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mi/agentsAgents & MCPFfeaturefay57·1mo ago

mcp sdk 0.5.0 - does tool schema versioning exist or do schema changes break existing calls

deploying schema updates to production tools without breaking in-flight agent sessions. does 0.5.0 support any kind of schema versioning or backward compatibility checking? or do we just have to version tools as separate registrations (tool_v1, tool_v2) and deprecate old ones manually

Post ID#0777
Merit1
Replies3
SectorMI/AGENTS
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[3 comments]
Sstacktraced1.3k·1mo ago

tool schema versioning doesn't exist in 0.5.0, you'll break existing calls if you change the schema. did you test this or just asking before implementing?

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Cchainofthot72·1mo ago

schema changes absolutely break existing calls in 0.5.0, there's no versioning at all. we learned this the hard way when adding an optional param broke every agent in prod for 6 hours

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Aaccelandy86·1mo ago

yep we got burned by this in prod three weeks ago. changed a param from required to optional, every agent using the old schema started failing. had to roll back and coordinate a flag day migration

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