A governed fleet of specialized agents that discovers legacy data estates, reconstructs lineage, plans migration, validates outcomes, recovers from failure, and keeps production cutover under human authority.
Schemas, procedures, transformations, schedules, ownership and policy live in different systems. The estate is real, and no single account of it is trustworthy.
A governed fleet of specialized agents that discovers legacy data estates, reconstructs lineage, plans migration, validates outcomes, recovers from failure, and keeps production cutover under human authority.
Enterprise migration is a decision problem before it is a data-copy problem.
Legacy estates are rarely described in one reliable place. Catalogs show schemas, but SQL and stored procedures hide transformations. Schedulers encode timing and dependencies. Comments may be stale or adversarial. Sensitive data carries access and residency constraints. Validation logic differs by team, while cutover often depends on manual evidence assembled too late.
01
Hidden dependencies make local changes break downstream reports and services.
02
Dialect and type incompatibilities surface late, often during execution.
03
Model reasoning is unsafe when it is allowed to directly authorize sensitive actions.
04
Validation frequently stops at row counts instead of checking schemas, hashes, aggregates and null profiles.
05
Repeated failures are rediscovered because remediation knowledge is not durable.
06
Cutover authority is fragile when the approval is not bound to the exact migration plan.
Discovery
Lineage
Risk
Planner
Migration
Reconciliation
Recovery
Approval
Cutover
Evidence
Discovery
Lineage
Risk
Planner
Migration
Reconciliation
Recovery
Approval
Cutover
Evidence
S.02The sequence
A control tower for the decisions around migration.
Migration Control Tower turns the migration lifecycle into a durable, governed state machine. Specialized agents interpret legacy evidence and propose actions. Deterministic services enforce authorization, idempotency, budgets, validation results, approval integrity and legal state transitions. Cloud Run Jobs move rows independently of the reasoning layer. A human operator retains authority over production cutover.
01REQUESTED
The estate is dark
Legacy estates are rarely described in one reliable place. Catalogs show schemas, but SQL and stored procedures hide transformations. Schedulers encode timing and dependencies. Comments may be stale or adversarial. Nothing here can yet be trusted as a single account of what exists.
02DISCOVERED
Discovery sweeps the floor
The Discovery agent catalogs schemas, SQL, DAGs, connection posture and ownership evidence. The adapter — not the model — owns connection validation and the extraction of database facts. A model cannot invent a table name or a measured row count.
03ANALYZED · RISK_ASSESSED · PLANNED
The fleet comes up
Lineage reconstructs dependencies across databases, transformations and schedules. Risk classifies PII, dialect risk and policy exposure. Planner builds ordered targets, mappings, validation checks and remediation notes. Agents are resolved by capability through approved, versioned AgentCards — never hard-coded into the workflow.
04MIGRATING · VALIDATING · FAILED
Flow, and fracture
Cloud Run Jobs move rows independently of the reasoning layer. When validation fails, the break is loud. Failure is a designed path, not an exception: the recovery loop builds an incident from deterministic evidence and uses lineage to locate the responsible pipeline.
05PASSED · READY_FOR_APPROVAL
Nothing passes unproven
Schema, count, hash, aggregate, duplicate and null-profile checks run deterministically. A run cannot reach approval until every required check passes. The approval service verifies the human identity, enforces separation of duties, and binds the token to the migration plan hash.
06APPROVED · CUTOVER · COMPLETE
Cutover, under authority
The Cutover agent can consume a valid approval token but cannot issue one. Completion is derived from recorded state transitions rather than from the interface. Every action is scoped, every transition is durable, every validation result is reproducible.
01
02
03
04
05
06
REQUESTED
The estate is dark
Legacy estates are rarely described in one reliable place. Catalogs show schemas, but SQL and stored procedures hide transformations. Schedulers encode timing and dependencies. Comments may be stale or adversarial. Nothing here can yet be trusted as a single account of what exists.
DISCOVERED
Discovery sweeps the floor
The Discovery agent catalogs schemas, SQL, DAGs, connection posture and ownership evidence. The adapter — not the model — owns connection validation and the extraction of database facts. A model cannot invent a table name or a measured row count.
ANALYZED · RISK_ASSESSED · PLANNED
The fleet comes up
Lineage reconstructs dependencies across databases, transformations and schedules. Risk classifies PII, dialect risk and policy exposure. Planner builds ordered targets, mappings, validation checks and remediation notes. Agents are resolved by capability through approved, versioned AgentCards — never hard-coded into the workflow.
MIGRATING · VALIDATING · FAILED
Flow, and fracture
Cloud Run Jobs move rows independently of the reasoning layer. When validation fails, the break is loud. Failure is a designed path, not an exception: the recovery loop builds an incident from deterministic evidence and uses lineage to locate the responsible pipeline.
PASSED · READY_FOR_APPROVAL
Nothing passes unproven
Schema, count, hash, aggregate, duplicate and null-profile checks run deterministically. A run cannot reach approval until every required check passes. The approval service verifies the human identity, enforces separation of duties, and binds the token to the migration plan hash.
APPROVED · CUTOVER · COMPLETE
Cutover, under authority
The Cutover agent can consume a valid approval token but cannot issue one. Completion is derived from recorded state transitions rather than from the interface. Every action is scoped, every transition is durable, every validation result is reproducible.
The sequence
01 / 06
S.03Three planes
Interpretation, execution and authority are separate systems.
Agents reason about metadata, risk, plans and evidence.
The orchestrator advances a run through legal states and resolves approved providers by capability. AgentCards are versioned, signed and pinned to each run. Firestore stores durable run state and idempotency claims. Pub/Sub delivers stage events with dead-letter handling.
· Orchestrator
· Agent Registry
· Policy engine
· Durable state
· Idempotent messaging
· Cross-run memory
II
Data plane
Managed jobs move rows; deterministic validators compare source and target.
Cloud Run Jobs execute bounded table movement. In the measured path, three jobs loaded customers, orders and tags from Cloud SQL for PostgreSQL into BigQuery. The executor reports row counts, byte counts, duration and completion evidence independently of the agent control plane.
· Cloud Run Jobs
· Cloud SQL for PostgreSQL
· Cloud Storage staging
· BigQuery
· Deterministic validators
III
Human plane
An authorized operator approves a token cryptographically bound to the plan.
A run cannot reach approval until every required deterministic validation passes. The approval service checks the human identity, verifies separation of duties, and binds the token to the migration plan hash. The Cutover agent can consume a valid token but cannot issue one.
· Firebase Authentication
· Estate-scoped roles
· Separation of duties
· Plan-hash binding
· Append-only decisions
S.04The fleet
Seven specialists, resolved by capability.
01
Discovery
Sees the estate
Catalogs schemas, SQL, DAGs, connection posture and ownership evidence.
· Schema inventory
· SQL and stored procedures
· Scheduling artifacts
· Connection posture
· Ownership evidence
02
Lineage
Finds what depends on what
Reconstructs dependencies across databases, transformations and schedules.
· Asset relationships
· Upstream and downstream impact
· Proven vs. proposed edges
· PII-aware impact map
03
Risk
Classifies exposure
Classifies PII, dialect risk, criticality and policy exposure.
· PII classification
· Dialect incompatibility
· Criticality scoring
· Policy exposure
04
Planner
Orders the work
Builds ordered targets, mappings, validation checks and remediation notes.
· Ordered targets
· Column mappings
· Validation checks
· Budgets
· Recovery options
05
Validation
Decides what passed
Runs schema, count, hash, aggregate, duplicate and null-profile checks.
· Schema equivalence
· Row counts
· Content hashes
· Aggregates
· Duplicates
· Null profiles
06
Cutover
Executes under authority
Consumes human approval, performs the governed cutover, and monitors health.
· Approval consumption
· Governed cutover
· Row-count health
· Hash health
· Monitoring
07
Finance Impact
Follows the cost
Finds affected reports and downstream consumers through wildcard capability discovery.
The policy engine receives structured identity, action, resource class and run context. It never receives free-text legacy content. A hostile table comment therefore has no channel into an authorization decision. Unsafe raw-PII access is denied deterministically, secrets remain references until runtime, handlers are idempotent, and approval cannot be reused after the plan changes.
When validation fails, the recovery path builds an incident from deterministic evidence and uses lineage to locate the responsible pipeline. Gemini can explain a bounded root-cause hypothesis; ordinary code selects and applies only an approved remediation. Confirmed fixes are written to cross-run memory, but every future reuse still requires fresh validation.