feat: implement issue #1105 — [Phase 2] Rewire the security-audit + single-review tier prompts to consume pre-fed context

.github/workflows/lint.yml

@@ -98,6 +98,7 @@ jobs:
             tests/test_safety_checks.bats \
             tests/test_safety_checks_triage_inline.bats \
             tests/test_prefetch_context.bats \
+            tests/test_prefetch_prompt_rewire.bats \
             tests/test_engine_unavailable_notice.bats \
             tests/test_batch_skip_reporting.bats \
             tests/test_review_one_pr_ci_pending.bats \

prompts/cascade-action.md

@@ -9,6 +9,12 @@ security audit) has produced a verdict in `$FINAL_RESULT`. Your job is to:
 
 The review will be posted by the bash script, not by this prompt.
 
+> **Pre-fed PR context (epic #1101):** This step synthesizes the already-resolved
+> verdict in `$FINAL_RESULT` (plus prior-tier context) into the posting body. It
+> **does not fetch** the PR diff or metadata — so it needs no pre-fed-context
+> rewire and is explicitly **out of scope** for the Story-5 (#1105) audit/single
+> prompt changes.
+
 ## Inputs (environment variables)
 
 - `$FINAL_RESULT` — path to verdict JSON from the resolving tier

prompts/security-audit.md

@@ -25,12 +25,44 @@ reviewer, called only for PRs with real concerns.
 
 **FORBIDDEN**: enumeration commands, actions on other PRs.
 
+## Pre-fed PR context
+
+When the shared context prefetch is enabled (epic #1101, Story 2), the
+orchestrator fetches the FULL diff and a superset `gh pr view` metadata JSON
+ONCE and persists them to SHA-bound files, exporting their paths:
+
+- `$PR_CONTEXT_METADATA_FILE` — the superset metadata JSON, stamped with a
+  top-level `.pr_head_sha` field (read it with
+  `jq -r '.pr_head_sha' "$PR_CONTEXT_METADATA_FILE"`).
+- `$PR_CONTEXT_DIFF_FILE` — the full diff, whose first line is
+  `# PR_HEAD_SHA: <sha>`.
+
+**If** both variables are set, the files exist, **and** their stamp matches
+`$PR_HEAD_SHA`, then read the pre-fed metadata and diff from these files
+**instead of** running the `gh pr view` / `gh pr diff` in steps 2–3 below — it
+is the same context, already fetched, so do not re-fetch it.
+
+**Otherwise** (the prefetch flag is off, the variables are unset, a file is
+missing, or the stamp does NOT match `$PR_HEAD_SHA` — meaning the PR moved and
+the pre-fed copy is stale), fall back to running `gh pr view` / `gh pr diff`
+exactly as written in steps 2–3. Behavior is byte-identical when the prefetch
+is off.
+
+This covers only the primary metadata + diff (steps 2–3). Everything else —
+the linked-issue fetch (step 4), the org-standards fetch via `gh api`
+(step 5), and (when enabled) LSP finding-verification — stays dynamic; keep
+using `gh`, `gh api`, and the MCP/LSP tools for those.
+
 ## Steps
 
 1. Read `$TRIAGE_RESULT` (triage signals) and the deep review verdict at
    `$DEEP_RESULT` (its findings, risk, and reasoning).
 2. `gh pr view "$PR_URL" --json number,title,body,author,isDraft,baseRefName,headRefName,headRefOid,url,headRepository,headRepositoryOwner,labels,reviewDecision,mergeable,mergeStateStatus,statusCheckRollup,reviewRequests,reviews,comments,commits,closingIssuesReferences,additions,deletions,changedFiles,files`
-3. `gh pr diff "$PR_URL"` — read the diff. Focus on the areas the deep review flagged.
+   — unless the metadata was pre-fed (see **Pre-fed PR context**), in which case
+   read it from `$PR_CONTEXT_METADATA_FILE` instead of running this command.
+3. `gh pr diff "$PR_URL"` — read the diff. Focus on the areas the deep review
+   flagged. Unless the diff was pre-fed (see **Pre-fed PR context**), in which
+   case read it from `$PR_CONTEXT_DIFF_FILE` instead of running this command.
 4. Fetch linked issues if any.
 5. Read any CONTRIBUTING.md, AGENTS.md, CODEOWNERS in the repo to check
    standards compliance (fetch via `gh api`).

prompts/single-review.md

@@ -33,12 +33,46 @@ You review **exactly one pull request**: `$PR_URL`. Nothing else.
 - `gh search prs`, `gh pr list`, `gh pr status`, or any enumeration command.
 - Any action on any PR other than `$PR_URL`.
 
+## Pre-fed PR context
+
+When the shared context prefetch is enabled (epic #1101, Story 2), the
+orchestrator fetches the FULL diff and a superset `gh pr view` metadata JSON
+ONCE and persists them to SHA-bound files, exporting their paths:
+
+- `$PR_CONTEXT_METADATA_FILE` — the superset metadata JSON, stamped with a
+  top-level `.pr_head_sha` field (read it with
+  `jq -r '.pr_head_sha' "$PR_CONTEXT_METADATA_FILE"`).
+- `$PR_CONTEXT_DIFF_FILE` — the full diff, whose first line is
+  `# PR_HEAD_SHA: <sha>`.
+
+**If** both variables are set, the files exist, **and** their stamp matches
+`$PR_HEAD_SHA`, then read the pre-fed metadata and diff from these files
+**instead of** running the `gh pr view` / `gh pr diff` in steps 1–2 below — it
+is the same context, already fetched, so do not re-fetch it. Still apply the
+step-1 `isDraft` and `headRefOid == $PR_HEAD_SHA` skip checks against the
+pre-fed metadata.
+
+**Otherwise** (the prefetch flag is off, the variables are unset, a file is
+missing, or the stamp does NOT match `$PR_HEAD_SHA` — meaning the PR moved and
+the pre-fed copy is stale), fall back to running `gh pr view` / `gh pr diff`
+exactly as written in steps 1–2. Behavior is byte-identical when the prefetch
+is off.
+
+This covers only the primary metadata + diff (steps 1–2). Everything else —
+the incremental-mode `gh api .../compare` diff-since-prior-review (step 2), the
+`run_secret_scanning` MCP scan (step 3), and the linked-issue fetch (step 4) —
+stays dynamic; keep using `gh`, `gh api`, and the MCP tools for those.
+
 ## Context-gathering
 
 1. `gh pr view "$PR_URL" --json number,title,body,author,isDraft,baseRefName,headRefName,headRefOid,url,headRepository,headRepositoryOwner,labels,reviewDecision,mergeable,mergeStateStatus,statusCheckRollup,reviewRequests,reviews,comments,commits,closingIssuesReferences,additions,deletions,changedFiles,files`
+   — unless the metadata was pre-fed (see **Pre-fed PR context**), in which case
+   read it from `$PR_CONTEXT_METADATA_FILE` instead of running this command.
    - If `isDraft` → skip. Write the skip verdict to `$OUTPUT_FILE` using `jq` (e.g., `jq -n --arg pr "$PR_URL" '{pr: $pr, decision: "skip", reason: "draft"}' > "$OUTPUT_FILE"`) and exit.
    - Verify `headRefOid == $PR_HEAD_SHA`. If not → write the skip verdict to `$OUTPUT_FILE` using `jq` (e.g., `jq -n --arg pr "$PR_URL" '{pr: $pr, decision: "skip", reason: "head-sha-changed"}' > "$OUTPUT_FILE"`) and exit.
-2. `gh pr diff "$PR_URL"` — read the diff.
+2. `gh pr diff "$PR_URL"` — read the diff. Unless the diff was pre-fed (see
+   **Pre-fed PR context**), in which case read it from `$PR_CONTEXT_DIFF_FILE`
+   instead of running this command.
    - **Incremental mode**: also get the diff since the prior review. Derive
      `<owner>` and `<repo>` from the `headRepository` field in the PR metadata
      (i.e., `headRepository.owner.login` and `headRepository.name`):

tests/test_prefetch_prompt_rewire.bats

@@ -0,0 +1,140 @@
+#!/usr/bin/env bats
+# Structural guard for the tier-3 audit + single-review pre-fed-context rewire
+# (epic #1101, Story 5 / #1105).
+#
+# Story 2 (#1103) persists the FULL diff + superset metadata ONCE to SHA-bound
+# files exposed as PR_CONTEXT_DIFF_FILE / PR_CONTEXT_METADATA_FILE (gated
+# DEFAULT-OFF behind PREFETCH_CONTEXT_ENABLED). This story rewires
+# prompts/security-audit.md and prompts/single-review.md to CONSUME those files
+# instead of re-running `gh pr view` / `gh pr diff` when they are present and
+# fresh, while staying byte-identical when the flag is off (files absent), and
+# keeping their dynamic `gh api` / MCP / LSP steps intact.
+#
+# These checks are deterministic and offline — the live single/audit smoke run
+# (AC #5) needs the real cascade engine. They guard against the pre-fed section
+# being silently removed or hollowed out by a future edit/template sync, the same
+# silent-revert regression class the repo defends against elsewhere (#655, #823).
+
+setup() {
+  ROOT="$(cd "$BATS_TEST_DIRNAME/.." && pwd)"
+  AUDIT="$ROOT/prompts/security-audit.md"
+  SINGLE="$ROOT/prompts/single-review.md"
+  ACTION="$ROOT/prompts/cascade-action.md"
+}
+
+# Extract the body of the "Pre-fed PR context" section (from its heading up to
+# the next `## ` heading) so the pre-fed-specific assertions cannot accidentally
+# match text elsewhere in the prompt.
+_prefed_section() {
+  [ -f "${1:-}" ] || return 1
+  awk '
+    /^##[[:space:]]+Pre-fed PR context/ { insec=1; next }
+    insec && /^##[[:space:]]/           { insec=0 }
+    insec                               { print }
+  ' "$1"
+}
+
+# Extract the body of an arbitrary named section (heading word(s) passed as $1,
+# file as $2) so fallback-step assertions cannot accidentally match prose in the
+# Pre-fed PR context section that also mentions `gh pr view` / `gh pr diff`.
+_section() {
+  local heading="$1" file="$2"
+  [ -f "${file:-}" ] || return 1
+  awk -v pat="^##[[:space:]]+${heading}" '
+    $0 ~ pat              { insec=1; next }
+    insec && /^##[[:space:]]/ { insec=0 }
+    insec                 { print }
+  ' "$file"
+}
+
+# --- security-audit.md ------------------------------------------------------
+
+@test "audit prompt has a Pre-fed PR context section" {
+  grep -Eq '^##[[:space:]]+Pre-fed PR context' "$AUDIT"
+}
+
+@test "audit pre-fed section references both context env vars" {
+  section="$(_prefed_section "$AUDIT")"
+  grep -q 'PR_CONTEXT_METADATA_FILE' <<<"$section"
+  grep -q 'PR_CONTEXT_DIFF_FILE' <<<"$section"
+}
+
+@test "audit pre-fed section says to read the files INSTEAD of gh, else fall back" {
+  # The 'if set, read instead of gh; else run gh as before' contract keeps the
+  # flag-off path byte-identical.
+  section="$(_prefed_section "$AUDIT")"
+  grep -Eiq 'instead of' <<<"$section"
+  grep -Eiq 'fall back|else|otherwise' <<<"$section"
+}
+
+@test "audit pre-fed section verifies the PR_HEAD_SHA freshness stamp" {
+  section="$(_prefed_section "$AUDIT")"
+  grep -q 'PR_HEAD_SHA' <<<"$section"
+  grep -Eiq 'pr_head_sha|stamp|match|fresh' <<<"$section"
+}
+
+@test "audit prompt retains its dynamic gh api standards fetch" {
+  # The org-standards fetch (CONTRIBUTING/AGENTS/CODEOWNERS via gh api) is
+  # DYNAMIC and must survive the rewire — it is not part of the pre-fed context.
+  grep -q 'gh api' "$AUDIT"
+}
+
+@test "audit prompt still keeps gh pr view / gh pr diff as the fallback fetch" {
+  steps="$(_section 'Steps' "$AUDIT")"
+  grep -q 'gh pr view' <<<"$steps"
+  grep -q 'gh pr diff' <<<"$steps"
+}
+
+# --- single-review.md -------------------------------------------------------
+
+@test "single-review prompt has a Pre-fed PR context section" {
+  grep -Eq '^##[[:space:]]+Pre-fed PR context' "$SINGLE"
+}
+
+@test "single-review pre-fed section references both context env vars" {
+  section="$(_prefed_section "$SINGLE")"
+  grep -q 'PR_CONTEXT_METADATA_FILE' <<<"$section"
+  grep -q 'PR_CONTEXT_DIFF_FILE' <<<"$section"
+}
+
+@test "single-review pre-fed section says to read the files INSTEAD of gh, else fall back" {
+  section="$(_prefed_section "$SINGLE")"
+  grep -Eiq 'instead of' <<<"$section"
+  grep -Eiq 'fall back|else|otherwise' <<<"$section"
+}
+
+@test "single-review pre-fed section verifies the PR_HEAD_SHA freshness stamp" {
+  section="$(_prefed_section "$SINGLE")"
+  grep -q 'PR_HEAD_SHA' <<<"$section"
+  grep -Eiq 'pr_head_sha|stamp|match|fresh' <<<"$section"
+}
+
+@test "single-review prompt keeps its dynamic MCP secret scan + incremental compare" {
+  # These are beyond the pre-fed metadata/diff and must remain dynamic.
+  grep -q 'run_secret_scanning' "$SINGLE"
+  grep -q 'compare/' "$SINGLE"
+}
+
+@test "single-review prompt still keeps gh pr view / gh pr diff as the fallback fetch" {
+  ctx="$(_section 'Context-gathering' "$SINGLE")"
+  grep -q 'gh pr view' <<<"$ctx"
+  grep -q 'gh pr diff' <<<"$ctx"
+}
+
+@test "single-review prompt preserves the draft / head-sha-changed skip checks" {
+  # The step-1 skip guards must not be lost when rewiring the fetch — they gate
+  # off the metadata regardless of whether it was pre-fed or fetched live.
+  grep -q 'isDraft' "$SINGLE"
+  grep -q 'head-sha-changed' "$SINGLE"
+}
+
+# --- cascade-action.md (AC #4: confirmed out of scope) ----------------------
+
+@test "cascade-action prompt is documented as not fetching the diff (out of scope)" {
+  # It synthesizes prior verdicts from $FINAL_RESULT and never fetches the diff,
+  # so it needs no pre-fed-context rewire — documented explicitly per AC #4.
+  grep -Eiq 'does not fetch|no.*fetch|out of scope|synthes' "$ACTION"
+  # Verify implementation: cascade-action must contain no live fetch commands.
+  ! grep -q 'gh pr view' "$ACTION"
+  ! grep -q 'gh pr diff' "$ACTION"
+}