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1.10: split the SDK bundle, so a server doesn't set up subsystems it doesn't use #950
Description
Follow-up to the 1.10.9 performance work: #914, #919 to #925, #932, and #934 to #943.
What's left
@frontmcp/sdk's CommonJS bundle is 2 MB of source. Compiling it takes about 16 ms at startup, and its root re-exports force about 10 to 15 ms of module setup for every subsystem, whether the server uses it or not.
Upper bounds we measured against 1.10.9-rc.4, using hacks that break public behavior:
| Skipped at startup | HTTP | stdio |
|---|---|---|
| Setup of jobs, workflows, channels, remote MCP and the ESM loader | −1.9 ms | −1.8 ms |
| Loading and registering the 8 OAuth flows in a public-mode server | −3.1 ms | −3.6 ms |
| Task setup | 0 | 0 |
Doing this while keeping the root exports and flow registration as they are would need a different bundle layout. A post-build rewrite of esbuild's output would be too fragile.
Proposal
Make the CommonJS root exports lazy, as getters for the subsystems a server may never use, or split the SDK into subsystem chunks that load on first use. Expected: about 5 ms and 1 to 2 MB.
Acceptance
- The public exports are the same.
- Hooks and plugins that target any flow behave as before, including OAuth flows in public mode.
- Worker and browser builds keep working: the bundle-size and worker-export-condition tests pass.
- Cold start and RSS are measured before and after with the benchmark harness.
Activity