ZCode/glm-5.3-flash

* c0fc519  (63 seconds)  <Riza Fahmi>   S7: handle Ctrl-C with graceful interruption, partial summary, and exit 130
* abb791a  (15 minutes)  <Riza Fahmi>   S6: report elapsed time and completed-response latency percentiles
* fa5bbd5  (19 minutes)  <Riza Fahmi>   S5: report outcomes by status with separate transport failures and exit codes
* a73effb  (22 minutes)  <Riza Fahmi>   S4: run paced five-second loop with deadline, gap, and cancellation guarantees
* f6897b9  (37 minutes)  <Riza Fahmi>   S3: send one bounded GET with streaming, verification, and no redirects/retries
* 713c714  (49 minutes)  <Riza Fahmi>   S2: validate arguments with stderr errors and exit 2
* 105181e  (56 minutes)  <Riza Fahmi>   S1: launch the cb CLI with help output and Ctrl-C-safe entry point

1. 1High-Effort Efficiency Paradox: 21% Cheaper ($0.87 vs. $1.10) & 36% Faster (71m vs. 111m) Than GLM-5.3-Flash Low3 points▸

   • $0.87 Total Cost & 71m Duration: Running GLM-5.3-Flash with effort: "high" completed all 7 slices with 55/55 passing tests in 71 minutes (05:55–07:06) for $0.87 ($0.8695)—beating GLM-5.3-Flash Low ($1.10, 111m, 42 tests) on both cost and speed while achieving a 93.3% cost reduction vs. GLM-5.3 High ($12.90, 96m).
   • Why Thinking Harder Cost Less: Emitting 2.16x more thinking tokens (91.0k across 190 LLM calls vs. 42.2k across 344 calls in Low) eliminated the multi-turn OTP/GenServer debugging spirals that slowed down the Low run (cutting S3 from 156 calls to 51). Finishing in 154 fewer turns reduced cumulative cached input reads by 25.6% (25.44M vs. 34.21M tokens), saving $0.26 in cache reads at the cost of only $0.02 in extra output tokens.
   • 100% First-Attempt Stream Reliability: Unlike the earlier GLM-5.3-Flash Low session (which suffered 29 TypeError: terminated mid-stream aborts and 58 multi-attempt retries), all 190 LLM calls in this early-morning window succeeded on attempt: 1 with zero stream drops and a 99.15% cache hit rate.
2. 2Single-Turn 10.8-Minute Reasoning Monolith at Line 3 (30,440 Output Tokens, +30.8k Context Jump)3 points▸

   • 647.0 Seconds on a Single Turn At line 3 (05:55:42–06:06:29), before writing any project code, the model spent 10.78 minutes generating 119,493 characters of reasoningText (30,440 output tokens, ~30,117 thinking tokens)—accounting for 33.1% of the entire run's thinking tokens in one API call.
   • Upfront Full-Benchmark Design: Inside that single reasoning trace, the agent evaluated :httpc vs. :mint, designed the module contracts for all 7 slices (CapyBench.CLI, CapyBench.Args, CapyBench.Target, CapyBench.Request, CapyBench.Runner, CapyBench.Summary, and CapyBench.SignalHandler), and planned its test strategy before calling TodoWrite.
   • Permanent +30.8k Context Window Jump: Because ZCode replays assistant reasoning blocks in subsequent requests, line 4's input context jumped from 29,824 to 60,645 tokens (+30,821 uncached tokens), adding ~30k cached tokens to all 186 remaining turns (~5.58M extra cache-read tokens, or ~$0.17 across the session).
3. 3Linting Shortcut: Using 'mix compile --warnings-as-errors' Instead of Credo or mix check2 points▸

   • No Static Analysis Package Added: Although PLAN.md explicitly specifies that "Formatting and compilation do not substitute for linting", the agent did not add credo or mix check to mix.exs.
   • Minimal 6-Line README.md Change: In S1 (line 14), it added only 6 lines to README.md documenting mix compile --warnings-as-errors under a "Lint (compilation warnings are treated as defects, so the build must be clean)" section, relying solely on Elixir 1.20's gradual type checker and compiler warnings for S1 and Release Verification.
4. 4Adopting ':mint' (v1.11.0) in S3: Passing './cb http://rizafahmi.com' Chunked 301 & In-Process HTTPS3 points▸

   • Adding {:mint, "~> 1.7"} Prevented the S5 Chunked-Encoding Bugs Seen in Low & Max Unlike GLM-5.3-Flash Low and GLM-5.3-Flash Max (both of which wrote custom HTTP/1.1 socket parsers that broke on live Transfer-Encoding: chunked responses during ./cb http://rizafahmi.com), GLM-5.3-Flash High added {:mint, "~> 1.7"} (resolving mint 1.11.0 and hpax 1.1.0) in S3 (line 56), enabling it to pass ./cb http://rizafahmi.com cleanly with 41/41 301 responses and 0 failures (the only 7/7 GLM-5.3-Flash run).
   • In-Process Workaround for macOS SSL_CERT_FILE (Lines 55–56) After confirming at line 55 that :public_key.cacerts_get/0 on macOS reads the system Keychain and ignores SSL_CERT_FILE, the agent chose not to read SSL_CERT_FILE in production code (stating in PLAN.md that "the CLI process cannot be pointed at the test CA without adding a configuration surface"). Instead, it tested trusted-CA HTTPS acceptance only in-process via CapyBench.Request.run/2 with injected cacerts while testing untrusted/mismatched HTTPS rejection through the built ./cb CLI.
   • OTP 28 :ssl.handshake/3 {:dtls_upgrade, :notsup} Socket-Ownership Trap (Lines 78–92) In test/support/test_server.ex, spawning a child process to run :ssl.handshake/3 on a socket accepted by the parent accept_loop failed with {:error, {:dtls_upgrade, :notsup}} because OTP's internal TCP-to-TLS upgrade requires the caller to be the socket's controlling process. After 14 turns of isolation, transferring ownership in the acceptor via :gen_tcp.controlling_process(tcp_socket, pid) before sending :go fixed the handshake (line 91).
5. 522-Turn S2 Bisect of a POSIX 'if wait' Exit-Status Bug & Committed 2.89 MB erl_crash.dump2 points▸

   • POSIX 'if'-Without-'else' Resetting $? to 0 (Lines 29–50, ~6m) In S1 (line 11), the ./cb wrapper used if wait "$child"; then status=0; break; fi; status=$?. When S2 tested invalid CLI arguments (where cb.escript halted with code 2), ./cb exited 0 because in POSIX sh (bash 3.2), an if construct without an else branch evaluates to exit status 0 when the condition fails. The agent spent 22 turns bisecting trap, set -u, /bin/sh, and while loops across /tmp/w1.sh–/tmp/wS10.sh before moving status=$? inside an else branch at line 50.
   • 2.89 MB erl_crash.dump Committed in S2 (713c714) At line 29, piping mix test test/capy_bench/cli_test.exs 2>&1 | head -50 closed stdout early while the BEAM was still writing output, dumping a 2,891,346-byte (93,612-line) erl_crash.dump to the project root. Because .gitignore only ignored /_build/, /deps/, and /cb.escript, switching from explicit file staging in S1 to git add -A at line 54 permanently committed erl_crash.dump in S2.
6. 6Release Verification Caught a Raw Failure-Tuple Bug & a zsh 'MULTIOS' Redirection Quirk2 points▸

   • Unwrapping {:failure, reason} in Stderr Diagnostics (Lines 180–181) Running the built ./cb binary against a connection-refusing port (http://127.0.0.1:1/) during Release Verification exposed that CapyBench.CLI.describe/1 printed raw Elixir tuples ({:failure, {:connect, %Mint.TransportError{reason: :econnrefused}}}) to stderr because it lacked a clause unwrapping {:failure, reason}. Adding defp describe({:failure, reason}), do: describe(reason) at line 181 produced clean "cb: 50 transport failure(s): connect: connection refused" diagnostics.
   • Diagnosing zsh MULTIOS Teeing (Lines 182–184) When verifying stream separation via ./cb http://127.0.0.1:1/ 2>&1 >/dev/null | head -3, the stdout summary unexpectedly appeared in the pipe. At line 184, the agent realized ZCode's Bash tool executes under zsh, where MULTIOS tees stdout to both /dev/null and the pipe when 2>&1 precedes >/dev/null, and confirmed clean stream separation using explicit file redirections.
7. 7ZCode File-State Guard Friction (10 Edit/Write Errors) & 7 Clean Slice Commits2 points▸

   • 10 File-State Guard Rejections & 17 Inline Script Edits Running mix format via Bash updated file mtimes on disk and caused 8 Edit calls (lines 70x3, 83, 97x2, 114x2) and 1 Write call (line 25) to fail with "File has been modified since read", plus 1 Write error at line 11 ("File has not been read yet" on mix.exs). To avoid extra Read turns, the agent executed 13 inline python3 - <<'EOF' patches and 4 sed -i edits.
   • 7 Clean Slice Commits (Release Verification Bundled into S7) Unlike the 8-commit GLM-5.3 High and GLM-5.3-Flash Low runs, the agent ran Release Verification (lines 180–186) before creating the S7 commit at line 187 (c0fc519), producing 7 single-line commits (S1–S7, with S5 amended at line 140 to include PLAN.md) and zero hallucinated Co-Authored-By trailers.