mastra-ai/mastra · error · HTTPException

Version with id ${from} not found for MCP client ${mcpClient

Error message

Version with id ${from} not found for MCP client ${mcpClientId}

What it means

The 'from' version exists but its mcpClientId differs from the path's mcpClientId, so the handler throws a 404 scoped to the client. This prevents comparing versions across different MCP clients.

Source

Thrown at packages/server/src/server/handlers/mcp-client-versions.ts:468

      const storage = mastra.getStorage();

      if (!storage) {
        throw new HTTPException(500, { message: 'Storage is not configured' });
      }

      const mcpClientStore = await storage.getStore('mcpClients');
      if (!mcpClientStore) {
        throw new HTTPException(500, { message: 'MCP clients storage domain is not available' });
      }
      const mcpClient = await mcpClientStore.getById(mcpClientId);
      assertStoredResourceScope(mcpClient, await getStoredResourceScope(mastra, requestContext));

      const fromVersion = await mcpClientStore.getVersion(from);
      if (!fromVersion) {
        throw new HTTPException(404, { message: `Version with id ${from} not found` });
      }
      if (fromVersion.mcpClientId !== mcpClientId) {
        throw new HTTPException(404, {
          message: `Version with id ${from} not found for MCP client ${mcpClientId}`,
        });
      }

      const toVersion = await mcpClientStore.getVersion(to);
      if (!toVersion) {
        throw new HTTPException(404, { message: `Version with id ${to} not found` });
      }
      if (toVersion.mcpClientId !== mcpClientId) {
        throw new HTTPException(404, {
          message: `Version with id ${to} not found for MCP client ${mcpClientId}`,
        });
      }

      const fromConfig = extractConfigFromVersion(
        fromVersion as unknown as Record<string, unknown>,
        MCP_CLIENT_SNAPSHOT_CONFIG_FIELDS,
      );

View on GitHub (pinned to 75dd419e61)

Solutions

Pass both from and to ids belonging to the same mcpClientId as in the path.
Re-fetch each client's version list when switching clients in the UI.
Assert version.mcpClientId matches before issuing the compare request.

Defensive patterns

Strategy: validation

Validate before calling

const from = versions.find(v => v.id === fromId);
if (from?.mcpClientId !== clientId) throw new Error('from version belongs to a different MCP client');

Try / catch

try { await compare(from, to); } catch (e) { if (e.status === 404 && /not found for MCP client/.test(e.message)) { /* use ids owned by this client */ } else throw e; }

Prevention

Scope version lists per client and never merge them
Reset selection state when switching clients
Assert parent ownership before cross-referencing ids

When it happens

Trigger: GET /stored/mcp-clients/:mcpClientId/versions/compare?from=<id>&to=<id> where from belongs to another MCP client.

Common situations: Scripts iterating multiple clients that reuse a single versions list; copy-pasted compare URLs mixing clients; UI state carrying a from-selection across a client switch.

Related errors

AI-assisted analysis of mastra-ai/mastra@75dd419e61 (2026-08-30). Data as JSON: /api/errors/935a2369172a14b5. Report an issue: GitHub.