[eersnington]

Fixes #2051.

A writeFile over the 16 MiB frame limit stopped the shared sidecar, which took down every VM on it, and then an uncaught EPIPE crashed the host process.

• The TS client now checks each encoded frame against the max_frame_bytes from the handshake and rejects an oversized one with a typed SidecarFrameTooLarge before writing it, as the Rust client already does. The sidecar and its other VMs stay up.
• A write still in flight when the transport is disposed no longer leaves the stream without an error listener. A late EPIPE is logged to stderr instead of crashing the host.
• resource-limits.mdx documents the frame limit and the per-request ceiling for writeFile after base64.

13 MiB writeFile from VM A, VM B on the same sidecar	main	This PR
VM A	SidecarProcessExited	SidecarFrameTooLarge
VM B	dead	still answers
Host	uncaught EPIPE	no crash

[railway-app]

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[github-actions]

📟 Pip-Boy · 79b018e

📦 Packages · fresh npm install resolve, no lockfile · this PR vs base

package (linux-x64-gnu)	@latest	base	this PR	Δ vs base	packages
@rivet-dev/agentos-core	458.2 MB	325.9 MB	325.9 MB	+3.4 KB (+0.0%)	10 (0)
@rivet-dev/agentos-runtime-core	253.6 MB	253.6 MB	253.6 MB	+3.4 KB (+0.0%)	6 (0)

`@rivet-dev/agentos-core` details

platform	base	this PR	Δ
linux-x64-gnu	325.9 MB	325.9 MB	+3.4 KB (+0.0%)
linux-arm64-gnu	323.1 MB	323.1 MB	+3.4 KB (+0.0%)
darwin-arm64	302.4 MB	302.4 MB	+3.4 KB (+0.0%)
darwin-x64	311.9 MB	311.9 MB	+3.4 KB (+0.0%)
win32-x64	182.3 MB	182.3 MB	+3.4 KB (+0.0%)

Entrypoints (own code, minified; third-party imports excluded)

entrypoint	base	this PR	Δ	imports	exports
.	291.6 KB	292.7 KB	+1.1 KB (+0.4%)	—	+SidecarFrameTooLarge

`@rivet-dev/agentos-runtime-core` details

platform	base	this PR	Δ
linux-x64-gnu	253.6 MB	253.6 MB	+3.4 KB (+0.0%)
linux-arm64-gnu	250.9 MB	250.9 MB	+3.4 KB (+0.0%)
darwin-arm64	230.1 MB	230.2 MB	+3.4 KB (+0.0%)
darwin-x64	239.6 MB	239.6 MB	+3.4 KB (+0.0%)
win32-x64	110.0 MB	110.0 MB	+3.4 KB (+0.0%)

Entrypoints (own code, minified; third-party imports excluded)

entrypoint	base	this PR	Δ	imports	exports
.	248.0 KB	249.1 KB	+1.1 KB (+0.5%)	—	+SidecarFrameTooLarge
./sidecar-client	24.6 KB	25.0 KB	+448 B (+1.8%)	—	+SidecarFrameTooLarge
./sidecar-errors	1.1 KB	1.5 KB	+448 B (+40.8%)	—	+SidecarFrameTooLarge
./sidecar-process	24.6 KB	25.0 KB	+448 B (+1.8%)	—	+SidecarFrameTooLarge

All 6 packages · linux-x64-gnu

package (linux-x64-gnu)	@latest	base	this PR	Δ vs base	packages
@rivet-dev/agentos-core	458.2 MB	325.9 MB	325.9 MB	+3.4 KB (+0.0%)	10 (0)
@rivet-dev/agentos-node-pty	7.6 KB	18.0 KB	18.0 KB	0	1 (0)
@rivet-dev/agentos-posix	253.6 MB	253.6 MB	253.6 MB	+3.4 KB (+0.0%)	7 (0)
@rivet-dev/agentos-runtime-core	253.6 MB	253.6 MB	253.6 MB	+3.4 KB (+0.0%)	6 (0)
@rivet-dev/agentos-sandbox	495.5 MB	363.5 MB	363.5 MB	+3.4 KB (+0.0%)	85 (0)
@rivet-dev/agentos-toolchain	130.8 KB	141.2 KB	141.2 KB	0	2 (0)

🧹 Rust dependencies

Skipped: this PR doesn't change any Rust code or dependencies.

🦀 Binaries

Skipped: this PR doesn't change any Rust code.

⏱ Timing

job	wall time	slowest step
zizmor	8s	checkout · 2s
changes	26s	checkout · 23s
footprint	2m49s	Pack the base · 47s
⏭ native · ${{ matrix.platform }}	—	skipped
⏭ self-test	—	skipped
⏭ hygiene	—	skipped
report	27s	setup-node · 10s

🔭 Full CI trace for this commit

One OpenTelemetry trace of CI and Pip-Boy for 79b018e: every job and step, with the sizes above attached. Run after CI finishes.

pnpm install --frozen-lockfile --filter 'pipboy...'
pnpm --filter pipboy pipboy trace --sha 79b018e389834b47c66a84d48ca3cc33ceb73eec

Add --otlp <url> to send it to any OTLP/HTTP collector.

Agent instruction: From a rivet-dev/agentos checkout, run the commands above, then read the trace file the last command prints. List the slowest jobs and steps and explain where CI time went.