Framework · 2023–now · AI Present

LLM app frameworks

LangChain-class glue mutated into MCP clients and thin wrappers around vendor APIs. The durable pieces are still boring: evals, retrieval, and product UX.

How LLM app frameworks mutated

LLM frameworks mutated because the models underneath changed faster than semver. The fad was treating prompt glue as architecture. By late 2026 the category consolidated — first-party harnesses and MCP adapters winning the product surface, orchestration repos becoming clients of those protocols. What sticks looks like observability and eval pipelines, not chain-of-thought cosplay.

Case studies

Patterns

2022–now

AI Present

Part of the AI Present era (2022–now).

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Related

Platform · 2022–now

Vector DB gold rush

Mutated

Specialized embedding stores sold as the default. Mid-market folded back into Postgres — after the vendor tour.

Language · 1991–now

Python

Stuck

From scripting glue to the default language of data and AI. Readability as a growth strategy.

Practice · 2021–now

AI pair programming

Stuck

Coding agents that edit the repo — now table stakes. Generation outran review capacity; ownership is the bottleneck.

Framework · 2023–now

LLM orchestration frameworks

Mutated

Chains, tools, memory, and agents as a framework — LangChain-class glue sold as architecture. Fatigue was real; the repos became MCP clients, not tombstones.

$ Teams adopted chain/agent frameworks before they had a single reliable tool call. Abstraction layers multiplied while prompt quality stayed flat.

Practice · 2023–now

RAG as default architecture

Mutated

Retrieval-augmented generation as the answer to every knowledge problem — then "just stuff the window" as the counter-fad. Often right; often Postgres with pgvector would suffice.

$ Teams stood up vector pipelines, chunking strategies, and rerankers before asking if fine-tuning or a SQL query would answer the question. Retrieval infra became the product.

Platform · 2025–now

Vendor agent APIs

Mutated

The Codex/Claude loop as a product SKU — durable sessions, compaction, subagents, and a sandbox you do not own.

$ Teams replaced a weekend of LangGraph glue with a managed session API, then discovered residency, recovery, and kill switches all live on the vendor side of the harness.

Architecture · 2024–now

Context / tool protocols

Stuck

Standard ways for models to talk to tools and data — MCP after the 2026 stateless rewrite, not one-off plugin snowflakes.

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