infra/AGENTS.md

AGENTS.md

Guidance for agentic coding tools working in this repository. Project type: Ansible-based infrastructure and user dotfiles.

Repository snapshot

• Entry playbook: ansible/site.yml
• Inventory: ansible/inventory/hosts.yml
• Group vars: ansible/inventory/group_vars/*.yml
• Host vars: ansible/inventory/host_vars/*.yml
• Templates: ansible/templates/**/*.j2
• Dotfiles source of truth: dotfiles/
• Utility scripts: scripts/
• Sensitive material/examples: secrets/

Active orchestration

ansible/site.yml currently applies:

• all -> dotfiles_common
• void -> packages_void, services_runit, profile_desktop_i3
• ubuntu_workstation -> packages_ubuntu, services_systemd, profile_workstation_gnome
• ubuntu_server -> packages_ubuntu, services_systemd, profile_server

Active roles:

• dotfiles_common, packages_void, services_runit, profile_desktop_i3, packages_ubuntu, services_systemd, profile_workstation_gnome, profile_server

Roles present but not wired into ansible/site.yml:

• base
• dotfiles

Local instruction files

Checked in this repository when this file was written:

• .cursorrules: not present
• .cursor/rules/: not present
• .github/copilot-instructions.md: not present If any of these appear later, treat them as higher-priority local instructions.

Working assumptions

• Favor idempotent, host-safe changes over cleverness.
• Preserve the layering: all -> OS -> profile -> host.
• Validate on one host before broad rollout.
• Prefer minimal, targeted edits over cleanup refactors.
• Treat secrets/ as sensitive and avoid exposing values.
• dotfiles/common/.tmux/plugins/ contains vendored upstream code.

Build, lint, and test commands

There is no compile/build step. Validation is based on syntax checks, inventory inspection, dry-runs, and linting.

Install tooling if needed:

python3 -m pip install ansible
ansible-galaxy collection install community.general

Linting and static checks if available locally:

ansible-lint ansible/site.yml
ansible-lint ansible/roles
yamllint ansible/
sh -n scripts/bootstrap_mail.sh
shellcheck scripts/bootstrap_mail.sh

Single-test equivalents

There is no Molecule, pytest, or dedicated unit-test suite. Use the narrowest validation that matches the change.

Fastest confidence check:

ansible-playbook ansible/site.yml --syntax-check

Best default dry-runs:

ansible-playbook ansible/site.yml --limit ikaros --check --diff
ansible-playbook ansible/site.yml --limit deadalus --check --diff
ansible-playbook ansible/site.yml --limit prometheus --check --diff

Testing notes:

• Prefer --limit aggressively to avoid accidental multi-host rollout.
• Prefer --check --diff before package, service, PAM, bootloader, firewall, or session changes.
• Keep task names stable and unique enough for --start-at-task.
• If you change only vars, inventory inspection may be the quickest useful check.

Code style guidelines

General principles

• Keep orchestration in playbooks and implementation details in roles.
• Prefer declarative modules over imperative commands.
• Avoid unrelated refactors while solving a targeted task.
• Preserve idempotency and make state transitions explicit.

Ansible modules and task structure

• Use FQCN module names such as ansible.builtin.copy and community.general.ufw.
• Prefer purpose-built modules over ansible.builtin.command or ansible.builtin.shell.
• Use command only when no good module exists; use shell only when shell features are required.
• When using command or shell, set changed_when and failed_when when defaults are misleading.
• Keep task names imperative, outcome-based, and unique enough for --start-at-task.
• Tag every task consistently with its execution flow, typically packages, services, dotfiles, gnome, nvidia, or dotfiles:*.
• Prefer loop with clear loop_control.label for user-facing collections.

YAML formatting

• Start YAML files with ---.
• Use 2-space indentation and never tabs.
• Keep keys, lists, and maps in stable order.
• Quote file modes as strings: "0644", "0755", "0600", "0700".
• Avoid formatting-only churn in untouched sections.

Variables, types, and naming

• Use snake_case consistently for variables and facts.
• Follow existing families such as common_packages, profile_packages, host_packages, common_dotfiles, workstation_dotfiles, server_dotfiles, and host_dotfiles.
• Keep booleans as booleans, not quoted strings.
• Keep structured data as YAML collections, not comma-separated strings.
• Guard optional collections/maps with default([]) and default({}).
• Guard optional strings with default('').
• Build user paths from {{ user_home }} instead of hardcoding home directories.
• Host-specific overrides belong in host_vars, not shared group files.

Error handling and safety

• Guard OS-specific or profile-specific behavior with when clauses.
• Prefer explicit inputs over assumptions about host state.
• Use failed_when: false only for intentional probes or best-effort detection.
• Use no_log: true for secrets, passwords, and sensitive command results.
• Keep tasks non-interactive and automation-safe.
• Avoid destructive operations in user homes unless clearly required.
• Fail early with ansible.builtin.fail when prerequisites such as architecture, release metadata, or session bus data are missing.
• For firewall changes, allow required access before enabling the firewall.

Shell, scripts, and external code

• Prefer POSIX sh for simple scripts; use Bash only when Bash features are required.
• Quote variable expansions unless intentional word splitting is required.
• Preserve executable bits for deployed scripts where appropriate.
• If you add Python later, follow standard-library, third-party, local import grouping.
• Treat vendored tmux plugins as upstream code unless the task explicitly targets them.

Editing guidance by area

• ansible/site.yml: keep it small and orchestration-focused.
• ansible/inventory/group_vars/*.yml: shared defaults by layer.
• ansible/inventory/host_vars/*.yml: host-specific overrides only.
• ansible/roles/*/tasks/main.yml: role implementation details.
• ansible/templates/**/*.j2: keep secrets and host-specific values parameterized.
• dotfiles/: user-facing config and session scripts deployed by roles.
• scripts/: standalone local utilities; keep them safe to run manually.

Validation expectations before finishing

Run the narrowest useful checks for the area you changed.

Default minimum:

ansible-playbook ansible/site.yml --syntax-check

Preferred for role, template, or vars changes:

ansible-playbook ansible/site.yml --limit <host> --check --diff

Agent workflow expectations

• Read the relevant inventory, vars, role tasks, templates, and deployed dotfiles before editing.
• Do not change unrelated files to "clean things up".
• Keep README.md and AGENTS.md aligned when workflows materially change.
• If you add a new operational area, also add the validation command agents should run.
• Prefer host-limited validation before broad apply.
• Call out any verification you could not run.