fix(agent): make parallel_tool_calls configurable to fix Amazon Bedrock query/chat (#175)

config.yaml.example

@@ -2,6 +2,16 @@ model: gpt-5.4                   # LLM model (any LiteLLM-supported provider)
 language: en                     # Wiki output language
 pageindex_threshold: 20          # PDF pages threshold for PageIndex
 
+# Optional: whether the LLM agents (query, chat, lint, skill) may call tools
+# in parallel. Leave it UNSET (commented out) to keep OpenKB's per-agent
+# defaults. Setting it applies the SAME value to every agent:
+#   true    allow parallel tool calls
+#   false   force sequential tool calls
+#   null    don't send the setting at all (use the provider default) — REQUIRED
+#           for Amazon Bedrock Claude, which rejects the request when
+#           parallel_tool_calls is sent at all (any value). See #175.
+# parallel_tool_calls: null
+
 # Optional: override the entity-type vocabulary used for entity pages.
 # Omit this key to use the default 7 types
 # (person, organization, place, product, work, event, other).

examples/configuration/README.md

@@ -70,6 +70,16 @@ model: gpt-5.4                   # LLM model (any LiteLLM-supported provider)
 language: en                     # Wiki output language
 pageindex_threshold: 20          # PDF pages threshold for PageIndex
 
+# Optional: whether the LLM agents (query, chat, lint, skill) may call tools
+# in parallel. Leave it UNSET (commented out) to keep OpenKB's per-agent
+# defaults. Setting it applies the SAME value to every agent:
+#   true    allow parallel tool calls
+#   false   force sequential tool calls
+#   null    don't send the setting at all (use the provider default) — REQUIRED
+#           for Amazon Bedrock Claude, which rejects the request when
+#           parallel_tool_calls is sent at all (any value). See #175.
+# parallel_tool_calls: null
+
 # Optional: override the entity-type vocabulary used for entity pages.
 # Omit this key to use the default 7 types
 # (person, organization, place, product, work, event, other).
@@ -95,6 +105,7 @@ pageindex_threshold: 20          # PDF pages threshold for PageIndex
 | `model` | `gpt-5.4` | LLM used for all compile/query/chat work. |
 | `language` | `en` | Language the wiki is written in. |
 | `pageindex_threshold` | `20` | PDFs with this many pages **or more** take the long-doc (PageIndex) path; shorter ones go through the short-doc path. See [`pageindex-cloud/`](../pageindex-cloud/). |
+| `parallel_tool_calls` | unset | Whether the LLM agents (query, chat, lint, skill) may call tools in parallel. Unset keeps OpenKB's per-agent defaults; `true`/`false` force allow/sequential for every agent; `null` omits the setting (provider default). **Amazon Bedrock needs `null`** (see below). |
 | `entity_types` | 7 defaults | Custom vocabulary for entity pages. `other` is always kept. |
 | `litellm:` | – | A pass-through block for LiteLLM. See below. |
 
@@ -177,6 +188,26 @@ LLM_API_KEY=your-key-here
   won't warn about a missing one.
 - **PageIndex Cloud** uses a separate `PAGEINDEX_API_KEY` (see
   [`pageindex-cloud/`](../pageindex-cloud/)).
+- **Amazon Bedrock** (`model: bedrock/...`) authenticates with AWS credentials,
+  not `LLM_API_KEY`. Put them in `<kb>/.env` (LiteLLM/boto3 read them from the
+  environment); `LLM_API_KEY` isn't needed:
+
+  ```bash
+  # <kb>/.env
+  AWS_ACCESS_KEY_ID=...
+  AWS_SECRET_ACCESS_KEY=...
+  AWS_REGION_NAME=eu-central-1
+  ```
+
+  ```yaml
+  # <kb>/.openkb/config.yaml
+  model: bedrock/eu.anthropic.claude-sonnet-4-6
+  parallel_tool_calls: null   # REQUIRED for Bedrock Claude: sending
+                              # parallel_tool_calls at all (any value) makes
+                              # LiteLLM send a malformed tool_choice that Bedrock
+                              # rejects (#175). null tells OpenKB to omit it.
+                              # Write it as bare `null` — not `None` or "null".
+  ```
 
 **Where keys are read from** (first match wins, existing env always respected):
 

openkb/agent/linter.py

@@ -8,7 +8,7 @@
 from agents.model_settings import ModelSettings
 
 from openkb.agent.tools import list_wiki_files, read_wiki_file
-from openkb.config import get_extra_headers, get_timeout_extra_args
+from openkb.config import resolve_model_settings
 from openkb.schema import get_agents_md
 
 MAX_TURNS = 50
@@ -82,10 +82,7 @@ def read_file(path: str) -> str:
         instructions=instructions,
         tools=[list_files, read_file],
         model=f"litellm/{model}",
-        model_settings=ModelSettings(
-            extra_headers=get_extra_headers() or None,
-            extra_args=get_timeout_extra_args(),
-        ),
+        model_settings=ModelSettings(**resolve_model_settings(default_parallel_tool_calls=None)),
     )
 
 

openkb/agent/query.py

@@ -12,7 +12,7 @@
     read_wiki_image,
     write_kb_file,
 )
-from openkb.config import get_extra_headers, get_timeout_extra_args
+from openkb.config import resolve_model_settings
 from openkb.schema import get_agents_md
 
 MAX_TURNS = 50
@@ -95,11 +95,7 @@ def get_image(image_path: str) -> ToolOutputImage | ToolOutputText:
         instructions=instructions,
         tools=[read_file, get_page_content, get_image],
         model=f"litellm/{model}",
-        model_settings=ModelSettings(
-            parallel_tool_calls=False,
-            extra_headers=get_extra_headers() or None,
-            extra_args=get_timeout_extra_args(),
-        ),
+        model_settings=ModelSettings(**resolve_model_settings()),
     )
 
 

openkb/cli.py

@@ -56,6 +56,8 @@ def filter(self, record: logging.LogRecord) -> bool:
     register_kb,
     resolve_extra_headers,
     set_extra_headers,
+    resolve_parallel_tool_calls,
+    set_parallel_tool_calls,
     resolve_timeout,
     set_timeout,
     resolve_litellm_settings,
@@ -174,6 +176,8 @@ def _setup_llm_key(kb_dir: Path | None = None) -> None:
     provider: str | None = None
     extra_headers: dict[str, str] = {}
     timeout: float | None = None
+    parallel_tool_calls: bool | None = None
+    parallel_tool_calls_explicit = False
     litellm_settings: dict = {}
     if kb_dir is not None:
         config_path = kb_dir / ".openkb" / "config.yaml"
@@ -183,6 +187,7 @@ def _setup_llm_key(kb_dir: Path | None = None) -> None:
             provider = _extract_provider(str(model))
             extra_headers = resolve_extra_headers(config)
             timeout = resolve_timeout(config)
+            parallel_tool_calls, parallel_tool_calls_explicit = resolve_parallel_tool_calls(config)
             litellm_settings = resolve_litellm_settings(config)
             # `timeout` / `extra_headers` in the block route to the per-call
             # stashes (replacing the legacy top-level keys); the rest are globals.
@@ -194,6 +199,7 @@ def _setup_llm_key(kb_dir: Path | None = None) -> None:
                 timeout = resolve_timeout({"timeout": litellm_settings.pop("timeout")})
     set_extra_headers(extra_headers)
     set_timeout(timeout)
+    set_parallel_tool_calls(parallel_tool_calls, parallel_tool_calls_explicit)
     _apply_litellm_settings(litellm_settings)
 
     if not api_key:

openkb/config.py

@@ -144,6 +144,30 @@ def resolve_extra_headers(config: dict) -> dict[str, str]:
     return headers
 
 
+def resolve_parallel_tool_calls(config: dict) -> tuple[bool | None, bool]:
+    """Resolve the optional ``parallel_tool_calls:`` key to ``(value, was_explicit)``.
+
+    Absent → ``(None, False)`` so each agent applies its own default (see
+    ``resolve_model_settings``). ``true``/``false`` → that bool; explicit
+    ``null`` → ``None`` (omit — the Amazon Bedrock #175 escape hatch); both with
+    ``was_explicit=True`` so they override every agent uniformly. An invalid
+    value degrades to omit (never breaks a provider), with a warning.
+    """
+    if "parallel_tool_calls" not in config:
+        return None, False
+    value = config["parallel_tool_calls"]
+    if value is None:
+        return None, True
+    if isinstance(value, bool):
+        return value, True
+    logger.warning(
+        "config: 'parallel_tool_calls' must be true, false, or null, got %r "
+        "— omitting the setting.",
+        value,
+    )
+    return None, True
+
+
 def resolve_timeout(config: dict) -> float | None:
     """Resolve the optional ``timeout:`` key to a finite positive number of seconds.
 
@@ -243,6 +267,42 @@ def get_timeout_extra_args() -> dict[str, float] | None:
     return {"timeout": _runtime_timeout} if _runtime_timeout is not None else None
 
 
+# Process-wide agent ``parallel_tool_calls`` as ``(value, was_explicit)``, set
+# from config by the CLI and read when building agents. ``(None, False)`` = not
+# configured, so each agent falls back to its own default (resolve_model_settings).
+_runtime_parallel_tool_calls: tuple[bool | None, bool] = (None, False)
+
+
+def set_parallel_tool_calls(value: bool | None, was_explicit: bool) -> None:
+    """Set the process-wide ``parallel_tool_calls`` — see :func:`resolve_parallel_tool_calls`."""
+    global _runtime_parallel_tool_calls
+    _runtime_parallel_tool_calls = (value, was_explicit)
+
+
+def get_parallel_tool_calls() -> tuple[bool | None, bool]:
+    """Return the process-wide ``parallel_tool_calls`` as ``(value, was_explicit)``."""
+    return _runtime_parallel_tool_calls
+
+
+def resolve_model_settings(*, default_parallel_tool_calls: bool | None = False) -> dict[str, Any]:
+    """Assemble the agents-SDK ``ModelSettings`` kwargs from the process-wide LLM
+    runtime settings — the single place tool-using agent builders wire them in.
+
+    ``default_parallel_tool_calls`` (the caller's own historical default) is used
+    only when config didn't set ``parallel_tool_calls``; an explicit value always
+    wins. Tool-less agents (skill-eval graders) skip this and omit the setting —
+    the SDK forwards an explicit ``False`` even without tools, which strict
+    OpenAI-compatible endpoints reject.
+    """
+    value, was_explicit = get_parallel_tool_calls()
+    parallel_tool_calls = value if was_explicit else default_parallel_tool_calls
+    return {
+        "extra_headers": get_extra_headers() or None,
+        "extra_args": get_timeout_extra_args(),
+        "parallel_tool_calls": parallel_tool_calls,
+    }
+
+
 def load_config(config_path: Path) -> dict[str, Any]:
     """Load YAML config from config_path, merged with DEFAULT_CONFIG.
 

openkb/skill/creator.py

@@ -20,7 +20,7 @@
 from agents import Agent, Runner, ToolOutputImage, ToolOutputText, function_tool
 from agents.model_settings import ModelSettings
 
-from openkb.config import get_extra_headers, get_timeout_extra_args
+from openkb.config import resolve_model_settings
 from openkb.prompts import load_prompt
 from openkb.schema import get_agents_md
 from openkb.skill import skill_dir
@@ -154,18 +154,14 @@ def done(summary: str) -> str:
             done,
         ],
         model=f"litellm/{model}",
-        # Allow the model to issue multiple read tool calls in one turn —
-        # the compile's early phase is a fan-out (list dir -> read N
-        # summaries -> read N source page-ranges), and serialising each
-        # read into its own turn costs roughly 5-10 extra round-trips per
-        # compile. Writes serialise naturally because each
-        # `write_skill_file` depends on accumulated reads; the model has
-        # no reason to issue parallel writes to the same path.
-        model_settings=ModelSettings(
-            parallel_tool_calls=True,
-            extra_headers=get_extra_headers() or None,
-            extra_args=get_timeout_extra_args(),
-        ),
+        # Default to allowing parallel read tool calls — the compile's early
+        # phase is a fan-out (list dir -> read N summaries -> read N source
+        # page-ranges), and serialising each read into its own turn costs
+        # roughly 5-10 extra round-trips per compile. Writes serialise
+        # naturally because each `write_skill_file` depends on accumulated
+        # reads; the model has no reason to issue parallel writes to the
+        # same path. An explicit config value (e.g. `null` for Bedrock) wins.
+        model_settings=ModelSettings(**resolve_model_settings(default_parallel_tool_calls=True)),
     )
 
 

tests/conftest.py

@@ -5,12 +5,14 @@
 
 @pytest.fixture(autouse=True)
 def _reset_extra_headers():
-    """Keep the process-wide LLM extra-headers / timeout stashes from leaking across tests."""
-    from openkb.config import set_extra_headers, set_timeout
+    """Keep the process-wide LLM extra-headers / timeout / parallel-tool-calls
+    stashes from leaking across tests."""
+    from openkb.config import set_extra_headers, set_parallel_tool_calls, set_timeout
 
     yield
     set_extra_headers({})
     set_timeout(None)
+    set_parallel_tool_calls(None, False)
 
 
 @pytest.fixture

tests/test_config.py

@@ -3,16 +3,125 @@
 from openkb.config import (
     DEFAULT_CONFIG,
     get_extra_headers,
+    get_parallel_tool_calls,
     get_timeout,
     load_config,
     resolve_extra_headers,
     resolve_litellm_settings,
+    resolve_model_settings,
+    resolve_parallel_tool_calls,
     resolve_timeout,
     save_config,
     set_extra_headers,
+    set_parallel_tool_calls,
     set_timeout,
 )
 
+# --- parallel_tool_calls ------------------------------------------------------
+#
+# (value, was_explicit) distinguishes "not configured" (each agent uses its own
+# default) from an explicit true/false/null (overrides every agent uniformly).
+
+
+def test_parallel_tool_calls_not_in_default_config():
+    # No single default fits every agent (see module docstring above), so this
+    # key is intentionally absent from DEFAULT_CONFIG — load_config's merge
+    # must not mask "the user's config.yaml doesn't mention this key".
+    assert "parallel_tool_calls" not in DEFAULT_CONFIG
+
+
+def test_resolve_parallel_tool_calls_absent_is_unset():
+    assert resolve_parallel_tool_calls({}) == (None, False)
+
+
+def test_resolve_parallel_tool_calls_explicit_bools():
+    assert resolve_parallel_tool_calls({"parallel_tool_calls": True}) == (True, True)
+    assert resolve_parallel_tool_calls({"parallel_tool_calls": False}) == (False, True)
+
+
+def test_resolve_parallel_tool_calls_null_means_omit(caplog):
+    # Explicit null = "don't send the param" (provider default). This is the
+    # escape hatch for Amazon Bedrock, and is silent (not an invalid value) —
+    # explicit and distinct from "absent" even though both currently carry a
+    # value of None; was_explicit is what tells them apart.
+    with caplog.at_level(logging.WARNING, logger="openkb.config"):
+        assert resolve_parallel_tool_calls({"parallel_tool_calls": None}) == (None, True)
+    assert caplog.text == ""
+
+
+def test_resolve_parallel_tool_calls_rejects_non_bool(caplog):
+    # An invalid value (not true/false/null) degrades to the one value known
+    # to never break any provider — omit the setting — rather than to a fixed
+    # bool that could reproduce the exact failure (e.g. Amazon Bedrock) the
+    # user may have been trying to escape via this exact key.
+    with caplog.at_level(logging.WARNING, logger="openkb.config"):
+        assert resolve_parallel_tool_calls({"parallel_tool_calls": "true"}) == (None, True)
+    assert "parallel_tool_calls" in caplog.text
+
+
+def test_parallel_tool_calls_stash_roundtrip():
+    set_parallel_tool_calls(False, True)
+    assert get_parallel_tool_calls() == (False, True)
+    set_parallel_tool_calls(True, True)
+    assert get_parallel_tool_calls() == (True, True)
+    set_parallel_tool_calls(None, True)
+    assert get_parallel_tool_calls() == (None, True)
+    set_parallel_tool_calls(None, False)
+    assert get_parallel_tool_calls() == (None, False)
+
+
+def test_parallel_tool_calls_stash_default_is_unset():
+    # The raw stash default must mean "not configured", matching an absent key,
+    # so an agent built before _setup_llm_key runs defers to its own default.
+    set_parallel_tool_calls(None, False)
+    assert get_parallel_tool_calls() == resolve_parallel_tool_calls({})
+
+
+# --- resolve_model_settings ---------------------------------------------------
+
+
+def test_resolve_model_settings_uses_own_default_when_unset():
+    set_extra_headers({})
+    set_timeout(None)
+    set_parallel_tool_calls(None, False)
+    assert resolve_model_settings() == {
+        "extra_headers": None,
+        "extra_args": None,
+        "parallel_tool_calls": False,  # the function's own default
+    }
+    assert resolve_model_settings(default_parallel_tool_calls=None) == {
+        "extra_headers": None,
+        "extra_args": None,
+        "parallel_tool_calls": None,
+    }
+    assert resolve_model_settings(default_parallel_tool_calls=True) == {
+        "extra_headers": None,
+        "extra_args": None,
+        "parallel_tool_calls": True,
+    }
+
+
+def test_resolve_model_settings_explicit_value_overrides_every_default():
+    # An explicit config choice always wins over whatever default a specific
+    # caller would otherwise apply — the whole point of the escape hatch is
+    # that it works uniformly, regardless of which agent is asking.
+    set_extra_headers({"X-A": "1"})
+    set_timeout(1200.0)
+    set_parallel_tool_calls(None, True)  # explicit null: omit, for everyone
+    for default in (False, True, None):
+        assert resolve_model_settings(default_parallel_tool_calls=default) == {
+            "extra_headers": {"X-A": "1"},
+            "extra_args": {"timeout": 1200.0},
+            "parallel_tool_calls": None,
+        }
+
+    set_parallel_tool_calls(True, True)  # explicit true: allow parallel, for everyone
+    for default in (False, True, None):
+        assert (
+            resolve_model_settings(default_parallel_tool_calls=default)["parallel_tool_calls"]
+            is True
+        )
+
 
 def test_default_config_keys():
     assert "model" in DEFAULT_CONFIG