LangChain (via @langchain/langgraph createReactAgent) creates / updates /
deletes Linear labels through Relayfile. Schema-validated, with comprehensive
op-status proof (writeback.provider=linear → op succeeded → real Linear
UUID in providerResult.externalId).
agent-relay cloud login
cd examples/integrations/langchain-linear-writeback
npm install
CLOUD_WORKSPACE_ID=<your-app-uuid> npm run smokeThen for the interactive agent:
ANTHROPIC_API_KEY=sk-ant-… npm run devFor CI: set CLOUD_API_ACCESS_TOKEN (and optionally CLOUD_API_REFRESH_TOKEN,
CLOUD_API_URL).
Every smoke run creates ONE real Linear label and deletes it before exit.
Test labels are prefixed relayfile-writeback-test. See
vercel-ai-sdk-linear-writeback/README.md for the full contract details.
Honest answer in packages/agents/README.md: the MCP wins for one-shot single-provider work; @relayfile/agents is structurally better as integrations and agents compound.