diff --git a/claude-plugins/plugins/base/skills/forge-triage/SKILL.md b/claude-plugins/plugins/base/skills/forge-triage/SKILL.md
index 01b60fbb..ffc96883 100644
--- a/claude-plugins/plugins/base/skills/forge-triage/SKILL.md
+++ b/claude-plugins/plugins/base/skills/forge-triage/SKILL.md
@@ -30,7 +30,10 @@ dimension directly.
   neglected owner.
 - **Stale branches** - `hive-forge lint stale-branches --days <n>`
   finds remote branches with no recent commits (skips branches that are
-  heads of open PRs), useful for spotting abandoned work.
+  heads of open PRs) and reports each one's merge outcome (PR merged /
+  closed unmerged / no PR at all) — squash-merge ancestry can't tell
+  those apart, so don't delete a stale branch on the age alone; check
+  the verdict first.
 
 ## Using them as a sweep
 
diff --git a/docs/tools/forge.md b/docs/tools/forge.md
index 6ec5581a..b7f7d3fd 100644
--- a/docs/tools/forge.md
+++ b/docs/tools/forge.md
@@ -85,7 +85,7 @@ hive-forge -r other-org/other-repo pr 7     # target a different repo
 hive-forge lint unassigned                  # open issues/PRs with no assignee
 hive-forge lint no-reviewer                   # PRs with zero formally requested reviewers
 hive-forge lint no-reviewer --reviewer argus  # PRs where argus specifically isn't a requested reviewer
-hive-forge lint stale-branches --days 14    # branches with no recent activity
+hive-forge lint stale-branches --days 14    # branches with no recent activity, each with its merge outcome (PR #n merged / closed unmerged / no PR)
 hive-forge lint assignments                 # per-assignee open item count
 hive-forge lint unlabeled --scope type      # open issues/PRs with no exclusive type/* label (any scope works, e.g. --scope area)
 hive-forge pr-status --pr 42                # PR health: mergeable, CI, reviews, last comment (exit 0 = ready)
diff --git a/hive-forge/src/verbs/lint.rs b/hive-forge/src/verbs/lint.rs
index fffdb986..287de2f5 100644
--- a/hive-forge/src/verbs/lint.rs
+++ b/hive-forge/src/verbs/lint.rs
@@ -15,8 +15,8 @@ use std::collections::BTreeMap;
 use anyhow::{Result, bail};
 use clap::{Args as ClapArgs, Subcommand, ValueEnum};
 use forgejo_api::structs::{
-    Issue, IssueListIssuesQuery, IssueListIssuesQueryState, IssueListIssuesQueryType,
-    RepoListPullRequestsQuery, RepoListPullRequestsQueryState,
+    Issue, IssueListIssuesQuery, IssueListIssuesQueryState, IssueListIssuesQueryType, PullRequest,
+    RepoListPullRequestsQuery, RepoListPullRequestsQueryState, StateType,
 };
 use serde_json::{Value, json};
 use time::OffsetDateTime;
@@ -43,8 +43,8 @@ enum Sub {
     Unassigned(UnassignedArgs),
     /// List PRs with no formally requested reviewer.
     NoReviewer(NoReviewerArgs),
-    /// List remote branches with no commits in N days.
-    /// Skips branches that are heads of open PRs.
+    /// List remote branches with no commits in N days, each with its
+    /// merge outcome (skips branches that are heads of open PRs).
     StaleBranches(StaleBranchesArgs),
     /// Group open issues + PRs by assignee.
     Assignments(AssignmentsArgs),
@@ -281,12 +281,18 @@ fn run_stale_branches(client: &Client, args: StaleBranchesArgs) -> Result<()> {
             break;
         }
     }
-    // Collect active PR head refs to skip — a branch with an open PR
-    // isn't "stale", it's "in review".
-    let mut active_heads: std::collections::HashSet<String> = std::collections::HashSet::new();
+    // One pass over every PR, any state, doing double duty: an open
+    // head isn't "stale", it's "in review" (skip-list, as before), and
+    // a closed one tells a surviving stale branch its actual fate —
+    // merged (branch is a leftover copy, safe to delete) vs. closed
+    // unmerged / never had a PR (the branch is the only copy). Because
+    // hyperhive squash-merges, a merged branch's tip is never an
+    // ancestor of main, so ancestry can't tell these apart; this is the
+    // only signal that can.
+    let mut prs = Vec::new();
     for page in 1..=MAX_PAGES {
         let query = RepoListPullRequestsQuery {
-            state: Some(RepoListPullRequestsQueryState::Open),
+            state: Some(RepoListPullRequestsQueryState::All),
             ..Default::default()
         };
         let (_, batch) = client
@@ -296,15 +302,30 @@ fn run_stale_branches(client: &Client, args: StaleBranchesArgs) -> Result<()> {
             .page_size(PAGE_LIMIT)
             .send()?;
         let short = batch.len() < PAGE_LIMIT as usize;
-        active_heads.extend(
-            batch
-                .iter()
-                .filter_map(|p| p.head.as_ref().and_then(|h| h.r#ref.clone())),
-        );
+        prs.extend(batch);
         if short {
             break;
         }
     }
+    let mut active_heads: std::collections::HashSet<String> = std::collections::HashSet::new();
+    // Highest-numbered (most recent) PR per head branch, in case a
+    // branch name was reused across more than one PR over its life.
+    let mut latest_pr_by_head: std::collections::HashMap<String, &PullRequest> =
+        std::collections::HashMap::new();
+    for pr in &prs {
+        let Some(head_ref) = pr.head.as_ref().and_then(|h| h.r#ref.clone()) else {
+            continue;
+        };
+        if pr.state == Some(StateType::Open) {
+            active_heads.insert(head_ref.clone());
+        }
+        let is_newer = latest_pr_by_head
+            .get(&head_ref)
+            .is_none_or(|existing| pr.number.unwrap_or(0) > existing.number.unwrap_or(0));
+        if is_newer {
+            latest_pr_by_head.insert(head_ref, pr);
+        }
+    }
 
     let today = OffsetDateTime::now_utc().date();
     let mut stale: Vec<Value> = Vec::new();
@@ -320,17 +341,31 @@ fn run_stale_branches(client: &Client, args: StaleBranchesArgs) -> Result<()> {
         // date-granular, matching the old YYYY-MM-DD prefix math.
         let age_days = (today - ts.date()).whole_days();
         if age_days >= args.days {
+            // A branch surviving to here can only have a *closed* PR
+            // (an open one would already be in `active_heads`), so
+            // `merged` is unambiguous when a PR exists at all.
+            let pr = latest_pr_by_head.get(branch_name);
             stale.push(json!({
                 "name": branch_name,
                 "last_commit": rfc3339(Some(ts)),
                 "age_days": age_days,
+                "pr": pr.and_then(|p| p.number),
+                "merged": pr.and_then(|p| p.merged),
             }));
         }
     }
     emit(client, &stale, |it| {
         let name = it.get("name").and_then(Value::as_str).unwrap_or("?");
         let age = it.get("age_days").and_then(Value::as_i64).unwrap_or(0);
-        format!("{name} ({age}d)")
+        let verdict = match (
+            it.get("pr").and_then(Value::as_i64),
+            it.get("merged").and_then(Value::as_bool),
+        ) {
+            (Some(pr), Some(true)) => format!("PR #{pr} merged"),
+            (Some(pr), Some(false)) => format!("PR #{pr} closed, not merged"),
+            _ => "no PR".to_string(),
+        };
+        format!("{name} ({age}d) — {verdict}")
     })
 }