[Rahul (rahul05ranjan)]

Fixes #182.

Five readers of agent CLI output parsed each line with json.loads and then called .get on the result, so one line that parses but is not an object (null, 42, "text", [1, 2]) raised AttributeError and lost the whole probe / side call / tool check:

• probe.run_session — Copilot -p --output-format json stdout
• probe.inspect_session — Copilot's events.jsonl (also had no except ValueError, so a corrupt line carrying the "hook.end" prefilter crashed before .get)
• sidecall.codex_call — codex exec --json stdout
• sidecall.copilot_call — Copilot -p stdout
• toolcheck._init_tools — claude -p --output-format stream-json stdout

#150 added the isinstance(ev, dict) check to the trace readers; these plugin-side readers of external process output are the same class and were not in that sweep.

Verification

• New regression tests fail on main@264e7a7 (AttributeError in all three, plus the ValueError path in inspect_session) and pass with the fix:
  • test_the_side_calls_skip_json_lines_that_are_not_objects — junk lines (null, [1,2], "text", 42) ahead of the real item.completed / assistant.message + result events; codex and copilot side calls and probe.run_session still read the reply, session id and answer.
  • test_inspect_session_skips_hook_lines_that_do_not_parse — an unparseable {broken ... hook.end line and a parses-but-not-an-object "hook.end sessionStart" string; the inspection completes and reports injected: False.
  • test_the_init_probe_skips_json_lines_that_are_not_objects (tests/test_toolcheck_measure.py) — the real Popen probe prints four junk lines before the system/init event; tools and version still returned.
• Full offline suite (python3 -m pytest tests/ -q) green with the fix; standard library only.

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[Muhammad Abdullah Butt (1AbdullahButt)]

I compared each changed loop with main. Four of the five changes are the straightforward isinstance guard, but the inspect_session rewrite changes what it reads.

tokeneconomizer/plugin/probe.py:155 drops the .get("output") step. On main it is:

out = (json.loads(line).get("data") or {}).get("output") or {}

and the PR has:

out = (ev.get("data") or {}) if isinstance(ev, dict) else {}

The next line still looks up out.get("additionalContext"), so it now reads data.additionalContext rather than data.output.additionalContext. A real Copilot hook.end / sessionStart line would then always report injected: False. The new test can't catch this, because its only well-formed hook line is a bare string and it asserts injected is False. Suggested:

data = ev.get("data") if isinstance(ev, dict) else None
out = (data.get("output") if isinstance(data, dict) else None) or {}
injected = injected or "fails here" in ((out.get("additionalContext") if isinstance(out, dict) else "") or "")

A test with a valid {"type": "hook.end", "data": {"hookType": "sessionStart", "output": {"additionalContext": "... fails here ..."}}} line asserting injected is True would pin it.

The same crash is still one level down. The guard covers the top-level event, but the nested values are still trusted:

• sidecall.py:317: item = ev.get("item") or {}, then item.get("type") raises on {"type": "item.completed", "item": "x"}.
• sidecall.py:731 and probe.py:136: (ev.get("data") or {}).get("content") raises on "data": [..].

These are less likely than a stray null line. If the aim of #182 is that one bad line never loses the call, an isinstance(..., dict) check on item and data (or a small _obj(v) helper that returns v if isinstance(v, dict) else {}) would cover them too.

Reviewed with help from Claude Code.