fix: cap inbound message size — one oversized line could exhaust memory - #3
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readMessage accumulated a line without bound (bufio.ErrBufferFull → keep appending), so a client could OOM the server process with a single multi-gigabyte line — reachable in odek via `odek mcp` from any connected MCP client (2026-08 odek audit, open upstream finding). Server.MaxRequestBytes now caps one inbound message: default DefaultMaxRequestBytes (10 MiB, matching what a typical client accepts for a response), zero selects the default, negative disables (not recommended). An oversized line is answered in-band with -32600 (id null, "exceeds maximum size"), its remainder discarded in constant memory so the stream stays framed, and the dispatch loop keeps serving — per the project rule that bad input never kills the loop. Regression tests: TestRunWithIO_RequestSizeCap (oversized line rejected + next message still served), TestRunWithIO_UnderCapStillServed (default cap admits normal traffic).
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Summary
readMessageaccumulated a line without bound (bufio.ErrBufferFull→ keep appending), so any client could OOM the server process with a single multi-gigabyte line. In odek this is reachable throughodek mcpfrom any connected MCP client (open finding from odek's 2026-08 security audit).Fix:
Server.MaxRequestBytescaps one inbound message.DefaultMaxRequestBytes= 10 MiB (matches what a typical MCP client accepts for a response);0selects the default; negative disables (documented as not recommended).-32600(idnull, "exceeds maximum size") per the project rule that bad input never kills the loop.Testing
TestRunWithIO_RequestSizeCap— oversized line →-32600with null id, then the followinginitializestill succeeds (loop survives, framing intact).TestRunWithIO_UnderCapStillServed— default cap admits normal 4 KiB traffic.go test ./...green (incl. pipe-based integration + subprocess E2E),go vetclean, gofmt clean.