diff --git a/src/specify_cli/agents.py b/src/specify_cli/agents.py
index 726b0fd2a6..244c2ad075 100644
--- a/src/specify_cli/agents.py
+++ b/src/specify_cli/agents.py
@@ -453,7 +453,9 @@ def register_commands(
             raise ValueError(f"Unsupported agent: {agent_name}")
 
         agent_config = self.AGENT_CONFIGS[agent_name]
-        commands_dir = project_root / agent_config["dir"]
+        commands_dir = self._resolve_agent_dir(
+            agent_name, agent_config, project_root,
+        )
         commands_dir.mkdir(parents=True, exist_ok=True)
 
         registered = []
@@ -609,6 +611,40 @@ def write_copilot_prompt(project_root: Path, cmd_name: str) -> None:
         CommandRegistrar._ensure_inside(prompt_file, prompts_dir)
         prompt_file.write_text(f"---\nagent: {cmd_name}\n---\n", encoding="utf-8")
 
+    @staticmethod
+    def _resolve_agent_dir(
+        agent_name: str,
+        agent_config: dict[str, Any],
+        project_root: Path,
+    ) -> Path:
+        """Return the agent command directory, falling back to legacy_dir.
+
+        When the canonical directory (``agent_config["dir"]``) does not
+        exist but a ``legacy_dir`` is configured and present on disk,
+        returns the legacy path and emits a deprecation warning advising
+        the user to upgrade.
+
+        Integrations that do not declare ``legacy_dir`` get the canonical
+        path unconditionally — no fallback, no warning.
+        """
+        agent_dir = project_root / agent_config["dir"]
+        if not agent_dir.exists():
+            legacy = agent_config.get("legacy_dir")
+            if legacy:
+                legacy_dir = project_root / legacy
+                if legacy_dir.exists():
+                    import warnings
+
+                    warnings.warn(
+                        f"Found legacy {legacy}/ directory for "
+                        f"{agent_name}. Run 'specify integration "
+                        f"upgrade {agent_name}' to migrate to "
+                        f"{agent_config['dir']}/.",
+                        stacklevel=3,
+                    )
+                    return legacy_dir
+        return agent_dir
+
     def register_commands_for_all_agents(
         self,
         commands: List[Dict[str, Any]],
@@ -633,7 +669,9 @@ def register_commands_for_all_agents(
 
         self._ensure_configs()
         for agent_name, agent_config in self.AGENT_CONFIGS.items():
-            agent_dir = project_root / agent_config["dir"]
+            agent_dir = self._resolve_agent_dir(
+                agent_name, agent_config, project_root,
+            )
 
             if agent_dir.exists():
                 try:
@@ -681,7 +719,9 @@ def register_commands_for_non_skill_agents(
         for agent_name, agent_config in self.AGENT_CONFIGS.items():
             if agent_config.get("extension") == "/SKILL.md":
                 continue
-            agent_dir = project_root / agent_config["dir"]
+            agent_dir = self._resolve_agent_dir(
+                agent_name, agent_config, project_root,
+            )
             if agent_dir.exists():
                 try:
                     registered = self.register_commands(
@@ -710,7 +750,9 @@ def unregister_commands(
                 continue
 
             agent_config = self.AGENT_CONFIGS[agent_name]
-            commands_dir = project_root / agent_config["dir"]
+            commands_dir = self._resolve_agent_dir(
+                agent_name, agent_config, project_root,
+            )
 
             for cmd_name in cmd_names:
                 output_name = self._compute_output_name(
diff --git a/src/specify_cli/integrations/opencode/__init__.py b/src/specify_cli/integrations/opencode/__init__.py
index 17db2bd11b..4fa9c724ac 100644
--- a/src/specify_cli/integrations/opencode/__init__.py
+++ b/src/specify_cli/integrations/opencode/__init__.py
@@ -8,12 +8,13 @@ class OpencodeIntegration(MarkdownIntegration):
     config = {
         "name": "opencode",
         "folder": ".opencode/",
-        "commands_subdir": "command",
+        "commands_subdir": "commands",
         "install_url": "https://opencode.ai",
         "requires_cli": True,
     }
     registrar_config = {
-        "dir": ".opencode/command",
+        "dir": ".opencode/commands",
+        "legacy_dir": ".opencode/command",
         "format": "markdown",
         "args": "$ARGUMENTS",
         "extension": ".md",
diff --git a/tests/integrations/test_integration_opencode.py b/tests/integrations/test_integration_opencode.py
index 427fd15167..39cf5ee9f5 100644
--- a/tests/integrations/test_integration_opencode.py
+++ b/tests/integrations/test_integration_opencode.py
@@ -1,6 +1,10 @@
 """Tests for OpencodeIntegration."""
 
+import warnings
+
+from specify_cli.agents import CommandRegistrar
 from specify_cli.integrations import get_integration
+from specify_cli.integrations.manifest import IntegrationManifest
 
 from .test_integration_base_markdown import MarkdownIntegrationTests
 
@@ -8,8 +12,8 @@
 class TestOpencodeIntegration(MarkdownIntegrationTests):
     KEY = "opencode"
     FOLDER = ".opencode/"
-    COMMANDS_SUBDIR = "command"
-    REGISTRAR_DIR = ".opencode/command"
+    COMMANDS_SUBDIR = "commands"
+    REGISTRAR_DIR = ".opencode/commands"
     CONTEXT_FILE = "AGENTS.md"
 
     def test_build_exec_args_uses_run_command_dispatch(self):
@@ -57,3 +61,107 @@ def test_build_exec_args_keeps_plain_prompt_dispatch(self):
         args = integration.build_exec_args("explain this repository", output_json=False)
 
         assert args == ["opencode", "run", "explain this repository"]
+
+    def test_registrar_config_has_legacy_dir(self):
+        integration = get_integration(self.KEY)
+        assert integration.registrar_config["legacy_dir"] == ".opencode/command"
+
+    def test_legacy_dir_extension_registration(self, tmp_path):
+        """Extensions register in legacy .opencode/command/ with a warning."""
+        # Seed a legacy project with only .opencode/command/
+        legacy_dir = tmp_path / ".opencode" / "command"
+        legacy_dir.mkdir(parents=True)
+        (legacy_dir / "speckit.specify.md").write_text("# existing", encoding="utf-8")
+
+        # Create a source command file for the registrar
+        src_dir = tmp_path / "_ext_src"
+        src_dir.mkdir()
+        (src_dir / "myext.md").write_text(
+            "---\ndescription: test\n---\n# ext command", encoding="utf-8",
+        )
+
+        registrar = CommandRegistrar()
+        commands = [{"name": "speckit.myext", "file": "myext.md"}]
+
+        with warnings.catch_warnings(record=True) as caught:
+            warnings.simplefilter("always")
+            results = registrar.register_commands_for_all_agents(
+                commands, "test-ext", src_dir, tmp_path,
+            )
+
+        # Should have registered in the legacy directory
+        assert "opencode" in results
+        assert (legacy_dir / "speckit.myext.md").exists()
+        # Canonical directory should NOT have been created
+        assert not (tmp_path / ".opencode" / "commands").exists()
+        # Should have emitted a deprecation warning
+        opencode_warnings = [
+            w for w in caught
+            if "legacy" in str(w.message) and "opencode" in str(w.message)
+        ]
+        assert len(opencode_warnings) >= 1
+        assert "specify integration upgrade" in str(opencode_warnings[0].message)
+
+    def test_legacy_dir_unregister(self, tmp_path):
+        """Unregister finds commands in legacy .opencode/command/ dir."""
+        legacy_dir = tmp_path / ".opencode" / "command"
+        legacy_dir.mkdir(parents=True)
+        cmd_file = legacy_dir / "speckit.myext.md"
+        cmd_file.write_text("# ext command", encoding="utf-8")
+
+        registrar = CommandRegistrar()
+
+        with warnings.catch_warnings(record=True):
+            warnings.simplefilter("always")
+            registrar.unregister_commands(
+                {"opencode": ["speckit.myext"]}, tmp_path,
+            )
+
+        assert not cmd_file.exists()
+
+    def test_canonical_dir_preferred_over_legacy(self, tmp_path):
+        """When both dirs exist, canonical .opencode/commands/ is used."""
+        legacy_dir = tmp_path / ".opencode" / "command"
+        legacy_dir.mkdir(parents=True)
+        canonical_dir = tmp_path / ".opencode" / "commands"
+        canonical_dir.mkdir(parents=True)
+        (canonical_dir / "speckit.specify.md").write_text("# cmd", encoding="utf-8")
+
+        # Create a source command file for the registrar
+        src_dir = tmp_path / "_ext_src"
+        src_dir.mkdir()
+        (src_dir / "myext.md").write_text(
+            "---\ndescription: test\n---\n# ext command", encoding="utf-8",
+        )
+
+        registrar = CommandRegistrar()
+        commands = [{"name": "speckit.myext", "file": "myext.md"}]
+
+        with warnings.catch_warnings(record=True) as caught:
+            warnings.simplefilter("always")
+            results = registrar.register_commands_for_all_agents(
+                commands, "test-ext", src_dir, tmp_path,
+            )
+
+        # Should register in canonical dir, not legacy
+        assert "opencode" in results
+        assert (canonical_dir / "speckit.myext.md").exists()
+        assert not (legacy_dir / "speckit.myext.md").exists()
+        # No legacy warning when canonical dir exists
+        opencode_warnings = [
+            w for w in caught
+            if "legacy" in str(w.message) and "opencode" in str(w.message)
+        ]
+        assert len(opencode_warnings) == 0
+
+    def test_setup_writes_to_canonical_dir(self, tmp_path):
+        """New installs always write to .opencode/commands/ (plural)."""
+        integration = get_integration(self.KEY)
+        manifest = IntegrationManifest(self.KEY, tmp_path)
+        integration.setup(tmp_path, manifest)
+
+        canonical = tmp_path / ".opencode" / "commands"
+        legacy = tmp_path / ".opencode" / "command"
+        assert canonical.is_dir()
+        assert not legacy.exists()
+        assert any(canonical.glob("speckit.*.md"))
diff --git a/tests/integrations/test_integration_subcommand.py b/tests/integrations/test_integration_subcommand.py
index 750bbb6efa..c15d2d6a64 100644
--- a/tests/integrations/test_integration_subcommand.py
+++ b/tests/integrations/test_integration_subcommand.py
@@ -762,7 +762,7 @@ def test_switch_migrates_extension_commands(self, tmp_path):
         assert result.exit_code == 0, result.output
 
         # Git extension commands should exist for opencode
-        opencode_git_feature = project / ".opencode" / "command" / "speckit.git.feature.md"
+        opencode_git_feature = project / ".opencode" / "commands" / "speckit.git.feature.md"
         assert opencode_git_feature.exists(), "Git extension command should exist for opencode"
 
         # Old kimi extension skills should be removed
@@ -837,7 +837,7 @@ def test_switch_migrates_copilot_skills_extension_commands(self, tmp_path):
         ])
         assert result.exit_code == 0, result.output
 
-        opencode_git_feature = project / ".opencode" / "command" / "speckit.git.feature.md"
+        opencode_git_feature = project / ".opencode" / "commands" / "speckit.git.feature.md"
         assert opencode_git_feature.exists(), "Git extension command should exist for opencode"
         assert not copilot_git_feature.exists(), "Old Copilot extension skill should be removed"
 
@@ -858,7 +858,7 @@ def test_switch_does_not_register_disabled_extensions(self, tmp_path):
         result = _run_in_project(project, ["extension", "disable", "git"])
         assert result.exit_code == 0, result.output
 
-        opencode_git_feature = project / ".opencode" / "command" / "speckit.git.feature.md"
+        opencode_git_feature = project / ".opencode" / "commands" / "speckit.git.feature.md"
         assert opencode_git_feature.exists(), "Disabled extension command remains until integration switch"
 
         result = _run_in_project(project, [
@@ -1022,6 +1022,49 @@ def test_upgrade_non_default_keeps_default_template_invocations(self, tmp_path):
         assert data["integration"] == "gemini"
         assert "/speckit.plan" in template.read_text(encoding="utf-8")
 
+    def test_upgrade_migrates_opencode_legacy_dir(self, tmp_path):
+        """Upgrade moves OpenCode commands from .opencode/command/ to .opencode/commands/."""
+        project = _init_project(tmp_path, "opencode")
+
+        # Simulate a legacy project: rename commands/ back to command/
+        canonical = project / ".opencode" / "commands"
+        legacy = project / ".opencode" / "command"
+        assert canonical.is_dir(), "init should have created .opencode/commands/"
+        canonical.rename(legacy)
+        assert legacy.is_dir()
+        assert not canonical.exists()
+
+        # Patch the manifest to reflect old paths (command/ not commands/)
+        manifest_path = project / ".specify" / "integrations" / "opencode.manifest.json"
+        manifest_data = json.loads(manifest_path.read_text(encoding="utf-8"))
+        patched_files = {}
+        for path, info in manifest_data.get("files", {}).items():
+            patched_files[path.replace(".opencode/commands/", ".opencode/command/")] = info
+        manifest_data["files"] = patched_files
+        manifest_path.write_text(json.dumps(manifest_data), encoding="utf-8")
+
+        old_commands = sorted(legacy.glob("speckit.*.md"))
+        assert len(old_commands) > 0, "Legacy dir should have speckit command files"
+
+        result = _run_in_project(project, [
+            "integration", "upgrade", "opencode",
+            "--script", "sh",
+            "--force",
+        ])
+        assert result.exit_code == 0, f"upgrade failed: {result.output}"
+
+        # New commands in canonical dir
+        assert canonical.is_dir(), ".opencode/commands/ should exist after upgrade"
+        new_commands = sorted(canonical.glob("speckit.*.md"))
+        assert len(new_commands) > 0, "Commands should exist in .opencode/commands/"
+
+        # Stale files removed from legacy dir
+        remaining = list(legacy.glob("speckit.*.md"))
+        assert len(remaining) == 0, (
+            f"Legacy .opencode/command/ should have no speckit files after upgrade, "
+            f"found: {[f.name for f in remaining]}"
+        )
+
 
 # ── Full lifecycle ───────────────────────────────────────────────────