The three open agent protocols active in 2026 (Anthropic's Model Context Protocol, Google's Agent2Agent protocol contributed to the Linux Foundation, and Meta's Llama Stack) are not on a convergence trajectory, and the four major proprietary agentic platforms (Microsoft Copilot Agent, Salesforce Agentforce, SAP Joule, ServiceNow Now Assist) do not adopt any of the three as first-class defaults. The cost of being wrong on the model choice is low because swapping models is a configuration change. The cost of being wrong on the protocol choice is high because the locked asset is the tool inventory — the MCP servers, A2A endpoints, Llama Stack tool plugins, or proprietary extensions the customer has built or commissioned — and re-platforming the tool inventory is the long-tail engineering bill. Standard 2026 agentic AI MSAs do not include the three procurement clauses (protocol portability disclosure, tool inventory exit terms, protocol-roadmap commitment) that would price the protocol-roadmap optionality back to the customer.

Claim is scoped to the protocol-lock-in dimension of the 2026 enterprise agentic AI procurement decision. Does not assert the protocols are technically inferior or superior to one another — asserts that the fragmentation creates re-platform cost that most procurement processes are not modelling. 60-day review cadence. Trigger conditions: (1) MCP, A2A, and Llama Stack publish a converged or interoperable spec — would move toward Partial because the protocol fragmentation is closing structurally; (2) one of the four major proprietary platforms (Microsoft, Salesforce, SAP, ServiceNow) adopts MCP or A2A as a first-class default — would shift the lock-in calculus materially and reduce the per-platform tool-wrapper cost; (3) a published 2026 enterprise re-platform with a cost figure attached — would empirically anchor the 'tool inventory is the locked asset' argument; (4) an OWASP, NIST, or ENISA control set on agent-protocol risk — would change the audit picture and likely accelerate adoption of the three procurement clauses; (5) Llama Stack ecosystem growth (server count, library count, third-party tool support) reaching parity with MCP — would change the picking calculus for self-hosted-aligned customers.