docs(#492/#493): case study — the initialize response that never came - #510
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Self-debugging RCA writeup of the #492 Ruby launch stall: the incident log, why #470's decoder paths were ruled out, mcp-debugger stepping through its own compiled MinimalDapClient (statement breakpoints in dist/, evaluate_expression against pendingRequests, the stack of the event-delivery moment), the fake-rdbg replay with its DAP trace, the rdbg 1.11.0 source analysis (silent `if sock = @sock` drop guard, unsynchronized cleanup_reader) with the seq discriminator for the next live capture, and what #507/#509 changed. Honest about proven vs. hypothesized. Also: troubleshooting gains a section decoding the stage-aware 30s init-timeout message (post-#493), the ruby guide's troubleshooting table maps the new recovery warning to the case study, and the README documentation index links it. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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The full RCA narrative behind PR #522: how a js attach pause_execution could return success forever without pausing anything, why the routing hole a code-reading pass produced was real but not the field mechanism (js-debug's smart-stepper converting user pauses into an endless step chase through internal frames was), the adapterConfig {trace: true} technique that made the adapter narrate its own CDP decisions, and the third bug the fix's e2e caught that interactive repro timing could not reach (pre-adoption dispatch swallowed without a response). Side findings link to the issues they became: #518 (trace parent/child discriminator), #519 (routing logs invisible in the per-session proxy log), #520 (ensureInitialStop's 12s threads poll on js attach). Continues the docs/case-studies series (#510, #516); README links it. Claude-Session: https://claude.ai/code/session_01XtvNu3aNB1nw1URRL5UTgR Co-authored-by: CI Bot <ci@example.com> Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
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Summary
Publishes the self-debugging RCA of the #492 Ruby launch stall as the first entry in a new
docs/case-studies/directory, per the dogfooding session that produced #507 and #509.docs/case-studies/rdbg-initialize-response-stall.mdcovers:MinimalDapClient—statement:breakpoints indist/,evaluate_expressionagainstpendingRequests, the stack of the event-delivery moment — with the actual tool callsDAP_TRACEif sock = @sockdrop guard, the unsynchronizedcleanup_reader, and the seq discriminator (event seq 1 = response skipped; seq 2 = sent-then-lost) that the next live capture will settleCross-links:
docs/troubleshooting.md: new section decoding the stage-aware init-timeout message (post-Proxy-init timeout misattributes the cause: says the adapter 'failed to start' when it connected fine and a DAP request simply never got a response #493) → case studydocs/ruby/README.md: troubleshooting-table row mapping the new recovery warning → case study### AddedentryMerge after #509 (the troubleshooting section describes its message variants).
References #492 #493
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