HKUDS/nanobot · error · RuntimeError

required session is not active

Error message

required session is not active

What it means

Error "required session is not active" thrown in HKUDS/nanobot.

Source

Thrown at nanobot/agent/loop.py:1802

        )

    async def _restore_turn(self, ctx: TurnContext) -> None:
        """Restore checkpoint / pending user turn; reference non-image attachments."""
        msg = ctx.msg

        if ctx.kind is TurnKind.USER and msg.media:
            new_content, image_paths = reference_non_image_attachments(
                msg.content,
                msg.media,
            )
            ctx.msg = dataclasses.replace(msg, content=new_content, media=image_paths)
            msg = ctx.msg

        if ctx.session is None:
            if msg.require_existing_session:
                ctx.session = self.sessions.get_cached(ctx.session_key)
                if ctx.session is None:
                    raise RuntimeError("required session is not active")
            else:
                ctx.session = self.sessions.get_or_create(ctx.session_key)
        session = ctx.session
        ctx.ephemeral = ctx.ephemeral or not session.policy.persist
        tools = ctx.tools or self.tools
        if session.policy.disabled_tools:
            restricted = ToolRegistry()
            for name in tools.tool_names:
                tool = tools.get(name)
                if name not in session.policy.disabled_tools and tool:
                    restricted.register(tool)
            tools = restricted
        ctx.tools = tools

        if ctx.kind is TurnKind.SYSTEM:
            logger.info("Processing system message from {}", msg.sender_id)
        elif session.policy.log_content:
            preview = msg.content[:80] + "..." if len(msg.content) > 80 else msg.content

View on GitHub (pinned to 42f37dc4c0)

When it happens

Trigger: Thrown at nanobot/agent/loop.py:1802 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of HKUDS/nanobot@42f37dc4c0 (2026-08-26). Data as JSON: /api/errors/014611b1c4c4508b. Report an issue: GitHub.