fix(mcp): always guard the MCP transport and validate on every managed connect

[waleedlatif1]

Summary

• McpClient always runs the transport on the SSRF-guarded fetch; it no longer falls back to the global fetch when no validated address is passed. A validated private address still pins, as before
• McpConnectionManager.connect validates the destination (validateMcpDomain + validateMcpServerSsrf) on every dial, reconnects included, instead of taking a caller-supplied resolvedIP
• Discovery only resolves env vars before handing off to the manager, so already-connected servers skip the DNS lookup
• Corrected the resolvedIP TSDoc and the client guard comment

Type of Change

• Bug fix

Testing

• New tests: client uses the guard with no address and pins a private one; manager validates before building a client, refuses without constructing one, and re-validates on reconnect. Confirmed they fail with the fix reverted
• lib/mcp + app/api/mcp suites pass (681), type-check, lint, check:audits, docs-manifest:check pass

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated
docs	Skipped		Sep 13, 2026 3:09am UTC

[greptile-apps]

Confidence Score: 5/5

The PR appears safe to merge; the changed paths consistently validate managed destinations and keep transport requests behind the SSRF guard.

Summary

• Validates domains and resolved destinations before constructing managed clients, including reconnects.
• Uses an SSRF-guarded transport by default and pins validated private addresses where policy permits.
• Separates environment-variable resolution from per-dial destination validation.
• Adds focused coverage for guarded transport selection, refused destinations, cleanup, and reconnect revalidation.

Diagram

sequenceDiagram
  participant S as MCP Service
  participant M as Connection Manager
  participant V as Domain/SSRF Validator
  participant C as MCP Client
  participant T as Guarded Transport
  participant R as MCP Server

  S->>S: Resolve URL/header environment variables
  S->>M: connect(resolvedConfig, userId, workspaceId)
  M->>V: validateMcpDomain(url)
  M->>V: validateMcpServerSsrf(url)
  V-->>M: Validated address
  M->>C: Construct with validated address
  C->>T: Create guarded or pinned fetch
  C->>R: Connect through guarded transport
  R-->>C: Connection / notifications
  R--xC: Transport closes
  C-->>M: onClose
  M->>M: Schedule reconnect
  M->>V: Revalidate destination
  V-->>M: Fresh validated address
  M->>C: Construct replacement client

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_{Reviews (1) · Last reviewed commit: "fix(mcp): always guard the MCP transport..."}