just-mcp-work

README

just-mcp-work

Just work with your workspace — over MCP.

Stop burning agent context on build files. just-mcp-work is a local STDIO MCP server: one interface to everything runnable in a workspace, handing the agent only the part it asked for.

• Run it. The task, or a plain shell command when no task fits.
• Browse instead of reading. Just, CMake, and GNU Make projects, nested anywhere in the workspace — no build file is ever loaded into context.
• One task at a time. Full metadata and parameters for the task the agent picked, and nothing around it.
• Output on demand. A run answers with a short receipt; the full stdout and stderr stay one call away, whenever the agent actually needs them.

Security

run_task executes an existing just recipe, CMake target, or Make target with arguments kept separate. run_shell_command intentionally passes command text to the operating system shell. Both run with your privileges and without a sandbox: trust the selected task or command like you trust a project's build scripts. Need isolation? Run just-mcp-work in a container. See SECURITY.md.

Install

Must be available on PATH:

• just for Just projects.
• CMake must be available for CMake projects.
• GNU Make must be available for Make projects.

Prebuilt binaries

Download an archive from the latest GitHub Release:

Platform	Download
Linux x86_64	just-mcp-work_linux_amd64.tar.gz
Linux arm64	just-mcp-work_linux_arm64.tar.gz
macOS Apple Silicon	just-mcp-work_darwin_arm64.tar.gz (opening notes)
Windows x86_64	just-mcp-work_windows_amd64.zip

Extract the matching archive and place just-mcp-work (or just-mcp-work.exe) on PATH. Verify the archive with the release checksums.txt when needed.

Sources

go install github.com/palchukovsky/just-mcp-work/cmd/just-mcp-work@latest
just-mcp-work version

Use with MCP

Run this once in the workspace to add instructions for supported coding agents. It finds the closest selected agent instruction and .mcp.json in the workspace or its parent directories. The managed instruction block and just-mcp-work MCP entry are replaced in full, leaving unrelated content and servers alone. If none exists, it creates the files in the workspace. The MCP entry uses the absolute path of the running executable, so the client does not depend on PATH:

just-mcp-work init

Run init again after updating just-mcp-work to a new version so the managed agent instructions and MCP entry are refreshed.

init does not overwrite a manually configured Codex [mcp_servers.just-mcp-work] table. Remove that table before running init so the generated managed block can take ownership of the entry.

Pass --write-mcp-config=false to print the resolved server entry instead of writing it.

The server discovers nested projects on demand. Use init --help and serve --help for agent targets and server options.

MCP tools

Tool	Purpose
list_projects	List filtered projects and runner errors.
list_tasks	List tasks, parameters, and duration statistics.
run_task	Run a task, promoting a long run to the background.
start_task	Start a selected task asynchronously.
run_shell_command	Run a shell command; long runs go to background.
start_shell_command	Start a shell command asynchronously.
get_run	Read stored run metadata.
get_run_logs	Page stdout or stderr by byte offset.
get_run_status	Read run liveness, output, and duration statistics.
wait_run	Wait for completion without killing a run on a wait timeout.
stop_run	Stop a running task owned by this server.
list_runs	List recent runs, newest first, with the scanned count.
version_status	Compare this binary with the latest stable GitHub tag.

list_projects defaults to the workspace root at depth 1 and skips dot-directories. Use path to choose a subtree, max_depth (-1 is unlimited) or include_hidden to widen directory coverage, and runners to restrict projects. applied_filter.pruned.depth and .hidden count skipped directory subtrees; .runner_mismatch counts inspected projects removed by runners. excluded reports directories skipped by the operator's policy and cannot be widened. This filtering applies only to the list: list_tasks and task tools can still address any discovered workspace project.

Task IDs are runner-qualified, for example just:build, cmake:build:debug, or make:test. Make projects expose their explicit targets without running recipes during task discovery. For a short task, use run_task; it waits for up to max_wait_ms, --sync-deadline, or JMW_SYNC_DEADLINE (in that precedence order). A receipt with status: "running", completed: false, and promoted: true is successful handoff to a background run, not a failure: use its run_id with wait_run or get_run_status and do not run the task again. Use start_task up front for a task with a long historical average.

When an MCP client supplies a progress token, synchronous task calls publish the run_id immediately and report elapsed time, output age, and byte counts every 10 seconds. get_run_status, wait_run, and list_tasks expose duration statistics derived from retained run metadata; aborted runs are counted but do not affect duration averages. last_output_age_ms is the anti-hang signal.

list_runs returns a bounded page of newest ledger entries. It reports scanned and, when truncated is true, a next_cursor for the next page, so filters cannot silently hide matching older runs.

run_shell_command is separate from project discovery: it accepts command text and an optional workspace-relative working_directory (default .), so it can run from directories that have no Just, CMake, or Make project. It uses the current OS shell ($SHELL, falling back to /bin/sh, on Unix; ComSpec on Windows). The working directory must exist inside the workspace and cannot be a symlink.

get_run_status is non-blocking. wait_run waits up to max_wait_ms (30s by default); set it to 0 for an immediate snapshot. Status tools return 4096 tail bytes by default; set tail_bytes to 0 when output is not needed.

Each task has a 15-minute timeout by default. Set --timeout=0 or JMW_TIMEOUT=0 to disable that timeout entirely; no task timer is created in that mode. The selected timeout is recorded with the run, so a later server configuration cannot misreport a foreign run's deadline.

Configuration

Flag	Environment	Default
--root	JMW_ROOT	Current directory
--timeout	JMW_TIMEOUT	15m (0 disables the timeout)
--sync-deadline	JMW_SYNC_DEADLINE	1m
--retention	JMW_RETENTION	72h
--exclude	—	None

Run data is kept under .just-mcp-work/log/ in the selected workspace.

Development and release

With Just:

just install-lint
just verify
just build-all
just package

just verify checks formatting, dependencies, strict lint, vet, race-enabled tests, build, and the MCP smoke flow. just build-all produces Linux, macOS, and Windows binaries; just package creates the release archives and checksums.

just release patch|minor|major verifies the project, creates and pushes the next tag, then GitHub Actions builds and publishes the release. Use just release-dry [patch|minor|major] to run the same checks and start a pipeline dry run without creating a tag. The dry run needs authenticated GitHub CLI access.

License

MIT