The Fastest Way to Get Locked Into an AI Vendor Is to Ship Before You Record What Depends on It
Create an AI vendor exit plan covering prompts, tools, data, evaluations, model behavior, contracts, and migration rehearsals.
Lock-in grows in the parts no one inventories
Vendor lock-in is not only a model API format. It can live in prompt templates, proprietary file stores, fine-tuned weights, evaluation tools, agent runtimes, managed vector databases, identity integrations, and assumptions embedded in product behavior. Teams often discover these dependencies when a price changes, a feature is deprecated, a contract is renegotiated, or a provider has an outage.
Trying to make every component interchangeable from day one can create its own complexity. A giant abstraction layer may hide model-specific features and slow delivery. The practical goal is to know what would be difficult to move, preserve the assets that matter, and maintain enough evidence to compare alternatives.
Inventory your dependency surface
List each provider and the capability used: text generation, embeddings, reranking, speech, vision, tools, hosting, logging, or data storage. Record model identifiers, versions, region, contract owner, data categories, pricing unit, rate limits, and deprecation notices. Note which parts are provider-specific and which are standard application data.
Keep prompts, schemas, evaluation sets, and business rules in version control where appropriate. Store source documents and metadata in formats you can export. Preserve original data separately from embeddings, because embeddings may need to be regenerated with a different model. Record how indexes are built so a migration does not depend on undocumented manual steps.
Document capability differences that influence user-visible behavior: context size, tool calling, structured output, streaming, refusal, and multimodal input. Portability does not mean identical behavior. The difference itself should be visible in the migration plan.
Keep the right boundaries portable
Use an internal interface for common request concepts, such as task type, data classification, output schema, and timeout. Keep provider-specific options accessible when needed instead of forcing every provider into the lowest common denominator. Validate outputs and permissions in your own application so important rules do not live only in a vendor console.
Separate orchestration state from provider run IDs where feasible. Store enough information to reconstruct a task and continue or restart it. Keep user data exportable and avoid making a provider's proprietary memory format the only copy of important context.
For agent runtimes, define tool contracts and state transitions independently. A provider may host execution, but your application should still own authorization, approval, and business invariants. This reduces migration risk and makes incident response clearer.
Make an exit plan concrete
Define what would trigger a migration: sustained cost increase, unmet availability, quality regression, contractual change, or a required capability elsewhere. Identify a candidate alternate and an owner. Estimate data export, re-embedding, prompt adaptation, evaluation, compliance review, and user communication effort.
Run a small migration rehearsal on a low-risk task. Export inputs, rebuild indexes if necessary, run the evaluation set, compare cost and quality, and test rollback. Record what was unexpectedly provider-specific. A rehearsal often reveals dependencies that a diagram misses.
Negotiate data access, retention, termination assistance, and deletion terms before a crisis. Confirm that contract language matches the operational settings. Maintain an inventory of provider notices and renewal dates so a deprecation does not become a weekend emergency.
Avoid abstraction theater
Do not build a universal interface for features you do not use. Start with the boundary that protects the highest-value assets: your data, evaluation criteria, permissions, and product logic. Add adapters when a real second implementation is being tested. Keep a clear path to use a provider-specific feature where it improves outcomes, with the dependency documented.
Vendor independence is not a binary state. It is a set of known migration costs and preserved choices. Inventory your dependencies, keep critical assets under your control, test one plausible route out, and make the exit trigger explicit. You may choose to stay with a provider; the difference is that the decision remains informed rather than accidental.
Review this plan after a major product launch, contract renewal, model deprecation notice, or change in data classification. Keep a short list of the hardest-to-move components and give each one an owner. A practical exit plan can be one page; its value comes from being current and rehearsed, not from being an elaborate architecture document nobody updates.
Make the exit decision actionable by identifying the minimum acceptable alternate, not a theoretical substitute for every feature. A modest migration that preserves the highest-value workflow can be enough to create negotiating leverage and continuity. Record which behaviors cannot yet move, who accepts that dependency, and what event would make the team invest in closing the gap.