Add Claude Code on the web SessionStart hook (Rust + Elixir)#155
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Cloud sessions ship cargo but not Erlang/Elixir, which the elixir-orchestration layer needs. Adds a cloud-only SessionStart hook that: - installs Erlang (apt, OTP 25) + Elixir 1.17 (GitHub precompiled, satisfies elixir-orchestration's `elixir: "~> 1.17"`), idempotently; - warms the Rust workspace with `cargo fetch` (the ~20-crate build compiles on first use — too heavy to run synchronously every session); - best-effort `mix deps.get` for the Elixir deps. Every step is best-effort and cloud-only (CLAUDE_CODE_REMOTE) so it never aborts session startup. Network note: `mix deps.get` needs Hex registry access (repo.hex.pm / builds.hex.pm); on a restrictive "Trusted" allowlist those are blocked (403) and skipped cleanly, on "Full" access they complete. cargo works on Trusted (crates.io is allowlisted). REUSE.toml: cover .claude/** under MPL-2.0 (settings.json carries no inline SPDX header; the hook script has one). Validated in a cloud session: hook exits 0, installs Erlang+Elixir (mix 1.17.3) and runs cargo fetch; local-skip is a no-op; the Hex-blocked mix step degrades gracefully. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_017nyxs8RgqZa72PzrTu3L75
hyperpolymath
marked this pull request as ready for review
June 21, 2026 14:06
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What
Adds a cloud-only
SessionStarthook so Claude Code on the web sessions start with VeriSimDB's toolchain ready. Cloud images shipcargobut not Erlang/Elixir (whichelixir-orchestrationneeds), so the hook installs them and warms the workspace.Changes (
.claude/).claude/hooks/session-start.sh— cloud-only (CLAUDE_CODE_REMOTE), idempotent, best-effort:elixir-orchestration'selixir: "~> 1.17".cargo fetch(the ~20-crate workspace compiles on first use — too heavy to build synchronously every session).mix deps.getfor the Elixir deps.Plus
.claude/settings.json(registers the hook onstartup|resume) and aREUSE.tomlannotation covering.claude/**.Scope notes
CLAUDE.mdstill lists ReScript as allowed — worth reconciling.)Network caveat (important)
mix deps.getneeds the Hex registry (repo.hex.pm/builds.hex.pm). On a restrictive Trusted network allowlist those are blocked (HTTP 403) and skipped cleanly; on Full network access they complete.cargoworks on Trusted (crates.io is allowlisted). For faster startup, the install step is a good candidate to move to a cached Setup Script (environment config).Validation (in a cloud session)
mix 1.17.3) and runscargo fetchCLAUDE_CODE_REMOTEis unsetmix deps.get403s on this session's Trusted network (degrades gracefully, as designed) — validates fully only on Full networkNote
Synchronous hook: it guarantees the toolchain is ready before the session starts, at the cost of install time on first run. Can switch to async, or move installs to a cached Setup Script, if preferred.
🤖 Generated with Claude Code
https://claude.ai/code/session_017nyxs8RgqZa72PzrTu3L75
Generated by Claude Code