Best possible solution:

Land this after redacted live E2B proof shows --keep --lease-output writes a usable handle and the emitted cleanup command releases the sandbox, while keeping the change scoped to the provider adapter, tests, and docs.

Do we have a high-confidence way to reproduce the issue?

Not applicable: this is a feature PR, not a bug report. The current-main check is source-based: E2B does not advertise FeatureRunSession and --lease-output is gated before this PR.

Is this the best way to solve the issue?

Unclear until live proof: the code follows the existing provider-adapter pattern, but advertising the capability should wait for redacted real E2B run/cleanup output and maintainer acceptance.

AGENTS.md: found and applied where relevant.

Codex review notes: model internal, reasoning high; reviewed against 943798f62935.

Label changes:

• add P2: This is a normal provider capability improvement with real orchestration value but limited blast radius and a proof gate before merge.
• add rating: 🧂 unranked krab: Overall readiness is 🧂 unranked krab; proof is 🧂 unranked krab and patch quality is 🐚 platinum hermit.
• add status: 📣 needs proof: The PR needs real behavior proof before ClawSweeper can clear the contributor ask. Needs real behavior proof before merge: The PR body provides unit/docs checks but no live E2B --keep --lease-output run, cleanup command output, or redacted runtime log proving the after-fix provider path. After adding proof, update the PR body; ClawSweeper should re-review automatically. If it does not, the PR author or someone with repository write access can comment @clawsweeper re-review.

Label justifications:

• P2: This is a normal provider capability improvement with real orchestration value but limited blast radius and a proof gate before merge.
• rating: 🧂 unranked krab: Overall readiness is 🧂 unranked krab; proof is 🧂 unranked krab and patch quality is 🐚 platinum hermit.
• status: 📣 needs proof: The PR needs real behavior proof before ClawSweeper can clear the contributor ask. Needs real behavior proof before merge: The PR body provides unit/docs checks but no live E2B --keep --lease-output run, cleanup command output, or redacted runtime log proving the after-fix provider path. After adding proof, update the PR body; ClawSweeper should re-review automatically. If it does not, the PR author or someone with repository write access can comment @clawsweeper re-review.

What I checked:

• Repository policy read: AGENTS.md was read fully; its provider-adapter boundary guidance is relevant because the PR keeps the new capability inside the E2B adapter plus docs/tests rather than adding provider-specific core routing. (AGENTS.md:1, 943798f62935)
• Current main gates E2B lease output: On current main, E2B advertises only FeatureURLBridge, and run rejects --lease-output unless the provider advertises FeatureRunSession. (internal/providers/e2b/provider.go:24, 943798f62935)
• Current E2B lifecycle is source-auditable: Current main already has E2B acquire/reuse identity, shouldStop := acquired && !req.Keep, deferred cleanup, and keep-on-failure hooks, which are the lifecycle points this PR wires into a session handle. (internal/providers/e2b/backend.go:125, 943798f62935)
• PR diff scope: The PR changes five files: E2B backend/provider/core alias, E2B tests, and the provider matrix; it adds session construction after lease identity exists and a quoted E2B cleanup command helper. (internal/providers/e2b/backend.go:150, 4d870e2f6df1)
• Related tracker context: The linked provider-adoption tracker remains open and its latest human audit lists E2B as ready for a small per-provider run-session PR, while still requiring provider lifecycle proof before advertising the feature.
• Proof and checks: The PR body lists go test ./internal/providers/e2b ./internal/providers/all, scripts/check-docs.sh, and git diff --check, and GitHub reports CI checks passing, but no live E2B --keep --lease-output run or cleanup/list output is attached. (4d870e2f6df1)

Likely related people:

• zozo123: Yossi Eliaz authored the original E2B provider commit and later authored the merged Islo run-session implementation that this PR pattern follows; they also contributed the linked tracker audit naming E2B as ready. (role: introduced E2B provider and adjacent run-session contributor; confidence: high; commits: 1b6397871cb4, c7f1c55772b4; files: internal/providers/e2b/backend.go, internal/providers/e2b/provider.go, internal/providers/islo/backend.go)
• steipete: Peter Steinberger authored recent main commits touching the relevant provider/run surfaces in this checkout and posted the tracker status refresh requiring provider lifecycle proof before advertising run-session. (role: recent area contributor and reviewer-context source; confidence: medium; commits: 943798f62935, 008f70f30614; files: internal/providers/e2b/backend.go, internal/cli/run.go, internal/cli/provider_backend.go)
• RomneyDa: Dallin Romney authored the original Blacksmith lease-output work that introduced the generic RunSessionHandle and FeatureRunSession contract this E2B PR extends. (role: introduced generic run-session contract; confidence: medium; commits: 76829952a9d8; files: internal/cli/provider_backend.go, internal/cli/run.go)

• 🦀 challenger crab: rare, exceptional readiness with strong proof, clean implementation, and convincing validation.
• 🦞 diamond lobster: very strong readiness with only minor maintainer review expected.
• 🐚 platinum hermit: good normal PR, likely mergeable with ordinary maintainer review.
• 🦐 gold shrimp: useful signal, but proof or patch confidence is still limited.
• 🦪 silver shellfish: thin signal; proof, validation, or implementation needs work.
• 🧂 unranked krab: not merge-ready because proof is missing/unusable or there are serious correctness or safety concerns.
• 🌊 off-meta tidepool: rating does not apply to this item.

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