Return a read operation's output from operations propose

CHANGELOG.md

@@ -8,6 +8,12 @@ Notable changes to Cloudfall. The format follows
 
 ### Added
 
+- `operations propose` returns a read operation's play output in
+  `data.output`, so an agent acts on what the operation reported without
+  opening the decision's `.diff` file; the record keeps the file as before.
+  The output is the hosts' text, so `data` carries `_trusted: false`.
+  A proposed change answers `output: null`, and the read operation's MCP
+  tool no longer suggests approving a run that needs no approval (#24)
 - `cloudfall why` answers "why did the agent do that" from the decision
   records alone, for a host (`--host`), an operation (`--operation`) or a
   time window (`--since`, `--until`, ISO 8601 or a bare date), as JSON or

sdk/src/cloudfall/app.py

@@ -105,6 +105,7 @@
     DecisionStatus,
     DecisionStore,
     ProposalRequest,
+    Requirement,
     Targets,
     approve,
     propose,
@@ -1947,12 +1948,17 @@ class ApproveDecisionArgs(DecisionsArgs):
 
 @dataclass(frozen=True, slots=True)
 class Decided:
-    """One decision record, and what to do next when it waits for approval."""
+    """One decision record, and what to do next when it waits for approval.
+
+    A read operation has run by the time it is recorded, so its play output
+    comes back with the record; it is the hosts' text, never trusted.
+    """
 
     effect: str
     status: str
     decision: dict[str, object] = Out(ordered=True)
     next: list[str] = Out(ordered=True)
+    output: str | None = Out(default=None, external=True)
 
 
 def _decision_failed(error: DecisionError) -> Exception:
@@ -2003,8 +2009,17 @@ def operations_propose(args: ProposeArgs, ctx: Ctx) -> Decided:
         decision = propose(request, store, run=_check_runner(ctx, args.root))
     except DecisionError as error:
         raise _decision_failed(error) from error
+    output = (
+        (args.root / decision.check.diff.path).read_text(encoding="utf-8")
+        if decision.requirement is Requirement.RUNS_FREELY
+        else None
+    )
     decided = Decided(
-        effect="created", status="ok", decision=decision.as_document(), next=[]
+        effect="created",
+        status="ok",
+        decision=decision.as_document(),
+        next=[],
+        output=output,
     )
     if decision.check.exit_code != 0:
         message = (
@@ -3462,6 +3477,8 @@ def propose_operation(arguments: Mapping[str, object], ctx: Ctx) -> Decided:
             ),
             ctx,
         )
+        if operation.risk is RiskLevel.READ:
+            return decided
         record = cast("Mapping[str, Mapping[str, object]]", decided.decision)
         approve = f"{APPROVAL_COMMAND} {record['metadata']['id']} --yes"
         return dataclasses.replace(decided, next=[approve])

sdk/tests/test_decision.py

@@ -394,6 +394,58 @@ def test_the_cli_proposes_and_then_lists_the_record(
     assert payload["data"]["decisions"][0]["spec"]["operation"]["id"] == "deploy"
 
 
+def test_the_cli_returns_what_a_read_operation_reported(
+    tmp_path: Path, capsys: pytest.CaptureFixture[str]
+) -> None:
+    repository = _repository(tmp_path)
+    (repository / "playbooks" / "facts.yml").write_text(
+        "---\n- hosts: localhost\n  connection: local\n  gather_facts: false\n"
+        "  tasks:\n    - name: Report\n      ansible.builtin.debug:\n"
+        "        msg: /var/log/shop holds 36G\n",
+        encoding="utf-8",
+    )
+
+    exit_code = main(
+        ["operations", "propose", "facts", "--repository", str(repository)]
+    )
+
+    payload = json.loads(capsys.readouterr().out)
+    assert exit_code == 0
+    assert "/var/log/shop holds 36G" in payload["data"]["output"]
+    assert payload["data"]["_trusted"] is False
+    assert payload["data"]["next"] == []
+
+
+def test_the_cli_returns_no_output_for_a_proposed_change(
+    tmp_path: Path, capsys: pytest.CaptureFixture[str]
+) -> None:
+    repository = _repository(tmp_path)
+    _observations(repository, "web-1")
+    (repository / "playbooks" / "deploy.yml").write_text(
+        "---\n- hosts: localhost\n  connection: local\n  gather_facts: false\n"
+        "  tasks:\n    - name: Nothing\n      ansible.builtin.debug:\n"
+        "        msg: nothing\n",
+        encoding="utf-8",
+    )
+
+    main(
+        [
+            "operations",
+            "propose",
+            "deploy",
+            "--repository",
+            str(repository),
+            "--target",
+            "localhost",
+            "--input",
+            "version=1.4.0",
+        ]
+    )
+
+    payload = json.loads(capsys.readouterr().out)
+    assert payload["data"]["output"] is None
+
+
 def test_the_cli_reports_a_gate_refusal_as_json(
     tmp_path: Path, capsys: pytest.CaptureFixture[str]
 ) -> None: