diff --git a/a3p-integration/README.md b/a3p-integration/README.md
index 5318bbba750..a9e6ff031ea 100644
--- a/a3p-integration/README.md
+++ b/a3p-integration/README.md
@@ -153,12 +153,12 @@ make -C ../packages/deployment docker-build-sdk
 
 In a3p-integration, many core-eval proposals' `submission` content has to be
 generated from the local `agoric-sdk`, and must be rebuilt every time there is a
-change. The `scripts/build-all-submissions.sh` script contains commands to
-generate the core-eval content and move it to the expected proposal package's
-submission directory. The generation is executed as part of `a3p-integration`'s
-`build:submissions` step. Each proposal that requires such a build step should
-add an entry to the `sdk-generate` array in the `agoricProposal` section of
-`package.json`.
+change. This package's package.json `build:submissions` script runs
+`scripts/build-all-submissions.sh` to generate that content and move it into
+submission subdirectories under the corresponding [proposal
+directories](#package-layering). Each proposal that requires such a build step
+should have a corresponding entry in the `sdk-generate` array of its proposal
+directory's package.json `agoricProposal` section.
 
 Submissions that don't need to pass in options or generate references to source
 bundles can be written directly in a `foo-submission` subdirectory of the
@@ -172,15 +172,17 @@ provided, it should be written as two parts: a core eval (in one of the
 `.../proposals` directories) and a builder for it (under `.../builders/scripts`).
 
 The `build-all-submissions.sh` script reads instructions from
-`agoricProposal.sdk-generate` in `package.json`. That field contains a list of
-strings, each of which describes a single submission. If there is only one
-submission, it can use the default directory name `submission` by specifying
-only the name of the script file in `builders/scripts/vars`:
+`agoricProposal.sdk-generate` in package.json. That field contains a list of
+strings, each of which describes a single submission as a list of
+space-separated fields. If there is only one submission, it can use the default
+directory name `submission` by specifying just one field, containing the path of
+a builder script file relative to
+[packages/builders/scripts](../packages/builders/scripts):
 ```json
 "sdk-generate": ["test-localchain"],
 ```
-If there are multiple submissions, each entry has to specify the script name and
-a distinct directory name.
+If there are multiple submissions, each entry has to specify a distinct
+directory name in the second field:
 ```json
 "sdk-generate": [
   "probe-zcf-bundle probe-submission",
@@ -188,8 +190,7 @@ a distinct directory name.
   "add-auction newAuction-submission"
 ],
 ```
-A third argument can be used to provide additional parameters to the
-build script.
+Any remaining fields provide additional arguments to the build script:
 ```json
 "sdk-generate": [
   "inter-protocol/updatePriceFeeds.js submission/main main",
diff --git a/a3p-integration/debug-current.sh b/a3p-integration/debug-current.sh
index 93a15440a4c..6fabda024e6 100755
--- a/a3p-integration/debug-current.sh
+++ b/a3p-integration/debug-current.sh
@@ -1,8 +1,12 @@
-#!/bin/sh
+#!/bin/bash
+set -ueo pipefail
 
 # Convenience script to debug the current proposal being worked on.
 
-scripts/build-submission.sh proposals/z:acceptance testing/start-valueVow.js start-valueVow
-scripts/build-submission.sh proposals/z:acceptance testing/restart-valueVow.js restart-valueVow
+(
+  cd 'proposals/z:acceptance'
+  ../../scripts/build-submission.sh testing/start-valueVow.js start-valueVow
+  ../../scripts/build-submission.sh testing/restart-valueVow.js restart-valueVow
+)
 
 yarn test -m acceptance --debug
diff --git a/a3p-integration/scripts/build-all-submissions.sh b/a3p-integration/scripts/build-all-submissions.sh
index ad97a44d388..31ffc53dfe0 100755
--- a/a3p-integration/scripts/build-all-submissions.sh
+++ b/a3p-integration/scripts/build-all-submissions.sh
@@ -1,17 +1,24 @@
 #!/bin/bash
 set -ueo pipefail
 
-# cd prints its target, so without the redirect, we get two copies
-SCRIPT_DIR=$(cd ${0%/*} > /dev/null && pwd -P)
+# Look in the "proposals" subdirectory of the working directory for
+# "$char:$name" subdirectories (cf. ../README.md#package-layering), and for each
+# one, extract from its package.json "agoricProposal" section a list of
+# "sdk-generate" entries corresponding to core-eval submission content that must
+# be generated (cf ../README.md#generating-core-eval-submissions) and then use
+# ./build-submission.sh to do so.
+
+SCRIPT_DIR=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &> /dev/null && pwd)
 
 IFS=$'\n'
 
 for proposal in ./proposals/?:*; do
+  echo >&2 "Building $proposal ..."
   cd $proposal
-  # build submission if proposal specifies an sdk-generate
   while read -r line; do
     IFS=' ' parts=($line)
-    $SCRIPT_DIR/build-submission.sh $proposal ${parts[@]}
+    "$SCRIPT_DIR"/build-submission.sh ${parts[@]}
   done < <(jq -r '.agoricProposal["sdk-generate"][]?' < package.json)
   cd -
+  echo >&2 "Built $proposal"
 done
diff --git a/a3p-integration/scripts/build-submission.sh b/a3p-integration/scripts/build-submission.sh
index 3470c24cf52..757c7641907 100755
--- a/a3p-integration/scripts/build-submission.sh
+++ b/a3p-integration/scripts/build-submission.sh
@@ -1,23 +1,34 @@
 #!/bin/bash
 set -ueo pipefail
 
-sdkroot=$(git rev-parse --show-toplevel)
+# Usage: $0 <builder script> [submission directory name] [builder script arg]...
+# Run the specified builder script from packages/builders/scripts and move the
+# output into the specified submission directory (defaulting to "submission")
+# relative to the working directory.
+# Must be run from inside agoric-sdk.
 
-cd "$sdkroot"
+builderScript=$1
+shift
+submissionDir=${1:-submission}
+shift || true
 
-a3pProposalDir=$1
-builderScript=$2
-submissionDirName=${3:-submission}
-submissionDir="./a3p-integration/$a3pProposalDir/$submissionDirName"
-extraParams=${4:-}
+# Run the builder script in a subshell at agoric-sdk.
+sdkroot=$(git rev-parse --show-toplevel)
+(
+  cd "$sdkroot"
+  yarn agoric run "packages/builders/scripts/$builderScript" "$@"
+)
 
-yarn agoric run "packages/builders/scripts/$builderScript" $extraParams
+# Create and populate the submission directory.
 mkdir -p "$submissionDir"
+echo >&2 "Populating $(basename -- "$(pwd -P)")/$submissionDir ..."
+ls "$sdkroot"/*-plan.json | while read plan; do
+  # Copy from the bundle cache.
+  cp $(grep -oh '/.*b1-.*.json' "$plan") "$submissionDir"
+
+  # Move from the root directory.
+  prefix=${plan%-plan.json}
+  mv "$prefix"* "$submissionDir"
 
-plans=*-plan.json
-for plan in $plans; do
-  base=${plan%-plan.json}
-  cp $(grep -oh '/.*b1-.*.json' "$base"-plan.json) "$submissionDir"
-  mv "$base"* "$submissionDir"
   ls -oS "$submissionDir"
 done