`ReadBeforeWriteSandbox` blocked writes to any existing file the agent
had not read, tracked by a session read set populated only by
`read_file`, `grep`, `read_many_files`, and the Kimi `Read`.
The gpt56 profile has none of those. It mirrors Codex's tool contract --
`shell_command`, `apply_patch`/`edit_file`, `update_plan`, `web_search`
-- and reads through the shell, so its read set stayed permanently
empty and every edit to an existing file failed. In run
01KYD4360GN6SED4BYEVGYP4XT all 28 `edit_file` calls failed, 25 of them
on the guard. The agent read `package.json` with `sed` and `cat`,
hex-dumped it trying to diagnose the rejections, then routed around the
guard with `sed -i`, which the guard never covered. It prevented no
blind write; it converted content-anchored edits into an unreviewed
in-place shell rewrite.
Neither Codex nor Kimi Code enforces read-before-write at runtime.
Codex's `apply_patch` `Add File` overwrites an existing path silently;
Kimi Code's `Write` has no check at all. Both rely on the exact-match
requirement in their edit tools, which is stronger proof of inspection
than a read set, plus per-write approval.
Tool descriptions and the Kimi prompt keep telling the model to read
before editing -- that guidance matches Kimi Code's own `edit.md` and
still prevents `old_string not found` -- but no longer claim the
workspace refuses unread writes.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Extend the Daytona Bash probe to cover the streaming toolbox-session transport in addition to the direct process exec. The two build different requests, so passing one is not evidence for the other: the `exec` regression fixed in #636 left every streaming command stalling until its timeout while the lifecycle probe reported a healthy sandbox. The session probe reuses the streaming path's own command construction and completion wait, so a transport that suppresses Daytona's exit-code bookkeeping fails at the lifecycle boundary with a remediation that names the wrapper-shell contract.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Run the streaming Bash wrapper as a child of Daytona's session shell so the provider can resume its bookkeeping and persist the command exit code. Add a regression test that exercises the sourced-command contract and preserves a nonzero exit status.
Fabro advertised Bash while its three backends implemented three
different contracts: Daytona evaluated commands through `sh`, and
Docker's streaming, stdio, and setup paths used a login shell. Bash-only
syntax silently misbehaved depending on provider and code path, and
login profiles could change PATH and command behavior per image.
Make `bash -c` the enforced interpreter for every command string the
Unix sandbox API accepts, on every production backend and through both
buffered and streaming execution. This selects the interpreter only —
no `errexit`, no `pipefail`, no login mode — so `false | true` still
succeeds and a workflow that wants other semantics writes them into its
own command.
Local resolves `bash` through the worker's PATH (NixOS has no
/bin/bash) and reuses that one executable across all three command
paths. Docker and Daytona require /bin/bash with no `sh` fallback.
Fresh initialization and resume/start now verify Bash through a shared
marker-validating probe before reporting the sandbox usable, so a
missing or non-Bash interpreter fails at the lifecycle boundary with
provider-specific remediation instead of on the first command. The
probe also rejects Bash in POSIX mode, which an image whose `bash` is
really `sh` would otherwise pass.
Sandbox MCP scripts and the detached launch wrapper move under the same
contract; host-side stdio MCP scripts, hooks, and interactive terminals
are separate executors and keep their existing `sh` behavior.
The `shell` tool's name and JSON schema are unchanged across providers;
only its prose now identifies `command` as Bash source.
BREAKING CHANGE: sandbox commands no longer load login-shell profiles,
so environment set in /etc/profile.d/*.sh, ~/.bash_profile, or
nvm/rbenv/sdkman initializers is gone. Move those exports into the
Dockerfile's ENV or the Daytona snapshot image.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The shell executor rendered every returned ExecResult and returned
Ok(output), so nonzero exits, timeouts, and cancellations reached
execute_one_tool() as successes. That false ToolResult propagated
consistently: agent.tool.completed recorded is_error: false, the success
post-tool hook ran, Anthropic saw is_error: false, OpenAI Responses saw a
completed function-call output, and CLI/web rendered a successful tool
call.
ExecResult::is_success() is now the authoritative predicate. The executor
runs through exec_command_streaming() with a sink callback, so it keeps
the production providers' stream provenance and partial-output capture,
and drops the exec 2>&1 prefix that merged stderr into stdout before
Fabro could report it. Model-facing text labels termination, exit code,
duration, and either separate stdout/stderr sections or one combined
section when the provider cannot separate streams.
Session-bound dispatch also emits a typed agent.tool.process.completed
event carrying the process metadata, streams_separated, and bounded
redacted output tails. It is subordinate diagnostic data: the following
agent.tool.completed remains the one tool-protocol completion and the
authoritative owner of is_error, so consumers need no new row.
Nonzero, timed-out, and cancelled commands intentionally change from
successful to failed tool results, and PostToolUseFailure replaces
PostToolUse for them. On Docker the agent shell tool now uses the
streaming path's bash -lc supervisor, which terminates the process group
on timeout instead of leaving container-side processes running.
The public shell schema is unchanged and pinned by an exact assertion.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
