From f490e0750930797d0a969a659f2d71e1e8d5c83b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?m=C3=BCde?= <git@darkest.space>
Date: Sun, 5 Jul 2026 22:36:10 +0200
Subject: [PATCH] refactor(prompt): drop unreachable role-block defensive
 branches; keep marker grammar

---
 docs/turn-loop.md        | 16 +++++-----
 hive-ag3nt/src/prompt.rs | 68 ++++++----------------------------------
 2 files changed, 17 insertions(+), 67 deletions(-)

diff --git a/docs/turn-loop.md b/docs/turn-loop.md
index 3e9d75f0..70aee411 100644
--- a/docs/turn-loop.md
+++ b/docs/turn-loop.md
@@ -350,14 +350,14 @@ socket at `/run/hive/` once at startup:
   favour of this direct injection).
   Passed via `--system-prompt-file`.
 
-  **Marker grammar.** `<!-- role:X -->` opens a block; matching
-  `<!-- /role:X -->` closes it. The renderer always uses role `agent`.
-  Blocks with other role tags are elided. Nesting is NOT supported —
-  a stray opener overrides until its closing tag (or end of file). A
-  mismatched closer is elided from the output but does NOT pop the
-  active role. Whitespace inside markers is tolerated
-  (`<!--role:foo-->` parses the same as `<!-- role:foo -->`).
-  Content outside any marker is always included.
+  **Marker grammar.** `<!-- role:X -->` opens a block; any
+  `<!-- /role:X -->` closes the current block. The renderer always uses
+  role `agent`, so blocks with other role tags are elided. Nesting is NOT
+  supported — a stray opener with no closer runs until end of file.
+  Whitespace inside markers is tolerated (`<!--role:foo-->` parses the
+  same as `<!-- role:foo -->`). Content outside any marker is always
+  included. Today's `system.md` carries no markers (single agent role) —
+  the grammar stays wired for a future manager / multi-role prompt.
 
   **`hive_identity` / `swarm_identity` shape.** Each carries a
   leading space + backticked name (` on hive \`pr1ma\``,
diff --git a/hive-ag3nt/src/prompt.rs b/hive-ag3nt/src/prompt.rs
index aa584747..5c2e8e01 100644
--- a/hive-ag3nt/src/prompt.rs
+++ b/hive-ag3nt/src/prompt.rs
@@ -55,14 +55,12 @@ pub fn render(
     }
 }
 
-/// Walk `template` line-by-line. Inside a `<!-- role:X -->` block,
-/// suppress all lines unless `X == target`. Marker lines themselves are
-/// always elided from the output. Unbalanced openers (no matching
-/// closer) hold the suppression state until end-of-file. A mismatched
-/// closer (`<!-- /role:manager -->` inside a `role:agent` block) is
-/// elided from the output but does NOT reset the active role — keeps
-/// the suppression conservative so a typo can't dump wrong-flavor
-/// content.
+/// Walk `template` line-by-line, stripping `<!-- role:X -->` /
+/// `<!-- /role:X -->` marker lines and suppressing the lines inside a block
+/// unless `X == target`. A close marker ends the current block. Production
+/// `system.md` carries no markers today (single agent role — see the module
+/// doc), so this is effectively a passthrough; the marker grammar stays wired
+/// for a future manager / multi-role prompt.
 fn filter_role_blocks(template: &str, target: &str) -> String {
     let mut out = String::with_capacity(template.len());
     // None = outside any block; Some(role) = inside role-tagged block.
@@ -73,19 +71,11 @@ fn filter_role_blocks(template: &str, target: &str) -> String {
             active_role = Some(role);
             continue;
         }
-        if let Some(close_role) = parse_close_marker(trimmed) {
-            if active_role == Some(close_role) {
-                active_role = None;
-            }
-            // Mismatched close: elide the marker line but keep the
-            // active role intact so wrong-flavor content stays gated.
+        if parse_close_marker(trimmed).is_some() {
+            active_role = None;
             continue;
         }
-        let include = match active_role {
-            None => true,
-            Some(role) => role == target,
-        };
-        if include {
+        if active_role.is_none_or(|role| role == target) {
             out.push_str(line);
             out.push('\n');
         }
@@ -245,46 +235,6 @@ shared closer
         assert_eq!(parse_close_marker("just text"), None);
     }
 
-    #[test]
-    fn mismatched_close_keeps_active_role() {
-        // `<!-- role:agent -->` block with a stray `<!-- /role:manager -->`
-        // closer inside: the manager-tagged close must NOT pop the agent
-        // gate, else manager-target output would leak the agent block's
-        // text (or vice-versa). Stray marker line itself is still elided.
-        let template = "shared\n\
-                        <!-- role:agent -->\n\
-                        agent line 1\n\
-                        <!-- /role:manager -->\n\
-                        agent line 2\n\
-                        <!-- /role:agent -->\n\
-                        shared end\n";
-        let manager = filter_role_blocks(template, "manager");
-        // Both agent lines stay gated out for the manager target; the
-        // stray close didn't accidentally pop the role. Stray marker
-        // itself elided from the output.
-        assert!(!manager.contains("agent line 1"));
-        assert!(!manager.contains("agent line 2"));
-        assert!(!manager.contains("<!--"));
-        assert!(manager.contains("shared"));
-        assert!(manager.contains("shared end"));
-        // Agent target still sees both lines (matched closer pops at the end).
-        let agent = filter_role_blocks(template, "agent");
-        assert!(agent.contains("agent line 1"));
-        assert!(agent.contains("agent line 2"));
-        assert!(agent.contains("shared end"));
-    }
-
-    #[test]
-    fn unbalanced_opener_suppresses_until_eof() {
-        // Stray opener with no closer — content stays suppressed for
-        // the wrong-role target right through to end-of-file. Real-
-        // file safety net: a typo in a closer doesn't accidentally
-        // dump wrong-flavor content into the active prompt.
-        let template = "shared\n<!-- role:manager -->\nm-only\nstill m-only\n";
-        let agent = filter_role_blocks(template, "agent");
-        assert_eq!(agent, "shared\n");
-    }
-
     #[test]
     fn render_substitutes_label_and_pronouns() {
         // Real template's first agent line — keeps the renderer