Session timeline

1. Inspect the capabilities of canvas vscode-session-timeline.
2. Open it with instance ID session-timeline and no input. Reuse that instance when asked to show it again.
3. Use setFilter to change the search text or visible categories when requested. Categories are system, user, assistant, tool, and subagent. An empty category list intentionally shows no events.
4. Use refresh to reload SDK history, or getStatus to inspect counts and loading errors.

The canvas reads the joined session through the Copilot SDK, not a VS Code session directory. It updates automatically; do not repeatedly call refresh. Expanding an event shows its readable details and original SDK records. The user can download the SDK events as JSONL with Export events.

The Current tools panel shows the live main-agent tool catalog, with total/deferred counts and expandable metadata. It refreshes on tool changes and manual refresh; unsupported hosts show an explicit error. It is not a historical per-turn or subagent inventory, and deferred tools are not necessarily loaded for the model. Find searches both this catalog and request Tools cards, opening matching sections automatically. Event category filters apply to the cards, not the current catalog. Text view and event export do not include the current catalog.

Request Tools cards are persisted through the SDK's session-workspace file API in session-timeline-request-tools.json and restored after extension restarts. Historical requests without a saved snapshot are not backfilled. Removed requests lose their saved snapshots. Storage errors appear in the timeline and getStatus as persistenceError; unsupported hosts keep event history usable but cannot persist snapshots. These local snapshots are not included in SDK-event export.

System-prompt tool guidance describes prompt text, not an authoritative inventory of tools offered to the model. Reasoning and other optional fields are available only when the runtime emits them. History does not recover past ephemeral streaming events.

If the canvas is unavailable, report that this plugin requires a Copilot host with canvas extensions enabled. Do not substitute a guessed filesystem path or install another copy of the extension.