How does Atlas detect if my OCaml `dune` build is waiting for input?

Atlas's `bash` tool races every OCaml command against a timeout. If the `dune` build times out, the `shell_metadata` block in Atlas's output explicitly states if the command was blocked on interactive input, distinguishing it from a genuinely slow process.

What OCaml-specific flags should I use if `opam` is blocked on input?

If Atlas diagnoses an `opam` command as blocked on interactive input, you should re-run it with non-interactive flags such as `-y` for "yes to all" or `--no-input` to prevent prompts, ensuring your OCaml package management proceeds without interruption.

Can Atlas help me debug a slow `dune runtest` in OCaml?

Yes, if Atlas's `bash` tool determines your `dune runtest` is genuinely slow rather than blocked, it will instruct you to retry the command with a larger timeout value in milliseconds, allowing it to complete and provide test results for your OCaml project.

How does Atlas ensure my OCaml codebase is safe from unintended changes?

Atlas employs several safety features: every tool call is permission-gated, it drafts plans in a read-only agent, computes a unified diff for all file edits, and requires your approval before writing any changes to your OCaml `dune-project` or `.ml` files.

Does Atlas understand OCaml `dune` stanzas and `.mli` files?

Yes, Atlas builds its code index by AST declarations using tree-sitter and is specifically designed to read OCaml `dune` stanzas, `.mli` interface files, and packages pinned in your `opam` switch, providing deep context for diagnosis and code generation.

What happens if I manually stop an OCaml command run by Atlas?

If you abort an OCaml command yourself, Atlas's `shell_metadata` output will clearly state "User aborted the command," distinguishing your interrupt from a timeout or a command blocked on input, providing clarity in your OCaml workflow.

Can Atlas integrate with `ocamlformat` for style consistency?

Yes, Atlas can finish its work by running `ocamlformat` on your OCaml code, ensuring that any proposed changes are style-clean and adhere to your project's formatting standards before you approve the unified diff.

Diagnose a hanging or long-running command in OCaml with Atlas in 2026

In 2026, Atlas helps OCaml developers diagnose hanging `dune` builds or `opam` scripts by racing every command against a timeout and explicitly identifying if it's blocked on interactive input or genuinely slow, guiding you to use non-interactive flags or adjust timeouts.

How Atlas Diagnoses Hanging OCaml `dune` Builds and `opam` Scripts

Atlas, in 2026, employs a robust bash tool to diagnose hanging OCaml commands by racing every execution against a predefined timeout. When a `dune` build or `opam` script exceeds this limit, Atlas provides immediate feedback, distinguishing between a command genuinely taking a long time and one silently blocked on interactive input.

Atlas, in 2026, leverages its `bash` tool to execute OCaml commands like `dune build` or `opam install`. This tool races each command against a configurable timeout. If the command exceeds this limit, Atlas immediately provides a `shell_metadata` block in its output. This block is crucial for diagnosis, as it explicitly differentiates between two common scenarios: a command genuinely taking a long time to complete, and one silently blocked on interactive input. For OCaml developers, this means no more guessing if a `dune` compilation is just slow or waiting for a prompt. Atlas's clear message guides you to the next step, whether it's adjusting a timeout or providing non-interactive flags, ensuring your OCaml development workflow remains efficient.

Identifying Blocked OCaml Commands with `dune` and `opam`

When an OCaml `dune runtest` command or an `opam` package installation appears stuck, Atlas's `bash` tool provides precise diagnostic information. For instance, a `dune` build might hang waiting for input, a common scenario in 2026 that Atlas explicitly flags in its `shell_metadata` output.

When an OCaml command, such as `dune runtest` or an `opam` package installation, appears to hang, Atlas's `bash` tool provides precise diagnostic information. For example, if `dune runtest` is blocked waiting for user confirmation, Atlas's `shell_metadata` output will explicitly call out the interactive-input case. This immediate feedback is invaluable for OCaml developers. To resolve this, Atlas instructs you to re-run the command with appropriate non-interactive flags. For `opam`, this might mean adding `-y` or `--no-input`. For `dune` commands, you might look for CI-mode flags or similar options to suppress prompts. Conversely, if the `shell_metadata` indicates the OCaml command is genuinely slow, perhaps a large `dune` project compilation, Atlas will advise retrying with a larger timeout value in milliseconds. Atlas's understanding of the OCaml ecosystem, including `dune-project` files and `opam` switches, helps it provide context-aware suggestions for your `.mli` signatures and other OCaml source files.

Ensuring Safety and Review with Atlas in OCaml Workflows

Atlas ensures a secure and transparent workflow for OCaml developers, particularly when resolving hanging commands. Every Atlas tool call, including those involving `dune` or `opam`, is permission-gated against allow, ask, and deny rules, a critical feature since its 2024 release. This prevents unintended modifications to your `dune-project` or source files.

Atlas, since its initial release, prioritizes safety and transparency in all OCaml development workflows. When diagnosing a hanging `dune` build or `opam` script, every Atlas tool call, including those that interact with your OCaml environment, is permission-gated. This means you explicitly allow, ask for confirmation, or deny actions, preventing any unexpected modifications to your `dune-project` or `.ml` source files. Before making any changes, Atlas drafts a plan in a read-only agent, allowing you to review the proposed steps. Once a plan is approved, Atlas computes a unified diff for every file edit, surfacing it for your approval before writing. This includes changes to `dune` stanzas or `.mli` signatures. Atlas also integrates with Git, reading branches, status, and diffs, and can stage and create commits on your behalf, ensuring a clean, auditable history for your OCaml projects. Finally, Atlas can finish with `ocamlformat` to ensure the diff is style-clean before you approve it, maintaining code quality and consistency.

Step by step

01Run Atlas in your OCaml workspace with a `dune-project` at the root.
02Let Atlas index your OCaml code, including `dune` stanzas, `.mli` signatures, and `opam` switch packages.
03Execute the potentially hanging OCaml command (e.g., `dune build` or `opam install <package>`) through Atlas's `bash` tool.
04Review the `shell_metadata` block in Atlas's output when the command times out, looking for explicit diagnosis.
05If Atlas indicates the OCaml command is blocked on interactive input, re-run it with appropriate non-interactive flags (e.g., `dune build --no-prompt` or `opam install <package> -y`).
06If the OCaml command is genuinely slow, retry it through Atlas's `bash` tool with a larger timeout value in milliseconds, as instructed in the `shell_metadata` message.
07If you manually aborted the OCaml command, confirm the `shell_metadata` block states "User aborted the command" to distinguish your interrupt from a timeout.
08After resolving the issue, let Atlas run `ocamlformat` to ensure style-clean diffs before approving any changes to your OCaml codebase.

Frequently asked questions

How does Atlas detect if my OCaml `dune` build is waiting for input?: Atlas's `bash` tool races every OCaml command against a timeout. If the `dune` build times out, the `shell_metadata` block in Atlas's output explicitly states if the command was blocked on interactive input, distinguishing it from a genuinely slow process.
What OCaml-specific flags should I use if `opam` is blocked on input?: If Atlas diagnoses an `opam` command as blocked on interactive input, you should re-run it with non-interactive flags such as `-y` for "yes to all" or `--no-input` to prevent prompts, ensuring your OCaml package management proceeds without interruption.
Can Atlas help me debug a slow `dune runtest` in OCaml?: Yes, if Atlas's `bash` tool determines your `dune runtest` is genuinely slow rather than blocked, it will instruct you to retry the command with a larger timeout value in milliseconds, allowing it to complete and provide test results for your OCaml project.
How does Atlas ensure my OCaml codebase is safe from unintended changes?: Atlas employs several safety features: every tool call is permission-gated, it drafts plans in a read-only agent, computes a unified diff for all file edits, and requires your approval before writing any changes to your OCaml `dune-project` or `.ml` files.
Does Atlas understand OCaml `dune` stanzas and `.mli` files?: Yes, Atlas builds its code index by AST declarations using tree-sitter and is specifically designed to read OCaml `dune` stanzas, `.mli` interface files, and packages pinned in your `opam` switch, providing deep context for diagnosis and code generation.
What happens if I manually stop an OCaml command run by Atlas?: If you abort an OCaml command yourself, Atlas's `shell_metadata` output will clearly state "User aborted the command," distinguishing your interrupt from a timeout or a command blocked on input, providing clarity in your OCaml workflow.
Can Atlas integrate with `ocamlformat` for style consistency?: Yes, Atlas can finish its work by running `ocamlformat` on your OCaml code, ensuring that any proposed changes are style-clean and adhere to your project's formatting standards before you approve the unified diff.

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