feat(mcp): authorize GCP backend endpoint

[xnoto]

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Summary

Adds makeitwork-gcp to the per-backend MCP Access application set in cf-access-mcp.tf, creating the fail-closed Access application for mcp-makeitwork-gcp.makeitwork.cloud under the existing MCP Gateway service-token and GitHub-admin policies.

No new service token, tunnel identity, DNS record, workload route, provider version, workflow, or secret is created here. kustomize-cluster owns the later TunnelBinding route and must not merge it until this PR has merged and its environment-gated apply has completed.

Fixes # N/A — owner-directed direct GCP MCP endpoint.

Type of change

• Infrastructure (OpenTofu root or module)

Validation

• Required pull-request checks pass — opentofu run 34326070590 (test and plan) succeeded.
• Generated or centrally distributed files were regenerated by their owning automation, not hand-edited — N/A; the for_each resource is already documented in README.md, and adding one list key does not change the generated resource inventory. CI terraform docs passed unchanged.
• The redacted plan comment shows exactly Plan: 1 to add, 0 to change, 0 to destroy: cloudflare_zero_trust_access_application.mcp_gateway_backend["makeitwork-gcp"] for domain mcp-makeitwork-gcp.makeitwork.cloud.

Pre-PR review evidence:

• Adversarial review: ADVANCE; no Critical/High findings; required the PR plan to show only the intended Access application (confirmed above).
• Infrastructure security review: ADVANCE; two Low notes — the shared non-expiring service token's reach expands by design to this additional read-only backend, and route ordering is an operational dependency.
• Release-readiness review (GLM fallback after the Kimi release-engineer delegation hit a provider quota): ADVANCE; ordering, rollback, and consumer-PR correction gates recorded.

Impact and rollout

Producer: tfroot-cloudflare is the canonical Cloudflare Access owner. Consumer: the existing ToolHive makeitwork-gcp backend and a later kustomize-cluster TunnelBinding route.

Ordered delivery:

1. PR CI validates and plans this Access-only change. (passed)
2. After review and explicit merge approval, merge to main; approve the environment-gated production apply.
3. Confirm the Access application for mcp-makeitwork-gcp.makeitwork.cloud exists.
4. Only then open/merge the held kustomize-cluster route PR (branch feat/mcp-gcp-direct-endpoint, whose README carries an explicit do-not-merge gate).
5. The three corrected xnoto client PRs (codex-config#5, claude-config#5, opencode-config#17) add direct makeitwork-gcp entries; merge only after the route is live.

Rollback: remove the TunnelBinding route first, then revert this list addition through a new reviewed PR and environment-gated apply.

Safety and secrets

• Contains no plaintext secrets, decrypted SOPS values, state files, kubeconfigs, tokens, or private endpoints
• No local OpenTofu init/plan/apply/destroy/import/state operations were run or claimed — plans come from pull-request checks
• Breaking or irreversible effects are described above with rollback notes

AI-assisted change: an OpenCode agent materially produced this change. Reviewers should verify the list key, expected plan delta, and that no workload DNS ownership moves into this root.

[github-actions]

OpenTofu Test

OpenTofu test passed.

View the workflow run.

View run output

Terraform validate.......................................................Passed
Terraform validate with tflint...........................................Passed
Checkov..................................................................Passed
Terraform fmt............................................................Passed
Terraform docs...........................................................Passed
Detect hardcoded secrets.................................................Passed
check for case conflicts.................................................Passed
check for merge conflicts................................................Passed
check for broken symlinks............................(no files to check)Skipped
check vcs permalinks.....................................................Passed
detect destroyed symlinks................................................Passed
detect private key.......................................................Passed
fix end of files.........................................................Passed
mixed line ending........................................................Passed
trim trailing whitespace.................................................Passed
don't commit to branch..................................................Skipped
check for added large files..............................................Passed

[github-actions]

OpenTofu Plan

OpenTofu plan passed.

View the workflow run.

View run output

OpenTofu will perform the following actions:

  # cloudflare_zero_trust_access_application.mcp_gateway_backend["makeitwork-gcp"] will be created
  + resource "cloudflare_zero_trust_access_application" "mcp_gateway_backend" {
      + account_id                 = (sensitive value)
      + allowed_idps               = [
          + "e584ea47-1251-4939-95f4-4daf4a58cd31",
        ]
      + app_launcher_visible       = true
      + aud                        = (known after apply)
      + destinations               = (known after apply)
      + domain                     = "mcp-makeitwork-gcp.makeitwork.cloud"
      + http_only_cookie_attribute = true
      + id                         = (known after apply)
      + name                       = "MCP makeitwork-gcp"
      + policies                   = [
          + {
              + decision   = "non_identity"
              + include    = [
                  + {
[REDACTED: potentially sensitive plan output]
[REDACTED: potentially sensitive plan output]
                        }
                    },
                ]
              + name       = "mcp-gateway-clients"
              + precedence = 1
            },
          + {
              + decision   = "allow"
              + include    = [
                  + {
                      + group = {
                          + id = "e0d9e873-31d7-4536-9234-3dad8a99d84d"
                        }
                    },
                ]
              + name       = "makeitworkcloud-admins"
              + precedence = 2
            },
        ]
      + self_hosted_domains        = (known after apply)
      + session_duration           = "24h"
      + type                       = "self_hosted"
    }

Plan: 1 to add, 0 to change, 0 to destroy.
OpenTofu will perform the following actions:

  # cloudflare_zero_trust_access_application.mcp_gateway_backend["makeitwork-gcp"] will be created
  + resource "cloudflare_zero_trust_access_application" "mcp_gateway_backend" {
      + account_id                 = (sensitive value)
      + allowed_idps               = [
          + "e584ea47-1251-4939-95f4-4daf4a58cd31",
        ]
      + app_launcher_visible       = true
      + aud                        = (known after apply)
      + destinations               = (known after apply)
      + domain                     = "mcp-makeitwork-gcp.makeitwork.cloud"
      + http_only_cookie_attribute = true
      + id                         = (known after apply)
      + name                       = "MCP makeitwork-gcp"
      + policies                   = [
          + {
              + decision   = "non_identity"
              + include    = [
                  + {
[REDACTED: potentially sensitive plan output]
[REDACTED: potentially sensitive plan output]
                        }
                    },
                ]
              + name       = "mcp-gateway-clients"
              + precedence = 1
            },
          + {
              + decision   = "allow"
              + include    = [
                  + {
                      + group = {
                          + id = "e0d9e873-31d7-4536-9234-3dad8a99d84d"
                        }
                    },
                ]
              + name       = "makeitworkcloud-admins"
              + precedence = 2
            },
        ]
      + self_hosted_domains        = (known after apply)
      + session_duration           = "24h"
      + type                       = "self_hosted"
    }

Plan: 1 to add, 0 to change, 0 to destroy.