Support Message array for instructions in Agent constructor

[firebuzz-dev]

We are not able to pass system message like below into instructions key in agent constructor.

const systemMessage = [{role:"system", content:"long content to cache"}]

If we can do this we can put cache control for anthropic models.

Current workaround is not passing in the constructor but passing manually in contextHandler.

[ianmacartney]

How big of a deal is it to use the contextHandler for this? I know it's not ideal, but part of the hope there was to have a more flexible option that gives all the power. Also open to a PR making the instructions a string | ModelMessage[] - likely wouldn't be too crazy, since most of that logic is centralized

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On Thu, Nov 27, 2025 at 10:34 AM firebuzz-dev ***@***.***> wrote: *firebuzz-dev* created an issue (get-convex/agent#192) <#192> We are not able to pass system message like below into instructions key in agent constructor. const systemMessage = [{role:"system", content:"long content to cache"}] If we can do this we can put cache control for anthropic models. Current workaround is not passing in the constructor but passing manually in contextHandler. — Reply to this email directly, view it on GitHub <#192>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AACZQW7Q6PIUSYVMGORUDJT36472VAVCNFSM6AAAAACNMWYNYWVHI2DSMVQWIX3LMV43ASLTON2WKOZTGY3TENRXHA4DEMI> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>