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 previous commit introduced render_prompt and splice_optional_section, a
second templating mechanism in a workspace that already standardizes on
MiniJinja behind fabro-template. Drop both and render the profile prompts the
same way fabro-workflow and fabro-manifest render theirs.
Expressing the conditionals as {% if %} lets every profile collapse to a single
template, since the optional blocks no longer need to be separate files spliced
in from Rust:
before: 6 files + 2 splice helpers, prompt prose split across .md and .rs
after: 3 files, one per profile, all prose in the template
Rust now passes only facts -- provider name, which file-edit tool is active,
and whether web search and subagents are available. Values land under `vars`,
so templates read {{ vars.env_block }}. Booleans are passed as "true"/"false"
and compared explicitly via the bool_var helper, because the shared
TemplateContext types vars as strings and a bare {% if %} on the string
"false" would be truthy.
Also converts fabro-server's Ask Fabro prompt, which is assembled at runtime.
Its tool guidance now arrives as a template variable instead of being
interpolated into the template text. That guidance carries tool names and
descriptions that can originate from MCP servers, and MiniJinja does not
re-render substituted values, so a tool description containing {{ ... }} stays
inert rather than being evaluated.
Output is unchanged. Verified by diffing all ten prompt variants against the
same unmodified origin/main worktree used for the previous commit.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
