Split session artifacts into artifacts and references

[Benjamin Christopher Simmonds (benibenj)]

An artifact is something the session produced that is not an ordinary workspace edit: a pull request or issue it opened, a plan file written outside the workspace, another side effect of its work. A reference is something it did not produce but the user should look at because of the task: the pull request or commit that introduced a bug, a relevant page.

The agent now says which it recorded through a mandatory isArtifact flag, so the tools are renamed to add_artifact_or_reference, remove_artifact_or_reference and list_artifacts_and_references, and the per-type createdByThisSession field is gone — being produced by the session is the definition of an artifact. Entries persisted before this change read back as artifacts. Tool calls render "Added artifact" or "Added reference" from the flag; removal takes its wording from what it actually removed.

References get their own pill, always summarized as a count, placed directly after the artifacts pill so the two read as a pair. Only artifacts are promoted into the pull request and issue pills, which poll GitHub, but a reference keeps its link identity so anything those pills already show is offered exactly once.

Along the way

• The artifacts pill no longer collapses into a lone entry unless it is a file, whose name and themed icon say what it is; every other single artifact stays behind "1 Artifact" so the row keeps a stable shape. alwaysSummarize becomes a ChatPillSingleEntry policy interpreted in one place.
• Parsing GitHub issue and pull request references out of user messages is removed. It fed the same pills from a second source, which would show a recorded reference twice, and it guessed at intent the agent can now state outright.
• A uri the client cannot open is rejected when it is recorded, instead of being reported as added and then appearing in no pill at all.
• Reading persisted artifacts reports what it could not parse, so a corrupt row no longer empties a session's artifacts without a trace.

Notes

• The new SessionChatPills_ReferenceSingle and SessionChatPills_ArtifactsAndReferences fixtures need a screenshot baseline from CI.
• One consequence of the compatibility rule, called out deliberately: a pull request persisted before this change with createdByThisSession: false reads back as an artifact and can therefore become the session's main pull request. It only affects sessions that recorded someone else's pull request.

Validation

tsc --noEmit, eslint over every changed file, valid-layers-check, and the affected node and chromium suites all pass.

[vs-code-engineering]

📬 CODENOTIFY

The following users are being notified based on files changed in this PR:

Ladislau Szomoru (@lszomoru)

Matched files:

• src/vs/sessions/services/sessions/common/session.ts

[Copilot]

Pull request overview

Splits session-produced artifacts from task references across storage, tools, GitHub promotion, and chat pills.

Changes:

• Adds mandatory isArtifact classification and separate References UI.
• Renames artifact server tools and removes message-based GitHub reference parsing.
• Adds persistence diagnostics, URI validation, tests, and fixtures.

Show a summary per file

File	Description
sessionChatInputToolbar.fixture.ts	Adds artifact/reference fixtures.
chatTurnPills.test.ts	Tests single-artifact rendering.
chatTurnPills.ts	Configures artifact summary policy.
chatDropdownPill.ts	Introduces single-entry policies.
session.ts	Adds isArtifact to session entries.
localAgentHostSessionsProvider.test.ts	Tests GitHub promotion behavior.
baseAgentHostSessionsProvider.ts	Promotes only produced GitHub entries.
agentHostSessionArtifacts.ts	Partitions artifacts and references.
sessionChatPills.test.ts	Tests References visibility.
sessionArtifacts.test.ts	Updates artifact fixtures.
sessionChatPills.ts	Registers the References pill kind.
sessionCustomizations.ts	Adopts the summary policy enum.
sessionChatInputToolbar.ts	Adds and positions References.
sessionArtifacts.ts	Builds separate artifact/reference sections.
chatContributions.test.ts	Removes obsolete parsing tests.
artifactServerTools.test.ts	Tests renamed tool displays.
agentSideEffects.test.ts	Removes reference-parsing coverage.
agentHostPullRequestOperationProvider.test.ts	Updates Git service mock.
agentHostMergeOperationProvider.test.ts	Updates Git service mock.
agentHostGitStateService.test.ts	Removes message parsing tests.
agentHostContributions.test.ts	Updates Git service mock.
agentHostChangesetOperationService.test.ts	Updates Git service mock.
agentHostChangesetCoordinator.test.ts	Updates Git service mock.
sessionTestHelpers.ts	Updates no-op Git service.
sessionArtifacts.test.ts	Tests classification and persistence parsing.
githubPullRequestReferences.test.ts	Removes deleted parser tests.
githubIssueReferences.test.ts	Removes text parser tests.
artifactServerTools.ts	Renames and expands artifact tools.
githubReferencesContribution.ts	Stops parsing outgoing messages.
agentService.ts	Logs persisted artifact corruption.
agentHostGitStateService.ts	Removes GitHub text parsing.
sessionState.ts	Removes parsed issue-reference state.
sessionArtifacts.ts	Persists and parses classification.
sessionArtifactCollection.ts	Validates classified tool input.
serverToolNames.ts	Renames artifact tool identifiers.
githubPullRequestReferences.ts	Deletes the PR text parser.
githubIssueReferences.ts	Retains URL-only issue parsing.
agentHostGitStateService.ts	Removes reference attachment API.

Review details

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Suppressed comments (1)

src/vs/platform/agentHost/common/sessionArtifacts.ts:155

• readSessionArtifacts accepts rows that lack their kind-specific payload (for example, a file without uri or a pull request without link). Such a row makes dropped remain zero here, then toSessionArtifact silently removes it on the client, so the new corruption warning still misses malformed persisted entries. Validate the required fields per artifact type before computing dropped.

	const artifacts = readSessionArtifacts({ [SESSION_META_ARTIFACTS_KEY]: raw });
	return { artifacts, dropped: raw.length - artifacts.length };

• Files reviewed: 38/38 changed files
• Comments generated: 4
• Review effort level: Balanced

[github-actions]

Screenshot Changes

Base: 79ee2233 Current: ae280e32

Changed (2)

sessions/sessionChatInputToolbar/SessionChatPills_ArtifactSinglePullRequest/Dark

Before	After

sessions/sessionChatInputToolbar/SessionChatPills_ArtifactSinglePullRequest/Light

Before	After

Added (4)

sessions/sessionChatInputToolbar/SessionChatPills_ReferenceSingle/Dark

sessions/sessionChatInputToolbar/SessionChatPills_ReferenceSingle/Light

sessions/sessionChatInputToolbar/SessionChatPills_ArtifactsAndReferences/Dark

sessions/sessionChatInputToolbar/SessionChatPills_ArtifactsAndReferences/Light