fix: Chronicle agent_name backfill, summary JSON filtering, schema description

[digitarald]

Fixes the remaining open sub-issues of #312292 (Chronicle local schema drift).

Changes

extractAgentName — fixes #312296

sessions.agent_name was always 'unknown' in the local store because:

1. _initSession fell through to 'unknown' when the span lacked gen_ai.agent.name
2. _bufferSessionUpsert didn't include agent_name in its merge list, so later spans couldn't correct it

Fix: Add extractAgentName(span) with a fallback chain: attribute → span-name parsing ("invoke_agent copilot" → "copilot") → 'unknown'. Use it in _initSession, add agent_name to the _bufferSessionUpsert merge list (prerequisite for backfill to work), and backfill from _backfillFromSpanAttributes.

extractPlainTextFromContent — fixes #312295

sessions.summary was stored verbatim from USER_REQUEST span attributes or first user message events, which can be structured JSON (e.g. [{"type":"tool_result","content":"..."}]). This broke LIKE-based queries and the FTS index.

Fix: Add extractPlainTextFromContent(content) that detects JSON content and extracts human-readable text from known structures (multi-modal text parts, chat message objects), returning undefined for unrecognized JSON (tool results, images, etc.) to skip the summary write entirely. Route all three summary write sites through it:

• _backfillFromSpanAttributes (sessionStoreTracker.ts)
• _handleAgentSpan (sessionStoreTracker.ts, both event and fallback paths)
• processAssistantResponse summary path in sessionReindexer.ts (was missing from prior fix attempts)

Schema description — addresses #312292

Updated the local schema description in _getSchemaDescription():

• agent_name: added example values ('GitHub Copilot Chat', 'copilotcli', 'claude')
• host_type: noted it's always 'vscode' locally (not a distinguishing field)
• summary: removed the raw JSON warning now that the write path filters it
• search_index: clarified it indexes turns.user_message and turns.assistant_response content

Testing

16 new unit tests in sessionStoreTracking.spec.ts:

• extractAgentName: attribute present, span-name fallback, multi-word names, empty suffix, empty attribute, non-invoke span
• extractPlainTextFromContent: plain text, empty string, text parts, tool results, chat messages, array content, truncated JSON

[github-actions]

Screenshot Changes

Base: 32db9092 Current: a67b0e8c

Changed (2)

agentSessionsViewer/WithBadge/Dark

Before	After

agentSessionsViewer/WithBadge/Light

Before	After

[Copilot]

Pull request overview

This PR addresses remaining local Chronicle schema/data drift issues by improving how session agent_name and summary are populated from OTel spans, and by updating the Chronicle local schema prompt to better match actual stored data.

Changes:

• Add extractAgentName(span) and wire it into session initialization, buffered upserts, and span-attribute backfill to enable sessions.agent_name correction/backfill.
• Add extractPlainTextFromContent(content) and route all local sessions.summary write paths through it to avoid storing structured JSON blobs as summaries.
• Update Chronicle local schema description text to reflect updated agent_name, summary, and search_index semantics.

Show a summary per file

File	Description
extensions/copilot/src/extension/intents/node/chronicleIntent.ts	Updates the local schema description text shown to the Chronicle intent LLM.
extensions/copilot/src/extension/chronicle/vscode-node/sessionStoreTracker.ts	Uses new extraction helpers to populate/backfill agent_name and filter summary writes.
extensions/copilot/src/extension/chronicle/node/sessionReindexer.ts	Filters summary generation during reindexing via extractPlainTextFromContent.
extensions/copilot/src/extension/chronicle/common/test/sessionStoreTracking.spec.ts	Adds unit tests for extractAgentName and extractPlainTextFromContent.
extensions/copilot/src/extension/chronicle/common/sessionStoreTracking.ts	Introduces the new extraction helpers shared by tracker and reindexer.

Copilot's findings

• Files reviewed: 5/5 changed files
• Comments generated: 2