From 8f28c317fb310452ba1acbf46c87a3c9e8050512 Mon Sep 17 00:00:00 2001
From: chipfighter <92256151+chipfighter@users.noreply.github.com>
Date: Sat, 1 Aug 2026 12:32:47 +0900
Subject: [PATCH] feat(hooks): let the primer be disabled on its own

The primer is fixed cost paid on every session, and nothing here has ever
measured what it buys. Deleting it because another project deleted theirs would
be a guess; keeping it because it feels useful is the same guess wearing the
other hat. CD_PRIMER=0 makes the question answerable by changing that one
variable.

Counting and guide seeding run before the opt-out, so switching the primer off
leaves every other side effect intact and keeps an A/B honest.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
---
 README.md                                     | 11 ++++++++
 README.zh-CN.md                               | 10 +++++++
 .../hooks/session-start-skills                |  8 ++++++
 tests/test-hooks.sh                           | 27 +++++++++++++++++++
 4 files changed, 56 insertions(+)

diff --git a/README.md b/README.md
index 48ba13a..5e05b51 100644
--- a/README.md
+++ b/README.md
@@ -160,6 +160,17 @@ Disable counting:
 CD_USAGE_ENABLED=0
 ```
 
+Disable the primer by itself, leaving counting and guide seeding in place:
+
+```bash
+CD_PRIMER=0
+```
+
+The primer is fixed cost paid on every session, and whether it earns that cost
+is a question about your workload rather than a claim this project can settle
+for you. This switch is what makes it answerable: run the same tasks with it on
+and off, and compare.
+
 ## Project guide seeding
 
 On the first session inside a Git repository, the plugin creates an empty guide
diff --git a/README.zh-CN.md b/README.zh-CN.md
index d45dc12..2eb168a 100644
--- a/README.zh-CN.md
+++ b/README.zh-CN.md
@@ -144,6 +144,16 @@ bash plugins/coding-discipline/hooks/skills-count.sh
 CD_USAGE_ENABLED=0
 ```
 
+只关闭纪律总纲，保留计数和引导文档生成：
+
+```bash
+CD_PRIMER=0
+```
+
+总纲是每个 session 都要付的固定开销。它值不值这个开销，取决于你自己的工作
+负载，不是本项目单方面能替你下结论的事。这个开关的意义就在于让它可被回答：
+同样一批任务，开和关各跑一遍，比较结果。
+
 ## 自动生成项目引导文档
 
 第一次在 Git 仓库中开启 session 时，如果目标文件不存在，插件会创建一份
diff --git a/plugins/coding-discipline/hooks/session-start-skills b/plugins/coding-discipline/hooks/session-start-skills
index ea7af2f..fe09384 100755
--- a/plugins/coding-discipline/hooks/session-start-skills
+++ b/plugins/coding-discipline/hooks/session-start-skills
@@ -66,6 +66,14 @@ seed_agent_doc() {
 }
 seed_agent_doc || true
 
+# The primer is the one piece worth isolating: it is fixed cost paid on every
+# session, and whether it earns that cost can only be measured by turning it off
+# on its own. Counting and seeding already ran above, so this changes nothing but
+# the injected text.
+case "${CD_PRIMER:-1}" in
+  0|false|False|FALSE|no|No|NO|off|Off|OFF) exit 0 ;;
+esac
+
 # Cursor uses additional_context; Copilot/SDK uses top-level additionalContext;
 # Claude Code, Codex, and the default path use
 # hookSpecificOutput.additionalContext.
diff --git a/tests/test-hooks.sh b/tests/test-hooks.sh
index ea146b6..05217db 100755
--- a/tests/test-hooks.sh
+++ b/tests/test-hooks.sh
@@ -174,4 +174,31 @@ case "$output" in
   *'Skill tool'*) fail 'a non-primary host received Claude Code wording' ;;
 esac
 
+# The primer can be switched off on its own. Measuring what those characters buy
+# means changing that one variable and nothing else, so usage counting and guide
+# seeding have to survive the opt-out.
+repo_primer_off="${TMP_ROOT}/repo-primer-off"
+make_repo "$repo_primer_off"
+output="$({
+  cd "$repo_primer_off"
+  CD_PRIMER=0 CD_USAGE_LOG="${TMP_ROOT}/usage-primer-off.jsonl" "$HOOK" claude-code
+})"
+[ -z "$output" ] || fail 'CD_PRIMER=0 still emitted a primer payload'
+[ -f "${repo_primer_off}/CLAUDE.md" ] || fail 'CD_PRIMER=0 also suppressed guide seeding'
+grep -q '"platform":"claude-code"' "${TMP_ROOT}/usage-primer-off.jsonl" \
+  || fail 'CD_PRIMER=0 also suppressed usage counting'
+
+# Leaving it unset keeps the current behavior.
+repo_primer_on="${TMP_ROOT}/repo-primer-on"
+make_repo "$repo_primer_on"
+output="$({
+  cd "$repo_primer_on"
+  CD_USAGE_ENABLED=0 "$HOOK" claude-code
+})"
+printf '%s\n' "$output" | assert_json_output
+case "$output" in
+  *'Skill discipline'*) ;;
+  *) fail 'the default path stopped injecting the primer' ;;
+esac
+
 printf 'hook behavior tests passed\n'