OneAgent for VS Code 0.5.20 pre-release

OneAgent is an agent-first VS Code workbench that lets the authoritative Codex app-server inspect and edit local files, run commands and tests, operate tools, request input or approvals, and resume durable threads.

Version 0.5.20 keeps the responsive Projects sidebar and adds cross-IDE stale-session recovery plus a fail-closed non-empty model gate. A deleted Runtime session is removed from local navigation without leaving the workbench Connecting, and conversations created during startup refresh and share the entitled model catalog before sending. This extension-only update keeps using the same verified Runtime artifacts and does not require a Runtime reinstall. No OpenAI API key or Gateway bearer token is stored in the extension or OneAgent Home.

Preview availability is currently limited to invited Ampacs pilot users on Windows 11 or Local WSL2 (Ubuntu LTS x64) with VS Code Stable. Ampacs Remote WSL over SSH remains a post-Marketplace pilot lane until its server topology is validated. The 0.5.x Windows pilot Host is pinned to the exact release version and SHA-256 but is not yet Authenticode signed, so Windows or endpoint-security warnings may occur. The extension fails closed when the exact runtime signature, Host, managed Codex runtime, platform, or tenant entitlement is unavailable.

Work locally with a governed company agent

• Ask OneAgent to inspect a repository, edit files, run commands and tests, and operate local developer tools.
• Follow live progress without filling the task with raw command output. On completion, Worked for <duration> stays available above the final reply.
• Attach files, images, the current editor selection, or a folder path. Mention workspace files and installed Skills with @.
• Open file references in the editor, review every changed file in native VS Code diffs, or undo the turn when its snapshot is still safe.
• Choose Ask for approval, Workspace, or Full access. Workspace uses Codex's native on-request + workspace-write policy; OneAgent does not add a second approval engine.

Search and resume local tasks without leaving the OneAgent panel:

Use Default or Plan mode with tenant-approved Fast, Balanced, and Deep presets:

Requirements

• Windows 11 local or WSL2 with Ubuntu LTS x64, and VS Code Stable 1.105.0 or newer for the 0.5.x pilot. WSL1, Linux ARM64, Dev Containers, virtual workspaces, and macOS are not supported in this release.
• An invited OneAgent company account and an entitled tenant profile.
• A OneAgent Runtime explicitly compatible with the installed extension. After sign-in, Marketplace 0.5.20 offers Install OneAgent Runtime when the Host, managed Runtime or required Code Mode Host is missing; download and signature/digest verification start only after the user chooses it. Windows then requests UAC; WSL2 installs into the current Linux user's XDG directories without elevation. The invited 0.5.x pilot uses the exact SHA-256-pinned unsigned Host; Authenticode signing is mandatory beginning with 0.6.0 stable.
• A trusted local filesystem workspace, or the profile-scoped OneAgent scratch workspace used when no folder is open. Virtual and untrusted workspaces do not start the Agent runtime.

After installing the extension, open the OneAgent Activity Bar view, choose Sign in to OneAgent, and finish the PKCE login in your browser. The returned tenant profile selects the isolated local Agent Home and Gateway runtime. If the runtime is missing, choose Install OneAgent Runtime, review the exact Host and Codex release and accept Windows UAC. Login alone never installs native software.

Runtime boundary

VS Code
  -> OneAgent extension and thin protocol adapter
  -> OneAgent Host over process-bound local transport
       -> validate Tenant Profile, user allowlist, Agent Bundle and release mode
       -> select tenant/user profile and isolated OneAgent Home
       -> start the pinned codex app-server with CODEX_HOME=<profile>/agent-home
       -> keep short-lived Gateway credentials in memory
  -> codex app-server (Windows or Linux, matching the workspace Extension Host)
       -> authoritative thread, turn, reasoning, tools, approvals and file changes
       -> local PowerShell, Git, filesystem, build, test and application operations
       -> OneAgent Gateway by default, or an explicit Codex-account development fallback
  -> OneAgent Gateway
       -> token-bound tenant/user/device identity
       -> model entitlement, request limits and metadata-only audit
       -> OpenAI Responses API using server-held credentials

The extension and Host do not add a second planner, semantic router, tool loop, transcript or ordinary local approval layer.

Ampacs development tenant

The bundled development fixture activates:

tenant: ampacs
user: <configured-development-user>
profile_key: <opaque-profile-key>
OneAgent Home: %LOCALAPPDATA%\OneAgent\Agent\profiles\<profile_key>\agent-home

The Host validates the user allowlist before launching app-server. Different tenant/user pairs receive different opaque profile keys and cannot share thread, SQLite, cache, receipt or diagnostic roots.

Unsigned Tenant Profiles are accepted only when oneagent.environment=development. Staging and production require signed profiles, a native Host and a promoted release digest. Normal releases also require an allowed Authenticode signer; only the 0.5.x Marketplace preview for tenant ampacs may use the explicit hash-pinned unsigned Host exception.

oneagent.authProvider defaults to oneagent. Set it to codex only when intentionally testing the local Codex-account fallback; staging and production always enforce OneAgent Identity regardless of that setting.

Implemented experience

• Searchable and resumable threads, sticky editable title, new-thread and settings actions.
• Streaming commentary, reasoning summaries, plans, commands, output, tools, file changes and final replies.
• Frame-batched incremental token rendering without rebuilding historical turns; collapsed command output is mounted only when opened and retained output is bounded to the latest 256 KB per activity.
• Collapsed Worked for <duration> activity before the final reply with nested commands.
• Safe Markdown, code-style tables and clickable file references.
• File, folder-path, current-selection and image attachments.
• Grouped @ Files and Skills suggestions.
• Agent/Plan, model, reasoning effort and service-tier selection.
• OneAgent production presets: Fast (gpt-5.6-luna, high), Balanced (gpt-5.6-terra, medium, default), and Deep (gpt-5.6-terra, high); Standard service tier for all three.
• Refined dark OneAgent assets for the Activity Bar, Webview welcome state and packaged extension icon.
• Codex-native request-input and approval flows with Ask first, Workspace and Full access modes.
• Turn-level change summaries, native VS Code diff review and SHA-guarded Undo.
• Host-supervised app-server, isolated OneAgent Home, Tenant Profile/Bundle verification and crash propagation.
• PKCE OneAgent Identity client with SecretStorage-backed refresh sessions.
• Responses-compatible OneAgent Gateway with JWT verification, tenant/user/model entitlement, request-size limits, rate buckets, streaming pass-through and metadata-only audit.
• Windows Node SEA build for oneagent-agent-host.exe and standalone Linux x64 Host plus managed Codex runtime candidate packaging.
• Platform-aware Runtime Release V2 delivery, signed manifest validation, device-bound download receipts, bounded extraction, atomic activation and rollback metadata for Linux x64.

Build and verify

Set-Location <path-to-one-agent-vscode>
pnpm install --frozen-lockfile
pnpm run check
pnpm run smoke:agent-host
pnpm run build:native-host
pnpm run smoke:native-host
pnpm run build:linux-runtime:candidate # run from Linux x64/WSL2
pnpm run package

The Host smoke tests use a disposable data root and verify the app-server reports the Host-selected isolated CODEX_HOME. They do not copy or print the user's normal Codex credentials.

Validate in VS Code

Install the exact pre-release candidate:

code --install-extension .\dist\oneagent-vscode-0.5.20.vsix --force

Then:

1. Run Developer: Reload Window.
2. Open the OneAgent Activity Bar icon.
3. Confirm the account action says Sign in to OneAgent and opens https://identity.one-agent.ai.
4. Sign in with an Ampacs-authorized OneAgent user. If the Host is missing, choose Install OneAgent Runtime. Accept Windows UAC on Windows; WSL2 installs per-user without elevation. This installs both Host and Codex; do not install the OpenAI extension.
5. Confirm the returned Tenant Profile selects the isolated Ampacs OneAgent Home and Gateway runtime.
6. Run a read-only repository question, Plan mode, a disposable file edit/test, Review and Undo.
7. Confirm logs show OneAgent Host ready, the Ampacs tenant and an isolated profile under %LOCALAPPDATA%\OneAgent\Agent on Windows or ${XDG_STATE_HOME:-$HOME/.local/state}/OneAgent/Agent in WSL2.

Privacy, support and security

• Privacy policy
• Support and troubleshooting
• Security policy
• Release notes
• Terms of use

Production promotion boundary

The source contracts, OneAgent Identity, signed production Tenant Profile and Agent Bundle, Gateway, shared quota state and canonical production ingress are implemented and deployed. The 0.5.20 pre-release retains the explicit, entitled Host plus managed Runtime bootstrap flow backed by a private immutable artifact and exact digest verification. Stable production promotion still requires the OneAgent Windows code-signing certificate, promotion of the GCP KMS runtime-release public key and signed Linux artifact, signed update/rollback acceptance, clean-user Local WSL agent-loop evidence, Ampacs pilot evidence and a second-tenant security proof.

Marketplace builds default to oneagent.environment=production. The extension intentionally fails closed when the signed Host trust artifacts are absent.