feat(cli): /init — generate or update AGENTS.md from a project scan

Cross-surface slash command (CLI, gateway, TUI) following the /learn prompt-injection pattern. Port of Codex /init.

tests/hermes_cli/test_init_command.py

@@ -0,0 +1,117 @@
+"""Tests for /init — generate or update AGENTS.md from a project scan.
+
+Covers the shared prompt builder (hermes_cli.init_command.build_init_prompt)
+and the slash-command registry wiring. /init has no engine and no model tool:
+it builds a guidance-laden prompt that the live agent runs as a normal turn
+(the /learn pattern), so these are the load-bearing behavior contracts.
+"""
+
+from hermes_cli.init_command import (
+    _QUALITY_BAR,
+    build_init_prompt,
+    build_init_prompt_for_cwd,
+)
+
+
+class TestBuildInitPrompt:
+    def test_includes_the_cwd(self):
+        prompt = build_init_prompt("/home/alice/projects/acme")
+        assert "/home/alice/projects/acme" in prompt
+
+    def test_mentions_agents_md(self):
+        prompt = build_init_prompt("/tmp/proj")
+        assert "AGENTS.md" in prompt
+
+    def test_fresh_generation_when_no_existing_file(self):
+        prompt = build_init_prompt("/tmp/proj", existing_file=None)
+        assert "generate an AGENTS.md" in prompt
+        # No merge discipline block for a fresh file.
+        assert "MERGE DISCIPLINE" not in prompt
+
+    def test_merge_not_overwrite_when_existing_file_passed(self):
+        existing = "# My Project\n\nAlways run `make lint` before committing.\n"
+        prompt = build_init_prompt("/tmp/proj", existing_file=existing)
+        low = prompt.lower()
+        # Update mode, with explicit merge-not-overwrite discipline.
+        assert "UPDATE the existing AGENTS.md" in prompt
+        assert "merge" in low
+        assert "do not overwrite" in low or "not overwrite" in low
+        assert "preserve" in low
+        # And it carries the current content so the agent can merge.
+        assert existing.strip() in prompt
+
+    def test_empty_existing_file_still_triggers_update_mode(self):
+        # An existing-but-empty AGENTS.md is still an update, not a fresh gen
+        # (None means "no file"; "" means "empty file").
+        prompt = build_init_prompt("/tmp/proj", existing_file="")
+        assert "UPDATE the existing AGENTS.md" in prompt
+
+    def test_includes_extra_notes_verbatim(self):
+        notes = "focus on the test setup, and mention the flaky e2e suite"
+        prompt = build_init_prompt("/tmp/proj", extra=notes)
+        assert notes in prompt
+
+    def test_no_notes_section_when_extra_empty(self):
+        assert "USER NOTES" not in build_init_prompt("/tmp/proj", extra="  ")
+        assert "USER NOTES" in build_init_prompt("/tmp/proj", extra="hi")
+
+    def test_always_includes_the_quality_bar(self):
+        for existing in (None, "# old content"):
+            prompt = build_init_prompt("/tmp/proj", existing_file=existing)
+            assert _QUALITY_BAR in prompt
+
+    def test_quality_bar_demands_exact_commands_and_conciseness(self):
+        low = _QUALITY_BAR.lower()
+        assert "100 lines" in low
+        assert "never invent" in low
+        assert "no generic advice" in low
+
+    def test_references_read_only_scan_tools(self):
+        prompt = build_init_prompt("/tmp/proj")
+        for tool in ("read_file", "search_files", "write_file"):
+            assert tool in prompt
+
+
+class TestBuildInitPromptForCwd:
+    def test_defaults_to_process_cwd(self, tmp_path, monkeypatch):
+        monkeypatch.chdir(tmp_path)
+        prompt = build_init_prompt_for_cwd()
+        assert str(tmp_path) in prompt
+        assert "generate an AGENTS.md" in prompt
+
+    def test_reads_existing_agents_md(self, tmp_path):
+        (tmp_path / "AGENTS.md").write_text(
+            "# Existing\n\nRun `tox -e py311`.\n", encoding="utf-8"
+        )
+        prompt = build_init_prompt_for_cwd(cwd=str(tmp_path))
+        assert "UPDATE the existing AGENTS.md" in prompt
+        assert "Run `tox -e py311`." in prompt
+
+    def test_passes_extra_through(self, tmp_path):
+        prompt = build_init_prompt_for_cwd(cwd=str(tmp_path), extra="keep it short")
+        assert "keep it short" in prompt
+
+
+class TestInitRegistryWiring:
+    def test_init_is_registered_and_resolves(self):
+        from hermes_cli.commands import resolve_command
+
+        cmd = resolve_command("init")
+        assert cmd is not None
+        assert cmd.name == "init"
+
+    def test_init_is_in_tools_and_skills_category(self):
+        from hermes_cli.commands import resolve_command
+
+        assert resolve_command("init").category == "Tools & Skills"
+
+    def test_init_works_on_the_gateway(self):
+        # /init is a both-surfaces command like /learn, not CLI-only.
+        from hermes_cli.commands import GATEWAY_KNOWN_COMMANDS
+
+        assert "init" in GATEWAY_KNOWN_COMMANDS
+
+    def test_init_is_not_cli_only(self):
+        from hermes_cli.commands import resolve_command
+
+        assert not resolve_command("init").cli_only