diff --git a/.claude/commands/coverage.md b/.claude/commands/coverage.md
new file mode 100644
index 00000000..34815b24
--- /dev/null
+++ b/.claude/commands/coverage.md
@@ -0,0 +1,21 @@
+Show test coverage from the cached `.coverage_baseline` file, or rerun the full test suite with `$ARGUMENTS`.
+
+## Usage
+
+- `/coverage` — read cached coverage from `.coverage_baseline` (instant)
+- `/coverage run` — run `script/test_coverage` and report fresh results
+
+## What it does
+
+**Cached mode (default):** Reads `.coverage_baseline` and displays the stored coverage percentage(s). This is instant and does not run any tests.
+
+**Run mode (`run`):** Executes `script/test_coverage` which runs:
+1. Rust tests with `cargo llvm-cov` (reports line coverage %)
+2. Frontend tests with `npm run test:coverage` (reports line coverage %)
+3. Computes the overall average and compares to the threshold
+
+Reports Rust coverage, Frontend coverage, Overall coverage, and whether the run passed the threshold.
+
+---
+
+If the arguments (`$ARGUMENTS`) equal `run`, execute `bash script/test_coverage` from the project root and show the Coverage Summary section from the output. Otherwise, read `.coverage_baseline` and display the stored coverage value(s).
diff --git a/server/src/chat/commands/coverage.rs b/server/src/chat/commands/coverage.rs
new file mode 100644
index 00000000..7d098b2f
--- /dev/null
+++ b/server/src/chat/commands/coverage.rs
@@ -0,0 +1,343 @@
+//! Handler for the `coverage` command — show or refresh test coverage.
+//!
+//! Default (no args): reads the cached `.coverage_baseline` file and reports
+//! the stored value instantly without running the test suite.
+//!
+//! `coverage run`: executes `script/test_coverage` to collect fresh coverage
+//! data, parses the summary, and reports the result.
+
+use super::CommandContext;
+
+const BASELINE_FILE: &str = ".coverage_baseline";
+const COVERAGE_SCRIPT: &str = "script/test_coverage";
+
+pub(super) fn handle_coverage(ctx: &CommandContext) -> Option<String> {
+    let args = ctx.args.trim();
+
+    match args {
+        "run" => Some(run_coverage(ctx.project_root)),
+        "" => Some(read_cached_coverage(ctx.project_root)),
+        other => Some(format!(
+            "Usage: `coverage` (cached) or `coverage run` (fresh)\n\nUnknown argument: `{other}`"
+        )),
+    }
+}
+
+/// Read coverage from `.coverage_baseline` and return a formatted report.
+fn read_cached_coverage(project_root: &std::path::Path) -> String {
+    let baseline_path = project_root.join(BASELINE_FILE);
+
+    match std::fs::read_to_string(&baseline_path) {
+        Ok(content) => {
+            let lines: Vec<&str> = content.lines().filter(|l| !l.trim().is_empty()).collect();
+            if lines.is_empty() {
+                return "**Coverage (cached)**\n\nNo baseline data found.\n\n*Run `coverage run` to collect coverage.*".to_string();
+            }
+            format_cached_coverage(&lines)
+        }
+        Err(e) if e.kind() == std::io::ErrorKind::NotFound => {
+            "**Coverage (cached)**\n\nNo `.coverage_baseline` file found.\n\n*Run `coverage run` to collect coverage.*".to_string()
+        }
+        Err(e) => format!("**Coverage (cached)**\n\nError reading `.coverage_baseline`: {e}"),
+    }
+}
+
+/// Format cached coverage lines for display.
+///
+/// The baseline file stores the last overall coverage percentage written by
+/// `script/test_coverage`.  It always contains one line (the overall percentage)
+/// but may have been seeded manually with two lines (Rust + Frontend baselines).
+fn format_cached_coverage(lines: &[&str]) -> String {
+    let mut out = "**Coverage (cached)**\n\n".to_string();
+    if lines.len() == 2 {
+        out.push_str(&format!("Rust:     {}%\n", lines[0].trim()));
+        out.push_str(&format!("Frontend: {}%\n", lines[1].trim()));
+    } else {
+        out.push_str(&format!("Overall: {}%\n", lines[0].trim()));
+    }
+    out.push_str("\n*Run `coverage run` for fresh results.*");
+    out
+}
+
+/// Run `script/test_coverage`, parse its summary, and return a formatted report.
+fn run_coverage(project_root: &std::path::Path) -> String {
+    let script_path = project_root.join(COVERAGE_SCRIPT);
+
+    if !script_path.exists() {
+        return format!(
+            "**Coverage**\n\nCoverage script not found: `{COVERAGE_SCRIPT}`\n\nEnsure `{COVERAGE_SCRIPT}` exists in the project root."
+        );
+    }
+
+    let output = std::process::Command::new("bash")
+        .arg(&script_path)
+        .current_dir(project_root)
+        .output();
+
+    match output {
+        Err(e) => format!("**Coverage**\n\nFailed to run coverage script: {e}"),
+        Ok(out) => {
+            let stdout = String::from_utf8_lossy(&out.stdout);
+            let stderr = String::from_utf8_lossy(&out.stderr);
+            let combined = format!("{stdout}{stderr}");
+
+            // Check if llvm-cov is missing
+            if combined.contains("cargo-llvm-cov not available") && !combined.contains("TOTAL") {
+                return format!(
+                    "**Coverage**\n\n`cargo-llvm-cov` is not installed.\n\nInstall it with:\n```\ncargo install cargo-llvm-cov\n```"
+                );
+            }
+
+            parse_coverage_output(&combined, out.status.success())
+        }
+    }
+}
+
+/// Parse the summary block from `script/test_coverage` output and format it.
+fn parse_coverage_output(output: &str, passed: bool) -> String {
+    let rust_cov = extract_line_value(output, "Rust line coverage:");
+    let frontend_cov = extract_line_value(output, "Frontend line coverage:");
+    let overall = extract_summary_field(output, "Overall:");
+    let threshold = extract_summary_field(output, "Threshold:");
+
+    let mut out = "**Coverage (fresh)**\n\n".to_string();
+
+    if let Some(r) = &rust_cov {
+        out.push_str(&format!("Rust:     {r}\n"));
+    }
+    if let Some(f) = &frontend_cov {
+        out.push_str(&format!("Frontend: {f}\n"));
+    }
+    if let Some(o) = &overall {
+        out.push_str(&format!("Overall:  {o}\n"));
+    }
+    if let Some(t) = &threshold {
+        out.push_str(&format!("Threshold: {t}\n"));
+    }
+
+    if rust_cov.is_none() && frontend_cov.is_none() && overall.is_none() {
+        // Could not parse — show raw output excerpt
+        let excerpt: String = output.lines().rev().take(10).collect::<Vec<_>>().into_iter().rev().collect::<Vec<_>>().join("\n");
+        return format!("**Coverage (fresh)**\n\n```\n{excerpt}\n```");
+    }
+
+    if passed {
+        out.push_str("\nPASS");
+    } else {
+        out.push_str("\nFAIL: coverage below threshold");
+    }
+
+    out
+}
+
+/// Extract a value from lines like `"Rust line coverage: 62.5%"`.
+fn extract_line_value(output: &str, prefix: &str) -> Option<String> {
+    output
+        .lines()
+        .find(|l| l.trim().starts_with(prefix))
+        .map(|l| l.trim()[prefix.len()..].trim().to_string())
+}
+
+/// Extract a value from the summary block: `"  Overall:  62.5%"`.
+fn extract_summary_field(output: &str, label: &str) -> Option<String> {
+    output
+        .lines()
+        .find(|l| l.trim().starts_with(label))
+        .map(|l| l.trim()[label.len()..].trim().to_string())
+}
+
+// ---------------------------------------------------------------------------
+// Tests
+// ---------------------------------------------------------------------------
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::agents::AgentPool;
+    use std::collections::HashSet;
+    use std::sync::{Arc, Mutex};
+
+    fn make_ctx<'a>(
+        agents: &'a Arc<AgentPool>,
+        ambient_rooms: &'a Arc<Mutex<HashSet<String>>>,
+        project_root: &'a std::path::Path,
+        args: &'a str,
+    ) -> super::super::CommandContext<'a> {
+        super::super::CommandContext {
+            bot_name: "Timmy",
+            args,
+            project_root,
+            agents,
+            ambient_rooms,
+            room_id: "!test:example.com",
+        }
+    }
+
+    fn test_agents() -> Arc<AgentPool> {
+        Arc::new(AgentPool::new_test(3000))
+    }
+
+    fn test_ambient() -> Arc<Mutex<HashSet<String>>> {
+        Arc::new(Mutex::new(HashSet::new()))
+    }
+
+    #[test]
+    fn coverage_command_is_registered() {
+        use super::super::commands;
+        let found = commands().iter().any(|c| c.name == "coverage");
+        assert!(found, "coverage command must be in the registry");
+    }
+
+    #[test]
+    fn coverage_command_appears_in_help() {
+        let result = super::super::tests::try_cmd_addressed(
+            "Timmy",
+            "@timmy:homeserver.local",
+            "@timmy help",
+        );
+        let output = result.unwrap();
+        assert!(
+            output.contains("coverage"),
+            "help should list coverage command: {output}"
+        );
+    }
+
+    #[test]
+    fn coverage_no_args_reads_baseline() {
+        let dir = tempfile::tempdir().expect("tempdir");
+        std::fs::write(dir.path().join(".coverage_baseline"), "72.5\n").unwrap();
+
+        let agents = test_agents();
+        let ambient = test_ambient();
+        let ctx = make_ctx(&agents, &ambient, dir.path(), "");
+        let output = handle_coverage(&ctx).unwrap();
+
+        assert!(
+            output.contains("72.5"),
+            "should report cached value from baseline: {output}"
+        );
+        assert!(
+            output.contains("cached"),
+            "response should indicate cached result: {output}"
+        );
+    }
+
+    #[test]
+    fn coverage_no_args_two_line_baseline() {
+        let dir = tempfile::tempdir().expect("tempdir");
+        std::fs::write(dir.path().join(".coverage_baseline"), "60.00\n65.21\n").unwrap();
+
+        let agents = test_agents();
+        let ambient = test_ambient();
+        let ctx = make_ctx(&agents, &ambient, dir.path(), "");
+        let output = handle_coverage(&ctx).unwrap();
+
+        assert!(
+            output.contains("60.00"),
+            "should report first baseline value: {output}"
+        );
+        assert!(
+            output.contains("65.21"),
+            "should report second baseline value: {output}"
+        );
+    }
+
+    #[test]
+    fn coverage_missing_baseline_reports_clearly() {
+        let dir = tempfile::tempdir().expect("tempdir");
+
+        let agents = test_agents();
+        let ambient = test_ambient();
+        let ctx = make_ctx(&agents, &ambient, dir.path(), "");
+        let output = handle_coverage(&ctx).unwrap();
+
+        assert!(
+            output.contains("No `.coverage_baseline`") || output.contains("coverage_baseline"),
+            "missing baseline should mention the file name: {output}"
+        );
+    }
+
+    #[test]
+    fn coverage_run_missing_script_reports_error() {
+        let dir = tempfile::tempdir().expect("tempdir");
+
+        let agents = test_agents();
+        let ambient = test_ambient();
+        let ctx = make_ctx(&agents, &ambient, dir.path(), "run");
+        let output = handle_coverage(&ctx).unwrap();
+
+        assert!(
+            output.contains("not found") || output.contains("script"),
+            "missing script should produce a clear error: {output}"
+        );
+    }
+
+    #[test]
+    fn coverage_unknown_arg_returns_usage() {
+        let dir = tempfile::tempdir().expect("tempdir");
+        let agents = test_agents();
+        let ambient = test_ambient();
+        let ctx = make_ctx(&agents, &ambient, dir.path(), "blah");
+        let output = handle_coverage(&ctx).unwrap();
+        assert!(
+            output.contains("Usage"),
+            "unknown arg should show usage: {output}"
+        );
+    }
+
+    #[test]
+    fn coverage_command_works_via_dispatch() {
+        let dir = tempfile::tempdir().expect("tempdir");
+        std::fs::write(dir.path().join(".coverage_baseline"), "55.0\n").unwrap();
+
+        let agents = test_agents();
+        let ambient = test_ambient();
+        let room_id = "!test:example.com".to_string();
+        let dispatch = super::super::CommandDispatch {
+            bot_name: "Timmy",
+            bot_user_id: "@timmy:homeserver.local",
+            project_root: dir.path(),
+            agents: &agents,
+            ambient_rooms: &ambient,
+            room_id: &room_id,
+        };
+        let result = super::super::try_handle_command(&dispatch, "@timmy coverage");
+        assert!(
+            result.is_some(),
+            "coverage command must respond via dispatch (not fall through to LLM)"
+        );
+    }
+
+    #[test]
+    fn parse_coverage_output_extracts_fields() {
+        let sample = "\
+Rust line coverage: 62.5%\n\
+Frontend line coverage: 70.0%\n\
+=== Coverage Summary ===\n\
+  Rust:     62.5%\n\
+  Frontend: 70.0%\n\
+  Overall:  66.25%\n\
+  Threshold: 60.00%\n\
+PASS: Coverage 66.25% meets threshold 60.00%\n\
+";
+        let result = parse_coverage_output(sample, true);
+        assert!(result.contains("62.5"), "should include Rust coverage: {result}");
+        assert!(result.contains("70.0"), "should include Frontend coverage: {result}");
+        assert!(result.contains("66.25"), "should include Overall coverage: {result}");
+        assert!(result.contains("PASS"), "should indicate PASS: {result}");
+    }
+
+    #[test]
+    fn extract_line_value_finds_rust_coverage() {
+        let output = "Rust line coverage: 55.3%\n";
+        let val = extract_line_value(output, "Rust line coverage:");
+        assert_eq!(val.as_deref(), Some("55.3%"));
+    }
+
+    #[test]
+    fn extract_summary_field_finds_overall() {
+        let output = "  Overall:  72.1%\n";
+        let val = extract_summary_field(output, "Overall:");
+        assert_eq!(val.as_deref(), Some("72.1%"));
+    }
+}
diff --git a/server/src/chat/commands/mod.rs b/server/src/chat/commands/mod.rs
index 9cb4cf59..28edae78 100644
--- a/server/src/chat/commands/mod.rs
+++ b/server/src/chat/commands/mod.rs
@@ -8,6 +8,7 @@
 mod ambient;
 mod assign;
 mod cost;
+mod coverage;
 mod git;
 mod help;
 pub(crate) mod loc;
@@ -118,6 +119,11 @@ pub fn commands() -> &'static [BotCommand] {
             description: "Show token spend: 24h total, top stories, breakdown by agent type, and all-time total",
             handler: cost::handle_cost,
         },
+        BotCommand {
+            name: "coverage",
+            description: "Show test coverage: cached baseline by default, or `coverage run` to rerun the full suite",
+            handler: coverage::handle_coverage,
+        },
         BotCommand {
             name: "loc",
             description: "Show top source files by line count: `loc` (top 10), `loc <N>`, or `loc <filepath>` for a specific file",