Release 0.12.1

[blove]

Release 0.12.1

This prepares the fixed group of 21 B4.run packages at 0.12.1 from main c0754368d. Both charts' appVersion moves to 0.12.1 (b4-app chart 0.2.21, b4-sandbox-infra chart 0.1.25). All 14 pending changesets are patch, so this is a plain pnpm run version (changeset version plus the chart sync) with no hand retarget. The result is byte-identical to the bot's Version Packages branch (#818 at 222a0e92). This release is cut from its own branch because the bot force-pushes that branch on every push to main.

What ships

• Workspaces: editFile tool and ranged readFile; staged workspaces (sandbox.stagedWorkspaces, source upload plus workspace on POST /threads); read a thread's workspace over HTTP (sandbox.workspaceRead: "http").
• Per-thread sandbox and permissions: sandbox.thread decides each thread's workspace, image and policy once at first admission. A thread can have its own permission allow-list and keeps "Always" grants on the thread's record.
• Performance: batched workspace inspection for the Docker and Kubernetes backends (143 s → about 1 s over about 1.2k entries). Managed workspaces verify the source bundle once per session, not before every call.
• Security fix: the node build target now carries the thread access policy in its build. A missing policy file at boot refuses to start instead of serving thread endpoints ungated.
• Testing: responseSchema on createAgentHarness/defineEval; recordings that replay would reject now fail at record time; aimock ^1.43.0.
• Fixes: a Docker command that exits before reading stdin no longer crashes the process with EPIPE. The sandbox network default is now honest: { mode: "allow" } with no unenforced denylist.

Verification

• 21/21 publishable packages are at 0.12.1. No changeset files remain.
• Run locally on Node 24, all passed: pnpm build, node scripts/check-docs.mjs (which scans the generated CHANGELOGs), pnpm test:release-integrity, pnpm test:sync-chart-appversion, and pnpm verify:typescript-tooling-pack (smoke passed at 0.12.1).
• CI on main at the base commit c0754368d passed (CI, CodeQL, Release).

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Project	Deployment	Actions	Updated
b4-run	Ready	Preview	Sep 25, 2026 10:10pm UTC

[github-actions]

Automated approval: this PR received an intelligent (AI) code review. See the review comments on this PR.

[blove]

Superseded by the 0.13.0 release PR: Brian asked for a minor release instead of 0.12.1.