors = self.errors(
+            self.valid(evals=[eval_case(files=["fixtures/input.json", "fixtures/input.json"])]),
+        )
+        self.assertTrue(any("non-unique elements" in error for error in errors))
+
+    def test_lexical_dot_empty_and_trailing_slash_paths_fail(self) -> None:
+        fixture = self.skill / "fixtures" / "input.json"
+        fixture.parent.mkdir(parents=True, exist_ok=True)
+        fixture.write_text("{}\n", encoding="utf-8")
+
+        for bad in (
+            "fixtures/./input.json",
+            "fixtures//input.json",
+            "./input.json",
+            "fixtures/input.json/",
+        ):
+            with self.subTest(path=bad):
+                errors = self.errors(self.valid(evals=[eval_case(files=[bad])]))
+                self.assertTrue(any("files[0]" in error for error in errors))
+
+    def test_symlink_component_escaping_skill_is_rejected(self) -> None:
+        external_dir = self.root / "external"
+        external_dir.mkdir(parents=True, exist_ok=True)
+        (external_dir / "outside.json").write_text("{}\n", encoding="utf-8")
+
+        fixtures_dir = self.skill / "fixtures"
+        fixtures_dir.mkdir(parents=True, exist_ok=True)
+        os.symlink(external_dir, fixtures_dir / "external")
+        git(self.root, "add", "-A")
+
+        errors = self.errors(self.valid(evals=[eval_case(files=["fixtures/external/outside.json"])]))
+        self.assertTrue(any("symlink" in error for error in errors))
+
+    def test_tracked_but_missing_file_fails_when_index_still_lists_it(self) -> None:
+        fixture = self.skill / "fixtures" / "input.json"
+        fixture.parent.mkdir(parents=True, exist_ok=True)
+        fixture.write_text("{}\n", encoding="utf-8")
+        self.write(self.valid(evals=[eval_case(files=["fixtures/input.json"])]))
+
+        fixture.unlink()
+        tracked_entry = git_output(
+            self.root,
+            "ls-files",
+            "-s",
+            "--",
+            str(fixture.relative_to(self.root)),
+        )
+        self.assertNotEqual("", tracked_entry)
+
+        errors = validate_manifest(self.manifest, self.root).errors
+        self.assertTrue(any("does not exist in working tree" in error for error in errors))
+
+    def test_nested_bundle_skill_name_matches_leaf_directory(self) -> None:
+        nested_skill = self.root / "bundles" / "demo-bundle" / "skills" / "child-skill"
+        (nested_skill / "evals").mkdir(parents=True)
+        (nested_skill / "SKILL.md").write_text(
+            "---\nname: child-skill\ndescription: test\n---\n",
+            encoding="utf-8",
+        )
+        nested_manifest = nested_skill / "evals" / "evals.json"
+        nested_manifest.write_text(
+            json.dumps(
+                {
+                    "schema_version": SCHEMA_VERSION,
+                    "skill_name": "child-skill",
+                    "evals": [eval_case()],
+                },
+                indent=2,
+            ),
+            encoding="utf-8",
+        )
+        git(self.root, "add", "-A")
+
+        result = validate_manifest(nested_manifest, self.root)
+        self.assertTrue(result.states["schema_valid"])
+
+    def test_file_boundary_failures(self) -> None:
+        tracked = self.skill / "Fixtures" / "Input.json"
+        tracked.parent.mkdir(parents=True, exist_ok=True)
+        tracked.write_text("{}\n", encoding="utf-8")
+        outside = self.root / "outside.json"
+        outside.write_text("{}\n", encoding="utf-8")
+        directory = self.skill / "fixtures"
+        directory.mkdir(parents=True, exist_ok=True)
+        symlink_target = directory / "target.json"
+        symlink_target.write_text("{}\n", encoding="utf-8")
+        os.symlink(symlink_target, directory / "linked.json")
+        git(self.root, "add", "-A")
+
+        invalid_paths = [
+            str(tracked.resolve()),
+            "../outside.json",
+            "fixtures/missing.json",
+            "fixtures",
+            "fixtures\\bad.json",
+            "fixtures/linked.json",
+            "fixtures/\u0001bad.json",
+            "fixtures/./input.json",
+            "Fixtures/input.json",
+        ]
+        for bad in invalid_paths:
+            with self.subTest(path=bad):
+                errors = self.errors(self.valid(evals=[eval_case(files=[bad])]))
+                self.assertTrue(any("files[0]" in error for error in errors))
+
+    def test_missing_and_untracked_fixture_paths_report_distinct_reasons(self) -> None:
+        untracked = self.skill / "fixtures" / "untracked.json"
+        untracked.parent.mkdir(parents=True, exist_ok=True)
+        untracked.write_text("{}\n", encoding="utf-8")
+
+        self.write(self.valid(evals=[eval_case(files=["fixtures/missing.json"])]), track_all=False)
+        git(self.root, "add", str(self.manifest.relative_to(self.root)))
+        missing_errors = validate_manifest(self.manifest, self.root).errors
+        self.assertTrue(any("does not exist" in error for error in missing_errors))
+        self.assertFalse(any("not tracked by Git" in error for error in missing_errors))
+
+        self.write(self.valid(evals=[eval_case(files=["fixtures/untracked.json"])]), track_all=False)
+        git(self.root, "add", str(self.manifest.relative_to(self.root)))
+        tracked_untracked = git_output(
+            self.root,
+            "ls-files",
+            "--",
+            str(untracked.relative_to(self.root)),
+        )
+        self.assertEqual("", tracked_untracked)
+        untracked_errors = validate_manifest(self.manifest, self.root).errors
+        self.assertTrue(any("not tracked by Git" in error for error in untracked_errors))
+        self.assertFalse(any("does not exist" in error for error in untracked_errors))
+
+
+class RepositoryManifestTest(unittest.TestCase):
+    def test_known_migrated_set_is_present_and_all_discovered_manifests_validate(self) -> None:
+        known = {
+            "de-spin/evals/evals.json",
+            "esp32-development/evals/evals.json",
+            "raleigh/evals/evals.json",
+            "restic/evals/evals.json",
+            "supabase/evals/evals.json",
+            "vercel-eve/evals/evals.json",
+            "verification-methodology/evals/evals.json",
+        }
+        manifests = find_skill_manifests(ROOT)
+        discovered = {str(path.relative_to(ROOT)) for path in manifests}
+        self.assertTrue(known.issubset(discovered))
+
+        invalid = []
+        for manifest in manifests:
+            result = validate_manifest(manifest, ROOT)
+            if result.states["schema_valid"] is not True:
+                invalid.append((manifest, result.errors))
+        self.assertEqual([], invalid)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/scripts/validate-evals.py b/scripts/validate-evals.py
new file mode 100644
index 0000000..f21053d
--- /dev/null
+++ b/scripts/validate-evals.py
@@ -0,0 +1,27 @@
+#!/usr/bin/env python3
+"""Validate every eval manifest against the repository-owned v1 contract."""
+
+import sys
+from pathlib import Path
+
+from eval_validation import find_skill_manifests, validate_manifest
+
+ROOT = Path(__file__).resolve().parent.parent
+
+
+def main() -> int:
+    manifests = find_skill_manifests(ROOT)
+    errors = []
+    for manifest in manifests:
+        errors.extend(validate_manifest(manifest, ROOT).errors)
+    if errors:
+        print("\n".join(errors), file=sys.stderr)
+        return 1
+    print(
+        f"Validated {len(manifests)} eval manifests against repository schema v1 and semantic repository checks."
+    )
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/scripts/validate-skills.rb b/scripts/validate-skills.rb
index aab38f9..2a2c3e7 100755
--- a/scripts/validate-skills.rb
+++ b/scripts/validate-skills.rb
@@ -4,6 +4,7 @@
 require "yaml"
 require "set"
 require "json"
+require "open3"
 
 ROOT = File.expand_path("..", __dir__)
 ALLOWED_FIELDS = %w[name description license compatibility metadata allowed-tools].freeze
@@ -12,6 +13,8 @@ GRANDFATHER_FILE = File.join(ROOT, "scripts", "grandfathered-skills.txt")
 MIN_EVAL_CASES = 5
 
 errors = []
+eval_stdout, eval_stderr, eval_status = Open3.capture3("python3", File.join(ROOT, "scripts", "validate-evals.py"), chdir: ROOT)
+errors.concat(eval_stderr.lines(chomp: true)) unless eval_status.success?
 skills = Dir.glob("#{ROOT}/**/SKILL.md").sort.reject do |skill|
   skill.include?("/agent-council/profiles/skills/")
 end
diff --git a/supabase/evals/evals.json b/supabase/evals/evals.json
index 031a0ca..a77f979 100644
--- a/supabase/evals/evals.json
+++ b/supabase/evals/evals.json
@@ -1,4 +1,5 @@
 {
+  "schema_version": 1,
   "skill_name": "supabase",
   "evals": [
     {
diff --git a/vercel-eve/evals/evals.json b/vercel-eve/evals/evals.json
index d878c3f..fa8b4f6 100644
--- a/vercel-eve/evals/evals.json
+++ b/vercel-eve/evals/evals.json
@@ -1,4 +1,5 @@
 {
+  "schema_version": 1,
   "skill_name": "vercel-eve",
   "evals": [
     {
diff --git a/verification-methodology/evals/evals.json b/verification-methodology/evals/evals.json
index 40775c5..a486225 100644
--- a/verification-methodology/evals/evals.json
+++ b/verification-methodology/evals/evals.json
@@ -1,4 +1,5 @@
 {
+  "schema_version": 1,
   "skill_name": "verification-methodology",
   "evals": [
     {