fix(agent): preserve raw Claude session lines

[daryllimyt]

Summary

• Store raw Claude session JSONL bytes for exact resume reconstruction.
• Escape NUL codepoints in the JSONB projection so Postgres accepts affected session lines.
• Prefer raw session lines during resume while preserving the existing JSONB fallback path.

Tests

• uv run pytest tests/unit/test_agent_session_messages.py
• uv run ruff check tests/unit/test_agent_session_messages.py tracecat/agent/executor/loopback.py tracecat/agent/session/service.py tracecat/db/models.py alembic/versions/0e4c0a2b7f91_add_raw_agent_session_line.py
• uv run ruff format --check tests/unit/test_agent_session_messages.py tracecat/agent/executor/loopback.py tracecat/agent/session/service.py tracecat/db/models.py alembic/versions/0e4c0a2b7f91_add_raw_agent_session_line.py
• uv run basedpyright tests/unit/test_agent_session_messages.py tracecat/agent/executor/loopback.py tracecat/agent/session/service.py tracecat/db/models.py alembic/versions/0e4c0a2b7f91_add_raw_agent_session_line.py

[cubic-dev-ai]

No issues found across 5 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Re-trigger cubic}

[zeropath-ai]

✅ No security or compliance issues detected. Reviewed everything up to 2bfadef.

Security Overview

• 🔎 Scanned files: 2 changed file(s)
• 🔗 Scan Link: https://zeropath.com/app/repositories/00dffd6c-8834-4dc9-b6d8-b44cd1622986?scanId=4b4aa5c1-ef18-4475-86eb-07575f0f66c7&codeScanTypes=PrScan&tab=issues

Detected Code Changes

Change Type

Relevant files

Enhancement

► tests/unit/test_agent_session_messages.py     Add test for _session_line_db_content and _session_line_jsonb_safe_content     Add test for persist_session_line logic including NUL sanitization and sdk_session_id update ► tracecat/agent/executor/loopback.py     Implement _jsonb_safe_value and _session_line_jsonb_safe_content for NUL sanitization     Implement _is_jsonb_nul_error to detect PostgreSQL NUL errors     Add retry logic in _persist_session_line for NUL errors     Update _persist_session_line to handle setting sdk_session_id on the first line

[daryllimyt]

there is a migration in this but should be non-disruptive

[jordan-umusu]

LGTM but why go beyond escaping the invalid null checkpoint here?

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Preserve NUL session bytes for resume

When a Claude JSONL line contains \u0000, _session_line_from_json decodes it to an actual NUL, and this fallback changes it to the six-character string \\u0000 before storing it. AgentSessionService.load_session_history later reconstructs the resume JSONL from entry.content with orjson.dumps(content), so affected sessions resume with a literal backslash-u sequence instead of the original NUL value. For tool outputs or message text containing NULs, persistence now succeeds but the stored session is no longer an exact Claude session line, which undermines the raw-resume fix this change is meant to provide.

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