Codex Session Observatory v2.0.0

v2.0.0 is a Major Update. Session Navigator, a three-panel workspace, and a redesigned reading and reuse workflow make this a substantial change to how you work with local Codex sessions.

Session Navigator

• Browse local sessions directly from the new Sessions panel, with Flat and Hierarchical views.
• Load additional Flat results as you scroll, or explore the session date folders.
• Open ordinary and ChatGPT Handoff sessions, including .jsonl.zst compressed records.
• Reload the session list independently of the current Transcript and Collection.
• Use a session's context menu to Open, Open Containing Folder, or Export Worklog, including export without selecting that session.
• Show missing local title metadata as Untitled Session, with identifying information in a tooltip. Recent conversation activity emphasizes titles without reordering the list.

Three-panel workspace and desktop workflow

• Arrange Sessions / Transcript / Collection in one workspace with independent side-panel toggles and resizable boundaries.
• Use the available height consistently, with independent scrolling and Top/Bottom controls for each panel.
• Simplify the header around session information, Resume copying, appearance, filters, and common action feedback.
• Move Capture and Transcript Refresh into the Transcript header and streamline Collection controls.
• Separate the Loaded/Idle badge from Reset and consolidate action results, progress, warnings, and errors into the Status line.
• Update the default window to 1360×760, with a 1100×720 minimum.

Appearance and readability

• Add independent Text and Code selectors using fonts installed on Windows, with saved choices and a Default option.
• Use the allocated Transcript width consistently across Terminal, Markdown, DM, and DM Dark.
• Improve DM inline-code and role/timestamp contrast, shared typography, panel boundaries, and icon controls.

Session handling and responsiveness

• Stream plain and zstd-compressed JSONL through the existing parsing flow.
• Fix Refresh control reactivity while preserving Collection snapshots, source order, and panel state.
• Move blocking parse and Export file work away from the native window thread, with controlled file-operation concurrency.
• Preserve existing message DOM across filter changes using stable identities, including distinct duplicate messages.
• Reduce large-transcript DOM overhead by removing redundant ordinary-text wrappers while retaining full content and semantic rendering.

In recorded single-PC synthetic tests, sampled filter DOM reuse improved from 1/20 to 20/20 messages. A large Export's maximum native message-response probe delay fell from 326.8 to 3.4 ms; this measures responsiveness rather than Export throughput. In a separate Terminal test with 2,500 visible messages, HTML elements fell from 107,942 to 77,942, and the median initial-display time across three runs changed from 3,092.9 to 2,831.3 ms.

These are distinct measurements with different baselines, not combined or universal performance guarantees. Large-body redisplay costs remain, and overall application memory savings were not established for the final rendering change. Conditions, validation, and rejected approaches are documented in Performance History.

Compatibility and outputs

• Keep original JSONL records unchanged and preserve transcript order.
• Keep Collection separate from Capture Transcript and complete-session Worklog export.
• Retain existing Worklog format and overwrite safeguards.

This remains a portable Windows x64 release with no installer or automatic update behavior.