What causes "HTTP error! status: ${response.status}" in langflow-ai/langflow?

Read the server log: the handler calls logger.aexception with 'Error listing project tools: {e}' — the traceback names the exact field or operation that failed.

langflow-ai/langflow · error · Error

HTTP error! status: ${response.status}

Error message

HTTP error! status: ${response.status}

What it means

Generic 500 raised by the catch-all handler of the project-tools listing endpoint in the project MCP API (mcp_projects.py). Any exception while collecting tools, decrypting auth settings, or constructing AuthSettings bubbles up here and the raw exception text is echoed to the client. Typical causes are malformed/undecryptable auth_settings on the Folder row or Pydantic validation failures in AuthSettings.

Source

Thrown at src/frontend/src/controllers/API/index.ts:94

  },
  tags: string[],
  publicFlow = false,
): Promise<FlowType> {
  try {
    const response = await api.post(`${getBaseUrl()}store/components/`, {
      name: newFlow.name,
      data: newFlow.data,
      description: newFlow.description,
      is_component: newFlow.is_component,
      parent: newFlow.parent,
      tags: tags,
      private: !publicFlow,
      status: publicFlow ? "Public" : "Private",
      last_tested_version: newFlow.last_tested_version,
    });

    if (response.status !== 201) {
      throw new Error(`HTTP error! status: ${response.status}`);
    }
    return response?.data;
  } catch (error) {
    console.error(error);
    throw error;
  }
}

export async function getStoreComponents({
  component_id = null,
  page = 1,
  limit = 9999999,
  is_component = null,
  sort = "-count(liked_by)",
  tags = [],
  liked = null,
  isPrivate = null,
  search = null,

View on GitHub (pinned to 976ec789d2)

Solutions

Read the server log: the handler calls logger.aexception with 'Error listing project tools: {e}' — the traceback names the exact field or operation that failed.
Inspect the project row's auth_settings JSON in the DB for stale/unexpected keys; re-save the MCP auth settings from the UI to rewrite them in the current schema.
If decryption fails after a secret-key change, clear the stored auth settings for that project and re-enter credentials.
If AuthSettings validation is the cause, align the masked payload with the current AuthSettings model (only pass fields it defines).

Defensive patterns

Strategy: try-catch

Try / catch

try:
    tools = await client.list_project_tools(project_id)
except httpx.HTTPStatusError as e:
    if e.response.status_code == 500:
        log_server_detail(e.response.json().get("detail"))  # echoes the inner exception
    raise

Prevention

Always re-save MCP auth settings from the UI after upgrading Langflow so the stored schema matches AuthSettings.
Avoid rotating LANGFLOW_SECRET_KEY without a plan for re-encrypting stored secrets.
Surface the 500 detail in bug reports — it contains the underlying exception text.

When it happens

Trigger: GET /api/v1/mcp/projects/{project_id}/tools (or the list-tools route ending at this handler) where: project.auth_settings contains keys not accepted by AuthSettings, decryption of stored secrets fails (changed SECRET_KEY), or the tool-collection coroutine raises.

Common situations: Rotating LANGFLOW_SECRET_KEY so previously encrypted oauth_client_secret/api_key values no longer decrypt; upgrading Langflow so AuthSettings gained/renamed fields while old DB rows keep the old shape; a component in the project failing to import during tool discovery.

Related errors

AI-assisted analysis of langflow-ai/langflow@976ec789d2 (2026-08-14). Data as JSON: /api/errors/467cdef5029da46a. Report an issue: GitHub.