fix(agent): Explore and claude-code-guide no longer hard-code model=haiku

CHANGELOG.md

@@ -26,6 +26,8 @@ The format is based on Keep a Changelog, and this project currently tracks chang
 
 - `todo_write` tool now updates an existing unchecked item in-place when `checked=True` instead of appending a duplicate `[x]` line.
 
+- Built-in `Explore` and `claude-code-guide` agents no longer hard-code `model="haiku"`, which caused them to fail for users on non-Anthropic providers (OpenAI, Bedrock, custom base URLs, etc.). Both agents now use `model="inherit"` so they run with whatever model the parent session is using. `build_inherited_cli_flags` is also fixed to skip the `--model` flag entirely when the value is `"inherit"`, letting the subprocess correctly inherit the parent model via the `OPENHARNESS_MODEL` environment variable instead of receiving the literal string `"inherit"` as a model name.
+
 - React TUI spinner now stays visible throughout the entire agent turn: `assistant_complete` no longer resets `busy` state prematurely, and `tool_started` explicitly sets `busy=true` so the status bar remains active even when tool calls follow an assistant message. `line_complete` is the sole signal that ends the turn and clears the spinner.
 - Skill loader now uses `yaml.safe_load` to parse SKILL.md frontmatter, correctly handling YAML block scalars (`>`, `|`), quoted values, and other standard YAML constructs instead of naive line-by-line splitting.
 - `BackendHostConfig` was missing the `cwd` field, causing `AttributeError: 'BackendHostConfig' object has no attribute 'cwd'` on startup when `oh` was run after the runtime refactor that added `cwd` support to `build_runtime`.

src/openharness/coordinator/agent_definitions.py

@@ -546,7 +546,7 @@ class AgentDefinition(BaseModel):
         ),
         tools=["Glob", "Grep", "Read", "WebFetch", "WebSearch"],
         system_prompt=_CLAUDE_CODE_GUIDE_SYSTEM_PROMPT,
-        model="haiku",
+        model="inherit",
         permission_mode="dontAsk",
         subagent_type="claude-code-guide",
         source="builtin",
@@ -565,7 +565,7 @@ class AgentDefinition(BaseModel):
         ),
         disallowed_tools=["agent", "exit_plan_mode", "file_edit", "file_write", "notebook_edit"],
         system_prompt=_EXPLORE_SYSTEM_PROMPT,
-        model="haiku",
+        model="inherit",
         omit_claude_md=True,
         subagent_type="Explore",
         source="builtin",

src/openharness/swarm/spawn_utils.py

@@ -142,7 +142,8 @@ def build_inherited_cli_flags(
             flags.extend(["--permission-mode", "acceptEdits"])
 
     # --- Model override ----------------------------------------------------
-    if model:
+    # "inherit" means use the parent's model via the OPENHARNESS_MODEL env var.
+    if model and model != "inherit":
         flags.extend(["--model", shlex.quote(model)])
 
     # --- Settings path propagation ----------------------------------------

tests/test_coordinator/test_agent_definitions.py

@@ -83,6 +83,43 @@ def test_builtin_general_purpose_has_all_tools():
 
 
 # ---------------------------------------------------------------------------
+# Model inheritance: provider-agnostic built-in agents
+# ---------------------------------------------------------------------------
+
+_PROVIDER_SPECIFIC_MODELS = {"haiku", "sonnet", "opus"}
+"""Short model aliases that only exist for Anthropic's API."""
+
+
+def test_builtin_explore_does_not_hardcode_provider_model():
+    """Explore must use 'inherit' (or None) so it works with any API provider."""
+    builtins = get_builtin_agent_definitions()
+    explore = next(a for a in builtins if a.name == "Explore")
+    assert explore.model not in _PROVIDER_SPECIFIC_MODELS, (
+        f"Explore.model={explore.model!r} hard-codes a provider-specific model alias; "
+        "use 'inherit' so the agent works with non-Anthropic providers."
+    )
+
+
+def test_builtin_claude_code_guide_does_not_hardcode_provider_model():
+    """claude-code-guide must not hard-code an Anthropic-only model alias."""
+    builtins = get_builtin_agent_definitions()
+    guide = next(a for a in builtins if a.name == "claude-code-guide")
+    assert guide.model not in _PROVIDER_SPECIFIC_MODELS, (
+        f"claude-code-guide.model={guide.model!r} hard-codes a provider-specific model alias; "
+        "use 'inherit' so the agent works with non-Anthropic providers."
+    )
+
+
+def test_builtin_provider_agnostic_agents_use_inherit_or_none():
+    """Plan, verification, Explore, and claude-code-guide must not override the model."""
+    agnostic_agents = {"Plan", "verification", "Explore", "claude-code-guide"}
+    builtins = {a.name: a for a in get_builtin_agent_definitions()}
+    for name in agnostic_agents:
+        agent = builtins[name]
+        assert agent.model in {None, "inherit"}, (
+            f"Built-in agent {name!r} sets model={agent.model!r}; "
+            "provider-agnostic agents should use None or 'inherit'."
+        )
 # _parse_agent_frontmatter
 # ---------------------------------------------------------------------------
 

tests/test_swarm/test_spawn_utils.py

@@ -6,6 +6,7 @@
 
 from openharness.swarm.spawn_utils import (
     TEAMMATE_COMMAND_ENV_VAR,
+    build_inherited_cli_flags,
     build_inherited_env_vars,
     get_teammate_command,
 )
@@ -26,3 +27,32 @@ def test_build_inherited_env_vars_disables_coordinator_mode(monkeypatch):
     env = build_inherited_env_vars()
 
     assert env["CLAUDE_CODE_COORDINATOR_MODE"] == "0"
+
+
+# ---------------------------------------------------------------------------
+# build_inherited_cli_flags – model handling
+# ---------------------------------------------------------------------------
+
+
+def test_build_inherited_cli_flags_explicit_model_included():
+    flags = build_inherited_cli_flags(model="claude-opus-4-5")
+    assert "--model" in flags
+    idx = flags.index("--model")
+    assert "claude-opus-4-5" in flags[idx + 1]
+
+
+def test_build_inherited_cli_flags_inherit_model_excluded():
+    """model='inherit' must NOT produce a --model flag so the subprocess
+    picks up the parent's model from the OPENHARNESS_MODEL env var."""
+    flags = build_inherited_cli_flags(model="inherit")
+    assert "--model" not in flags
+
+
+def test_build_inherited_cli_flags_none_model_excluded():
+    flags = build_inherited_cli_flags(model=None)
+    assert "--model" not in flags
+
+
+def test_build_inherited_cli_flags_empty_string_model_excluded():
+    flags = build_inherited_cli_flags(model="")
+    assert "--model" not in flags