BerriAI/litellm · error · ValueError

agent_config must be a list of dictionaries

Error message

agent_config must be a list of dictionaries

What it means

Raised by AgentRegistry.load_agents_from_config when the agent_config value from config.yaml is neither a list nor contains non-dict entries — the loader expects a sequence of per-agent mapping objects. This is a config-shape error at proxy startup, before any agent registration happens; the offending agent_config block must be rewritten as a list of dicts.

Source

Thrown at litellm/proxy/agent_endpoints/agent_registry.py:170

        return self.config_agent_legacy_ids.get(agent_id, agent_id)

    def load_agents_from_config(self, agent_config: Sequence[AgentConfig] | None = None):
        """
        Register the agents declared in config.yaml and remember them for later rebuilds.

        A config entry is skipped when its ``agent_name`` is already registered, so a
        database record always wins over a config entry that reuses its name and the
        registry never holds two agents under one name. Enforcing that here rather than
        in the caller keeps the guarantee independent of the order the two sources load
        in. Passing ``None`` leaves the remembered agents untouched; passing an empty
        sequence clears them.
        """
        if agent_config is None:
            return

        for agent_config_item in agent_config:
            if not isinstance(agent_config_item, dict):
                raise ValueError("agent_config must be a list of dictionaries")

        self.config_agents = tuple(agent_config)
        self.config_agent_legacy_ids = MappingProxyType(
            {
                self._create_legacy_agent_id(agent_config_item): self._create_agent_id(agent_config_item)
                for agent_config_item in agent_config
                if agent_config_item.get("agent_name") and agent_config_item.get("agent_card_params")
            }
        )

        for agent_config_item in agent_config:
            agent_name = agent_config_item.get("agent_name")
            agent_card_params = agent_config_item.get("agent_card_params")
            if not all([agent_name, agent_card_params]):
                continue

            if any(agent.agent_name == agent_name for agent in self.agent_list):
                continue

View on GitHub (pinned to 77b7c6c40c)

Solutions

1. Pass agent_config as a list of dictionaries.

Example fix

agent_config=[{'agent_name':'a', ...}]

When it happens

Trigger: Thrown at litellm/proxy/agent_endpoints/agent_registry.py:170 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of BerriAI/litellm@77b7c6c40c (2026-08-18). Data as JSON: /api/errors/1752eb53d8e31951. Report an issue: GitHub.