The Go daemon is what actually runs on 30+ fleet hosts; until now it had none of the
wire-protocol work that went into the Python reference (gateway/sicd) — which is why sic
still ate a bare -- and silently wrote zero-byte files in production. This ports it: preamble
+ nested netstring peeling (one layer per hop), payload -> child stdin then remaining stdin
pumped through (the zero-byte-file fix), bare -- survives as opaque payload, malformed frame
-> exit 1, no deadlock above the 64 KiB pipe buffer, short writes looped, EPIPE handled,
signal-killed child -> exit 128+WTERMSIG. Built by the bullpen room (@testdesigner -> @godev
-> @reviewer), the first Go work the room could grade.
CHECKPOINT commit, green but NOT final: 28/28 Go, 24/24 Python, go vet clean. @reviewer's
third pass found four divergences from the reference that a fix round is about to address —
recorded here so the checkpoint is honest:
1. (must-fix, security) the Go netstring parser accepts frames the reference REJECTS and
executes them: trailing data after the comma, a +-prefixed length, and no 1<<24 cap. A
malformed frame that fails closed on a Python hop currently runs on a Go hop. The Python
suite does not pin these either — both suites need the malformed cases added.
2. (must-fix) the read-error path os.Exit(1)s without reaping the child, leaving it detached
and still writing to inherited stdout after sicd reports its status.
3. (test) an EPIPE test's premise is wrong in Go (LookPath fails at Start, so the payload
write never happens); the path is really covered by the signal test.
4. (test) the pty EIO test is synchronized only by a 300 ms sleep.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
CPython sets SIGPIPE to SIG_IGN so EPIPE surfaces as BrokenPipeError.
A Go port must replicate this explicitly or the EPIPE path silently
becomes a SIGPIPE death.
24/24 green.
write_all() loops until the full buffer is transferred — os.write's return value was
ignored at the payload write and in the pump loop, so a short write silently truncated
the stream. EPIPE at the payload write (child already dead) now reaps the child and
inherits its status instead of dying with a BrokenPipeError traceback; EPIPE in the pump
loop falls through to the same waitpid, which is standard `cmd | head` semantics.
Tests use deterministic fault injection rather than racing signals: a fork wrapper that
waits with waitid(WNOWAIT) so the child is provably dead but still reapable before the
parent writes, and an os.write cap of 7 bytes per call as the stand-in for a
signal-interrupted partial write.
Reviewed three times. Known gaps, tracked, NOT fixed here: signal-killed children still
collapse to exit 1 (no 128+WTERMSIG), and the pump loop's `except OSError: pass` is
broader than it should be.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
- Pump loop after fork: parent streams stdin to child through pipe
- netstring: enforce .isdigit() on length field
- netstring: require exact consumption (no trailing data)
- argv split: use .split space not .split
- Non-ASCII command: fail loudly
- Child exec failure: os._exit(1)
17/17 pytest green
- Read preamble: magic byte \x00 + 4-byte BE length + netstring
- Split netstring at first NUL: command\0<payload>
- Exec command with payload + trailing stdin forwarded
- Nested payloads are netstrings for the next hop (one layer peeled per sicd)
- Bare -- survives as opaque data
- Malformed input: exit 1 with stderr diagnostic
- 14/14 pytest green
Agents (esp. small models) keep calling `fetch_url https://...` positionally
instead of `fetch_url url="https://..."`. The key=value parser turned a bare
URL into {"<url>":""} with no `url` key, so the server rejected it with the
misleading "url must start with http:// or https://". Now a lone http(s)://
positional is mapped to url=, killing this recurring pi-agent failure. Explicit
key=value and raw-JSON forms are unchanged.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EWpfhDgYNA21tETDP9ueBE
lmcp-tool drives a host's lmcp (MCP) tools over a stateless tools/call via sic —
list for discovery, key=value args so a model never embeds JSON in a shell (apostrophe-safe).
sicwrite/sicedit pass file content as argv since sicd consumes stdin for the frame.
References the lmcp server project: git.reauktion.de/marfrit/lmcp
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EWpfhDgYNA21tETDP9ueBE
The quotesu setup notes exposed internal host details and aren't useful to
readers, so remove the directory. The quoting-hell demo now requires the
target host as an argument (any host running sicd) instead of defaulting to
an internal name, and its labels say sic rather than the old rs. Example
hostnames in the README/SKILL/main.go are now the neutral placeholder host1.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EWpfhDgYNA21tETDP9ueBE
Client (sic) frames argv as netstrings and pipes it over ssh to a daemon
(sicd) that execvp's it, so no shell re-parses the arguments. exec mode by
default; opt-in sh mode for pipes/redirects/globs. Go client + daemon, Python
reference daemon, design doc, quoting-hell demo, and foreground/background
agent skills.
Renamed from the climcp prototype.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EWpfhDgYNA21tETDP9ueBE
Claude (noether)