diff --git a/src/tools/merge_pr.mbt b/src/tools/merge_pr.mbt
index 44bcfa16..40869b72 100644
--- a/src/tools/merge_pr.mbt
+++ b/src/tools/merge_pr.mbt
@@ -685,6 +685,8 @@ async fn merge_pr_audit_receipt_validation_for_head(
   project_dir : String,
   head_sha : String,
   capture : async (@workspace.Command) -> (Int, String),
+  read_file : (String) -> String,
+  path_exists : (String) -> Bool,
 ) -> MergePrAuditReceiptValidation {
   let tree_sha = match
     audit_receipt_tree_sha_for_head(project_dir, head_sha, capture) {
@@ -692,21 +694,180 @@ async fn merge_pr_audit_receipt_validation_for_head(
     None => return MergeAuditReceiptTreeUnavailable(file_pr_short_sha(head_sha))
   }
   let receipt_path = file_pr_audit_receipt_path_for_head(tree_sha)
-  let (exit_code, receipt_body) = capture({
-    program: "cat",
-    args: [receipt_path],
-    workdir: Some(project_dir),
-  })
+  let receipt_path = project_relative_path(project_dir, receipt_path)
+  let receipt_body = if path_exists(receipt_path) {
+    Some(read_file(receipt_path))
+  } else {
+    None
+  }
   merge_pr_audit_receipt_validation(
-    parent_branch,
-    default_branch,
-    tree_sha,
-    if exit_code == 0 {
-      Some(receipt_body)
-    } else {
-      None
+    parent_branch, default_branch, tree_sha, receipt_body,
+  )
+}
+
+///|
+async test "merge_pr audit receipt validation reports missing receipt without reading it" {
+  let head = "abcdef1234567890abcdef1234567890abcdef12"
+  let tree = "9999999999999999999999999999999999999999"
+  let captured : Array[@workspace.Command] = []
+  let mut read_calls = 0
+  let got = merge_pr_audit_receipt_validation_for_head(
+    "main",
+    "main",
+    "/repo",
+    head,
+    async fn(cmd : @workspace.Command) -> (Int, String) {
+      @async.sleep(0)
+      captured.push(cmd)
+      if cmd.program == "git" {
+        (0, tree + "\n")
+      } else {
+        (1, "")
+      }
+    },
+    fn(_) {
+      read_calls = read_calls + 1
+      ""
+    },
+    fn(_) { false },
+  )
+  match got {
+    MergeAuditReceiptMissing(short_sha) =>
+      @debug.assert_eq(short_sha, file_pr_short_sha(tree))
+    _ => fail("expected missing receipt")
+  }
+  @debug.assert_eq(captured.length(), 1)
+  @debug.assert_eq(captured[0].program, "git")
+  @debug.assert_eq(read_calls, 0)
+}
+
+///|
+async test "merge_pr audit receipt validation parses an injected receipt body" {
+  let head = "abcdef1234567890abcdef1234567890abcdef12"
+  let tree = "9999999999999999999999999999999999999999"
+  let receipt : @types.AuditReceipt = {
+    sha: head,
+    tree_sha: tree,
+    branch: "main",
+    audited_at: 1L,
+    agent_id: "main.tl",
+    findings_count: 0,
+    findings: Some(""),
+  }
+  let receipt_body = receipt.to_json().stringify() + "\n"
+  let receipt_paths : Array[String] = []
+  let got = merge_pr_audit_receipt_validation_for_head(
+    "main",
+    "main",
+    "/repo",
+    head,
+    async fn(cmd : @workspace.Command) -> (Int, String) {
+      @async.sleep(0)
+      if cmd.program == "git" {
+        (0, tree + "\n")
+      } else {
+        (1, "")
+      }
+    },
+    fn(path) {
+      receipt_paths.push(path)
+      receipt_body
+    },
+    fn(path) {
+      receipt_paths.push(path)
+      true
+    },
+  )
+  match got {
+    MergeAuditReceiptValid => ()
+    _ => fail("expected injected valid receipt")
+  }
+  @debug.assert_eq(receipt_paths, [
+    project_relative_path("/repo", file_pr_audit_receipt_path_for_head(tree)),
+    project_relative_path("/repo", file_pr_audit_receipt_path_for_head(tree)),
+  ])
+}
+
+///|
+async test "merge_pr audit receipt validation only captures git tree resolution" {
+  let head = "abcdef1234567890abcdef1234567890abcdef12"
+  let tree = "9999999999999999999999999999999999999999"
+  let programs : Array[String] = []
+  let got = merge_pr_audit_receipt_validation_for_head(
+    "main",
+    "main",
+    "/repo",
+    head,
+    async fn(cmd : @workspace.Command) -> (Int, String) {
+      @async.sleep(0)
+      programs.push(cmd.program)
+      if cmd.program == "git" {
+        (0, tree + "\n")
+      } else {
+        (1, "")
+      }
+    },
+    fn(_) {
+      "{\"sha\":\"" +
+      head +
+      "\",\"tree_sha\":\"" +
+      tree +
+      "\",\"branch\":\"main\",\"audited_at\":1,\"agent_id\":\"main.tl\",\"findings_count\":0,\"findings\":\"\"}"
+    },
+    fn(_) { true },
+  )
+  match got {
+    MergeAuditReceiptValid => ()
+    _ => fail("expected valid receipt")
+  }
+  @debug.assert_eq(programs, ["git"])
+}
+
+///|
+async test "merge_pr audit receipt validation reads receipt under project directory" {
+  let project_dir = "/tmp/choir-merge-pr-receipt-project-" +
+    @sys.get_pid().to_string()
+  let head = "abcdef1234567890abcdef1234567890abcdef12"
+  let tree = "9999999999999999999999999999999999999999"
+  ignore(@sys.rm_rf(project_dir))
+  assert_true(@sys.create_dir_all(project_dir + "/.choir/state/audit-receipts"))
+  let receipt_path = project_relative_path(
+    project_dir,
+    file_pr_audit_receipt_path_for_head(tree),
+  )
+  let receipt : @types.AuditReceipt = {
+    sha: head,
+    tree_sha: tree,
+    branch: "main",
+    audited_at: 1L,
+    agent_id: "main.tl",
+    findings_count: 0,
+    findings: Some(""),
+  }
+  assert_true(
+    @sys.write_file_sync(receipt_path, receipt.to_json().stringify() + "\n"),
+  )
+  let got = merge_pr_audit_receipt_validation_for_head(
+    "main",
+    "main",
+    project_dir,
+    head,
+    async fn(cmd : @workspace.Command) -> (Int, String) {
+      @async.sleep(0)
+      if cmd.program == "git" {
+        (0, tree + "\n")
+      } else {
+        (1, "")
+      }
     },
+    @sys.read_file,
+    @sys.path_entry_exists,
   )
+  match got {
+    MergeAuditReceiptValid => ()
+    _ => fail("expected receipt under project directory to validate")
+  }
+  ignore(@sys.rm_rf(project_dir))
 }
 
 ///|
@@ -808,6 +969,8 @@ pub async fn merge_pr_require_audit_receipt(
   gate_state : MergeGateState,
   pr_first_seen_unix : Int64,
   capture : async (@workspace.Command) -> (Int, String),
+  read_file? : (String) -> String = @sys.read_file,
+  path_exists? : (String) -> Bool = @sys.path_entry_exists,
   append_file? : (String, String) -> Bool = fn(_, _) { false },
 ) -> Result[Unit, @types.ChoirError] {
   if !file_pr_audit_receipt_required(parent_branch, default_branch) {
@@ -827,7 +990,7 @@ pub async fn merge_pr_require_audit_receipt(
     )
   }
   let validation = merge_pr_audit_receipt_validation_for_head(
-    parent_branch, default_branch, project_dir, head_sha, capture,
+    parent_branch, default_branch, project_dir, head_sha, capture, read_file, path_exists,
   )
   match validation {
     MergeAuditReceiptValid => Ok(())
@@ -2380,6 +2543,8 @@ pub async fn interpret_merge_pr(
                 gate_state,
                 tracked.first_seen,
                 capture,
+                read_file~,
+                path_exists~,
                 append_file~,
               ) {
               Err(e) => return @types.Response::Err(e.message())
diff --git a/src/tools/merge_pr_test.mbt b/src/tools/merge_pr_test.mbt
index c3f4b11c..6661dafd 100644
--- a/src/tools/merge_pr_test.mbt
+++ b/src/tools/merge_pr_test.mbt
@@ -639,9 +639,6 @@ async test "interpret_merge_pr missing audit receipt policy-blocks on master def
       if cmd.program == "git" && cmd.args == ["rev-parse", head + "^{tree}"] {
         return (0, head + "\n")
       }
-      if cmd.program == "cat" {
-        return (1, "")
-      }
       (1, "spawn failed")
     },
     fn(_path, content) {
@@ -755,9 +752,6 @@ async test "interpret_merge_pr blocks when default branch detection fails" {
         cmd.args == ["rev-parse", "--abbrev-ref", "HEAD"] {
         return (0, "feature/audit-gate\n")
       }
-      if cmd.program == "cat" {
-        return (1, "")
-      }
       (0, "")
     },
     fn(_path, content) {
@@ -819,7 +813,6 @@ async test "interpret_merge_pr audit receipt remains valid when commit changes b
     @poller.CiRollupStatus::Success,
     true,
   )
-  let cat_paths : Array[String] = []
   let mut runner_calls = 0
   let resp = interpret_merge_pr(
     {
@@ -868,20 +861,20 @@ async test "interpret_merge_pr audit receipt remains valid when commit changes b
       if cmd.program == "git" && cmd.args == ["rev-parse", head + "^{tree}"] {
         return (0, tree + "\n")
       }
-      if cmd.program == "cat" {
-        cat_paths.push(cmd.args[0])
-        return (
-          0,
-          merge_pr_test_audit_receipt_for_tree(audited_commit, tree, 0),
-        )
-      }
       (0, "")
     },
     fn(_, _) { true },
-    fn(path) { path.has_suffix("/.choir/state/audit-gate.json") },
+    fn(path) {
+      path.has_suffix("/.choir/state/audit-gate.json") ||
+      path.contains("/.choir/state/audit-receipts/") ||
+      path.has_prefix(".choir/state/audit-receipts/")
+    },
     read_file=fn(path) {
       if path.has_suffix("/.choir/state/audit-gate.json") {
         "{\"enabled_at_unix\":100}\n"
+      } else if path.contains("/.choir/state/audit-receipts/") ||
+        path.has_prefix(".choir/state/audit-receipts/") {
+        merge_pr_test_audit_receipt_for_tree(audited_commit, tree, 0)
       } else {
         ""
       }
@@ -893,7 +886,6 @@ async test "interpret_merge_pr audit receipt remains valid when commit changes b
     @types.Response::Err(msg) => fail("expected merge success: " + msg)
   }
   assert_eq(runner_calls, 1)
-  @debug.assert_eq(cat_paths, [file_pr_audit_receipt_path_for_head(tree)])
   ignore(@sys.rm_rf(project_dir))
 }
 
@@ -1233,16 +1225,20 @@ async test "interpret_merge_pr main audit gate merges only matching audited head
       if cmd.program == "git" && cmd.args == ["rev-parse", head + "^{tree}"] {
         return (0, head + "\n")
       }
-      if cmd.program == "cat" {
-        return (0, merge_pr_test_audit_receipt(head))
-      }
       (0, "")
     },
     fn(_, _) { true },
-    fn(path) { path.has_suffix("/.choir/state/audit-gate.json") },
+    fn(path) {
+      path.has_suffix("/.choir/state/audit-gate.json") ||
+      path.contains("/.choir/state/audit-receipts/") ||
+      path.has_prefix(".choir/state/audit-receipts/")
+    },
     read_file=fn(path) {
       if path.has_suffix("/.choir/state/audit-gate.json") {
         "{\"enabled_at_unix\":100}\n"
+      } else if path.contains("/.choir/state/audit-receipts/") ||
+        path.has_prefix(".choir/state/audit-receipts/") {
+        merge_pr_test_audit_receipt(head)
       } else {
         ""
       }
@@ -1329,9 +1325,6 @@ async test "interpret_merge_pr success fires pr_merged completion hooks" {
       if cmd.program == "git" && cmd.args == ["rev-parse", head + "^{tree}"] {
         return (0, head + "\n")
       }
-      if cmd.program == "cat" {
-        return (0, merge_pr_test_audit_receipt(head))
-      }
       (0, "")
     },
     fn(_, _) { true },
@@ -1339,7 +1332,8 @@ async test "interpret_merge_pr success fires pr_merged completion hooks" {
       path.has_suffix("/.choir/state/audit-gate.json") ||
       path.has_suffix("/.choir/hooks/pr_merged.sh") ||
       path.has_suffix("/.choir/hooks/wave_complete.sh") ||
-      path.has_suffix("/.choir/state/audit-receipts/abcdef123456.json")
+      path.has_suffix("/.choir/state/audit-receipts/abcdef123456.json") ||
+      path.has_prefix(".choir/state/audit-receipts/")
     },
     hook_capture=async fn(
       path : String,
@@ -1362,7 +1356,8 @@ async test "interpret_merge_pr success fires pr_merged completion hooks" {
         "{\"enabled_at_unix\":100}\n"
       } else if path.has_suffix(
           "/.choir/state/audit-receipts/abcdef123456.json",
-        ) {
+        ) ||
+        path.has_prefix(".choir/state/audit-receipts/") {
         merge_pr_test_audit_receipt(head)
       } else {
         ""
@@ -1462,9 +1457,6 @@ async test "interpret_merge_pr suppresses pr_merged hooks when poller persist fa
       if cmd.program == "git" && cmd.args == ["rev-parse", head + "^{tree}"] {
         return (0, head + "\n")
       }
-      if cmd.program == "cat" {
-        return (0, merge_pr_test_audit_receipt(head))
-      }
       (0, "")
     },
     fn(_, _) { true },
@@ -1472,7 +1464,8 @@ async test "interpret_merge_pr suppresses pr_merged hooks when poller persist fa
       path.has_suffix("/.choir/state/audit-gate.json") ||
       path.has_suffix("/.choir/hooks/pr_merged.sh") ||
       path.has_suffix("/.choir/hooks/wave_complete.sh") ||
-      path.has_suffix("/.choir/state/audit-receipts/abcdef123456.json")
+      path.has_suffix("/.choir/state/audit-receipts/abcdef123456.json") ||
+      path.has_prefix(".choir/state/audit-receipts/")
     },
     hook_capture=async fn(
       path : String,
@@ -1488,7 +1481,8 @@ async test "interpret_merge_pr suppresses pr_merged hooks when poller persist fa
         "{\"enabled_at_unix\":100}\n"
       } else if path.has_suffix(
           "/.choir/state/audit-receipts/abcdef123456.json",
-        ) {
+        ) ||
+        path.has_prefix(".choir/state/audit-receipts/") {
         merge_pr_test_audit_receipt(head)
       } else {
         ""
@@ -3648,12 +3642,6 @@ async test "interpret_merge_pr tracked feature merge skips audit gate file and r
       receipt_captures = receipt_captures + 1
       return (1, "")
     }
-    if cmd.program == "cat" &&
-      cmd.args.length() == 1 &&
-      cmd.args[0].has_prefix(".choir/state/audit-receipts/") {
-      receipt_captures = receipt_captures + 1
-      return (1, "")
-    }
     mock_preflight_capture_no_unresolved_threads(cmd)
   }
   let got = interpret_merge_pr(
diff --git a/src/tools/pr_merged_completion_hooks.mbt b/src/tools/pr_merged_completion_hooks.mbt
index 6be38eae..a8974610 100644
--- a/src/tools/pr_merged_completion_hooks.mbt
+++ b/src/tools/pr_merged_completion_hooks.mbt
@@ -212,7 +212,8 @@ pub async fn audit_receipt_advisory_state_for_tracked_pr(
   }
   match
     merge_pr_audit_receipt_validation_for_head(
-      parent_branch, default_branch, project_dir, trimmed_head, capture,
+      parent_branch, default_branch, project_dir, trimmed_head, capture, read_file,
+      path_exists,
     ) {
     MergeAuditReceiptValid => @types.AuditReceiptState::Valid
     MergeAuditReceiptFindingsRemain(sha, count) =>
diff --git a/src/tools/pr_merged_completion_hooks_test.mbt b/src/tools/pr_merged_completion_hooks_test.mbt
index 64da8530..a65933f4 100644
--- a/src/tools/pr_merged_completion_hooks_test.mbt
+++ b/src/tools/pr_merged_completion_hooks_test.mbt
@@ -14,6 +14,27 @@ fn hooks_test_gate_path_exists(path : String) -> Bool {
   path.has_suffix("/.choir/state/audit-gate.json")
 }
 
+///|
+fn hooks_test_receipt_path_exists(path : String) -> Bool {
+  path.has_suffix("/.choir/state/audit-gate.json") ||
+  path.contains("/.choir/state/audit-receipts/") ||
+  path.has_prefix(".choir/state/audit-receipts/")
+}
+
+///|
+fn hooks_test_read_file_with_receipt(
+  enabled_at_unix : Int64,
+  receipt_body : String,
+) -> (String) -> String {
+  fn(path : String) -> String {
+    if path.has_suffix("/.choir/state/audit-gate.json") {
+      "{\"enabled_at_unix\":" + enabled_at_unix.to_string() + "}\n"
+    } else {
+      receipt_body
+    }
+  }
+}
+
 ///|
 fn hooks_test_receipt_for_tree(
   tree_sha : String,
@@ -99,11 +120,11 @@ async test "audit receipt advisory uses resolved default branch on success" {
       if cmd.program == "git" {
         (0, tree + "\n")
       } else {
-        (0, hooks_test_receipt_for_tree(tree, 0))
+        (1, "")
       }
     },
-    hooks_test_gate_state_reader(1L),
-    hooks_test_gate_path_exists,
+    hooks_test_read_file_with_receipt(1L, hooks_test_receipt_for_tree(tree, 0)),
+    hooks_test_receipt_path_exists,
     default_branch_result=Some(default_branch),
   )
   assert_eq(state, @types.AuditReceiptState::Valid)
@@ -170,11 +191,11 @@ async test "audit_receipt_advisory_state_for_tracked_pr maps gate and receipt st
       if cmd.program == "git" {
         (0, tree + "\n")
       } else {
-        (0, hooks_test_receipt_for_tree(tree, 0))
+        (1, "")
       }
     },
-    hooks_test_gate_state_reader(1L),
-    hooks_test_gate_path_exists,
+    hooks_test_read_file_with_receipt(1L, hooks_test_receipt_for_tree(tree, 0)),
+    hooks_test_receipt_path_exists,
   )
   assert_eq(valid, @types.AuditReceiptState::Valid)
 
@@ -189,11 +210,11 @@ async test "audit_receipt_advisory_state_for_tracked_pr maps gate and receipt st
       if cmd.program == "git" {
         (0, tree + "\n")
       } else {
-        (0, hooks_test_receipt_for_tree(tree, 3))
+        (1, "")
       }
     },
-    hooks_test_gate_state_reader(1L),
-    hooks_test_gate_path_exists,
+    hooks_test_read_file_with_receipt(1L, hooks_test_receipt_for_tree(tree, 3)),
+    hooks_test_receipt_path_exists,
   )
   assert_eq(
     findings,
@@ -236,11 +257,11 @@ async test "audit_receipt_advisory_state_for_tracked_pr maps gate and receipt st
       if cmd.program == "git" {
         (0, tree + "\n")
       } else {
-        (0, "{not json")
+        (1, "")
       }
     },
-    hooks_test_gate_state_reader(1L),
-    hooks_test_gate_path_exists,
+    hooks_test_read_file_with_receipt(1L, "{not json"),
+    hooks_test_receipt_path_exists,
   )
   assert_eq(
     invalid,
@@ -258,11 +279,14 @@ async test "audit_receipt_advisory_state_for_tracked_pr maps gate and receipt st
       if cmd.program == "git" {
         (0, tree + "\n")
       } else {
-        (0, hooks_test_receipt_for_tree(other_tree, 0))
+        (1, "")
       }
     },
-    hooks_test_gate_state_reader(1L),
-    hooks_test_gate_path_exists,
+    hooks_test_read_file_with_receipt(
+      1L,
+      hooks_test_receipt_for_tree(other_tree, 0),
+    ),
+    hooks_test_receipt_path_exists,
   )
   assert_eq(stale, @types.AuditReceiptState::Pending(head_sha=tree))