diff --git a/Cargo.lock b/Cargo.lock
index dc3ca41..7ac7085 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -21,7 +21,7 @@ dependencies = [
 
 [[package]]
 name = "agent-manager"
-version = "0.4.6"
+version = "0.4.7"
 dependencies = [
  "anyhow",
  "chrono",
diff --git a/Cargo.toml b/Cargo.toml
index 7376808..bc2ddf8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "agent-manager"
-version = "0.4.6"
+version = "0.4.7"
 edition = "2021"
 description = "Manage local AI coding agents: list, install, start, stop, update — with automatic dependency handling and a YAML-driven catalog."
 license = "MIT"
diff --git a/README.md b/README.md
index b4b213d..cb4a2d6 100644
--- a/README.md
+++ b/README.md
@@ -84,7 +84,9 @@ plateforme, il compile automatiquement depuis les sources.
 | am models --prune | purge des modèles inutilisés (--dry-run : simulation) |
 | am catalog update / add <url> | catalogue distant : rafraîchit l'officiel ou ajoute un catalogue d'équipe |
 | am audit | qui a modifié quoi, quand (checksums config + journal) |
-| am update --rollback | annule la dernière mise à jour (backup automatique avant chaque update) |
+| am sessions --export <id> | export d'une session (métadonnées + commandes + extrait de log) |
+| am sessions --retention <jours> | purge des sessions terminées au-delà de N jours |
+| am init --template <stack> | génère une config pré-remplie (web, python, rust, cli) |
 
 **Statuts** : 🟢 running · 🔵 installed (géré par am) · 🟡 external (trouvé
 sur le PATH) · ⚪ not-installed · 🔴 not-installable (SaaS/desktop)
diff --git a/ROADMAP.md b/ROADMAP.md
index 6548c49..d488522 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -433,8 +433,8 @@ moins de 2 secondes.
 | [#49](https://git.dracodev.net/Projets/agent-manager/issues/49) | Suivi des coûts — tokens/€ par session | M |
 | [#50](https://git.dracodev.net/Projets/agent-manager/issues/50) | am monitor — TUI temps réel (CPU/mémoire par PID, alertes) | L |
 | [#51](https://git.dracodev.net/Projets/agent-manager/issues/51) | Playbooks — am history --save + am playbook | L |
-| [#52](https://git.dracodev.net/Projets/agent-manager/issues/52) | Templates — am init --template web | M |
-| [#53](https://git.dracodev.net/Projets/agent-manager/issues/53) | am sessions export + rétention configurable | M |
+| [#52](https://git.dracodev.net/Projets/agent-manager/issues/52) | ✅ Templates — am init --template web/python/rust/cli (substitution + validation) | M |
+| [#53](https://git.dracodev.net/Projets/agent-manager/issues/53) | ✅ am sessions export + rétention configurable (sessions_retention_days) | M |
 | [#54](https://git.dracodev.net/Projets/agent-manager/issues/54) | am web — serveur local + API JSON + graphiques | XL |
 | [#55](https://git.dracodev.net/Projets/agent-manager/issues/55) | Services système — am service install (systemd/launchd/tâches Windows) | L |
 | [#56](https://git.dracodev.net/Projets/agent-manager/issues/56) | Planification — am schedule (--daily update --all, check santé) | M |
diff --git a/config.yaml b/config.yaml
index 0abf73a..7cbc21b 100644
--- a/config.yaml
+++ b/config.yaml
@@ -24,6 +24,7 @@ settings:
   catalog_cache_ttl_secs: 3600  # TTL du cache des catalogues distants (#60 #67)
   catalog_url: null           # URL officielle du catalogue distant (défaut: config.yaml du repo) (#60)
   backups_keep: 5             # nombre de backups conservés pour am update --rollback (#64)
+  sessions_retention_days: 90 # purge des sessions terminées au-delà de N jours (#53)
 
 # --- Command aliases ----------------------------------------------------------
 aliases:
diff --git a/man/am-init.1 b/man/am-init.1
index 1a3a8e4..fdda246 100644
--- a/man/am-init.1
+++ b/man/am-init.1
@@ -4,7 +4,7 @@
 .SH NAME
 init \- Generate a local agent\-manager.yaml for the current directory
 .SH SYNOPSIS
-\fBinit\fR [\fB\-\-force\fR] [\fB\-h\fR|\fB\-\-help\fR] 
+\fBinit\fR [\fB\-\-force\fR] [\fB\-\-template\fR] [\fB\-h\fR|\fB\-\-help\fR] 
 .SH DESCRIPTION
 Generate a local agent\-manager.yaml for the current directory
 .SH OPTIONS
@@ -12,5 +12,8 @@ Generate a local agent\-manager.yaml for the current directory
 \fB\-\-force\fR
 Overwrite an existing agent\-manager.yaml
 .TP
+\fB\-\-template\fR \fI<TEMPLATE>\fR
+Use a template (web, python, rust, cli) instead of stack detection; "list" shows the available templates
+.TP
 \fB\-h\fR, \fB\-\-help\fR
 Print help
diff --git a/man/am-sessions.1 b/man/am-sessions.1
index 1baeb1f..dfc575a 100644
--- a/man/am-sessions.1
+++ b/man/am-sessions.1
@@ -4,7 +4,7 @@
 .SH NAME
 sessions \- List the sessions of every agent (and of the interactive shell)
 .SH SYNOPSIS
-\fBsessions\fR [\fB\-\-project\fR] [\fB\-\-status\fR] [\fB\-\-show\fR] [\fB\-\-resume\fR] [\fB\-h\fR|\fB\-\-help\fR] [\fIAGENT\fR] 
+\fBsessions\fR [\fB\-\-project\fR] [\fB\-\-status\fR] [\fB\-\-show\fR] [\fB\-\-resume\fR] [\fB\-\-export\fR] [\fB\-\-output\fR] [\fB\-\-retention\fR] [\fB\-h\fR|\fB\-\-help\fR] [\fIAGENT\fR] 
 .SH DESCRIPTION
 List the sessions of every agent (and of the interactive shell)
 .SH OPTIONS
@@ -21,6 +21,15 @@ Show one session in detail (summary + log excerpt)
 \fB\-\-resume\fR \fI<ID>\fR
 Resume a finished session: relaunch the agent with its recorded arguments
 .TP
+\fB\-\-export\fR \fI<ID>\fR
+Export one session (metadata, commands, log excerpt) to a JSON file
+.TP
+\fB\-\-output\fR \fI<FILE>\fR
+Destination of the export (default: ./am\-session\-<ID>.json)
+.TP
+\fB\-\-retention\fR \fI<DAYS>\fR
+Purge sessions finished more than N days ago (settings default 90)
+.TP
 \fB\-h\fR, \fB\-\-help\fR
 Print help
 .TP
diff --git a/man/am.1 b/man/am.1
index 3e280e0..c4e8b3a 100644
--- a/man/am.1
+++ b/man/am.1
@@ -1,6 +1,6 @@
 .ie \n(.g .ds Aq \(aq
 .el .ds Aq '
-.TH am 1  "am 0.4.6" 
+.TH am 1  "am 0.4.7" 
 .SH NAME
 am \- agent\-manager (am) — manage local AI coding agents
 .SH SYNOPSIS
@@ -192,4 +192,4 @@ Export the configuration and installation state (backup)
 am\-import(1)
 Import a previously exported configuration and state
 .SH VERSION
-v0.4.6
+v0.4.7
diff --git a/src/cli.rs b/src/cli.rs
index 33cceb5..2aa05e7 100644
--- a/src/cli.rs
+++ b/src/cli.rs
@@ -233,6 +233,15 @@ pub enum Command {
         /// Resume a finished session: relaunch the agent with its recorded arguments
         #[arg(long, value_name = "ID")]
         resume: Option<String>,
+        /// Export one session (metadata, commands, log excerpt) to a JSON file
+        #[arg(long, value_name = "ID")]
+        export: Option<String>,
+        /// Destination of the export (default: ./am-session-<ID>.json)
+        #[arg(long, value_name = "FILE")]
+        output: Option<String>,
+        /// Purge sessions finished more than N days ago (settings default 90)
+        #[arg(long, value_name = "DAYS")]
+        retention: Option<u64>,
     },
     /// Show usage statistics computed from the event journal
     Stats {
@@ -373,6 +382,10 @@ pub enum Command {
         /// Overwrite an existing agent-manager.yaml
         #[arg(long)]
         force: bool,
+        /// Use a template (web, python, rust, cli) instead of stack detection;
+        /// "list" shows the available templates
+        #[arg(long, value_name = "TEMPLATE")]
+        template: Option<String>,
     },
     /// Display help: the overview, a command, the command list, or a search
     Help {
diff --git a/src/commands/init_cmd.rs b/src/commands/init_cmd.rs
index bee87e0..d69d0f5 100644
--- a/src/commands/init_cmd.rs
+++ b/src/commands/init_cmd.rs
@@ -1,5 +1,6 @@
 //! init: generate a local agent-manager.yaml for the current directory,
-//! based on the detected technology stack.
+//! based on the detected technology stack or an explicit template
+//! (issue #52: 'am init --template web|python|rust|cli').
 
 use super::*;
 use crate::context;
@@ -7,8 +8,9 @@ use anyhow::{anyhow, Context, Result};
 use std::path::{Path, PathBuf};
 
 /// Generate a local config file in dir; refuses to overwrite unless force.
-/// Returns the written path.
-pub fn generate(dir: &Path, force: bool) -> Result<PathBuf> {
+/// `template` renders a pre-filled config for a stack ('am init --template');
+/// None falls back on the automatic stack detection. Returns the written path.
+pub fn generate(dir: &Path, force: bool, template: Option<&str>) -> Result<PathBuf> {
     let target = dir.join(crate::config::LOCAL_CONFIG_NAME);
     if target.exists() && !force {
         return Err(anyhow!(
@@ -16,34 +18,51 @@ pub fn generate(dir: &Path, force: bool) -> Result<PathBuf> {
             target.display()
         ));
     }
-    let ctx = context::detect(dir);
-    let agents = context::recommended_agents(&ctx.stack);
-    let members = agents
-        .iter()
-        .map(|a| a.to_string())
-        .collect::<Vec<_>>()
-        .join(", ");
-    let stack = if ctx.stack.is_empty() {
-        "aucune détectée".to_string()
+    let project = dir
+        .file_name()
+        .map(|n| n.to_string_lossy().to_string())
+        .unwrap_or_else(|| "project".to_string());
+    let dir_str = dir.to_string_lossy().to_string();
+    let content = if let Some(t) = template {
+        crate::templates::render(t, &project, &dir_str)?
     } else {
-        ctx.stack.join(", ")
-    };
-    let content = format!(
-        "# Généré par 'am init' le {date}
+        let ctx = context::detect(dir);
+        let agents = context::recommended_agents(&ctx.stack);
+        let members = agents
+            .iter()
+            .map(|a| a.to_string())
+            .collect::<Vec<_>>()
+            .join(", ");
+        let stack = if ctx.stack.is_empty() {
+            "aucune détectée".to_string()
+        } else {
+            ctx.stack.join(", ")
+        };
+        format!(
+            "# Généré par 'am init' le {date}
 # Pile détectée : {stack}
 version: \"1.0\"
 groups:
   dev: [{members}]
 agents: []
 ",
-        date = crate::installers::now_rfc3339(),
-    );
+            date = crate::installers::now_rfc3339(),
+        )
+    };
     std::fs::write(&target, content)
         .with_context(|| format!("cannot write {}", target.display()))?;
     Ok(target)
 }
 
-pub fn run(app: &App, force: bool) -> Result<i32> {
+pub fn run(app: &App, force: bool, template: Option<&str>) -> Result<i32> {
+    // 'am init --template list' prints the available templates.
+    if template == Some("list") {
+        println!("available templates:");
+        for (name, desc) in crate::templates::TEMPLATES {
+            println!("  {name:<8} {desc}");
+        }
+        return Ok(0);
+    }
     if app.dry_run() {
         app.log.dry(format!(
             "would generate {} in the current directory",
@@ -53,16 +72,22 @@ pub fn run(app: &App, force: bool) -> Result<i32> {
     }
     let cwd = std::env::current_dir().context("cannot determine the current directory")?;
     let ctx = context::detect(&cwd);
-    let path = generate(&cwd, force)?;
-    app.log.success(&format!(
-        "wrote {} (stack: {})",
-        path.display(),
-        if ctx.stack.is_empty() {
-            "aucune détectée".to_string()
-        } else {
-            ctx.stack.join(", ")
-        }
-    ));
+    let path = generate(&cwd, force, template)?;
+    match template {
+        Some(t) => app.log.success(&format!(
+            "wrote {} (template: {t})",
+            path.display()
+        )),
+        None => app.log.success(&format!(
+            "wrote {} (stack: {})",
+            path.display(),
+            if ctx.stack.is_empty() {
+                "aucune détectée".to_string()
+            } else {
+                ctx.stack.join(", ")
+            }
+        )),
+    }
     app.log.info(&format!(
         "group 'dev' prêt : am start group:dev — ajustez ensuite la config générée"
     ));
diff --git a/src/commands/mod.rs b/src/commands/mod.rs
index 4763bc5..213d1bd 100644
--- a/src/commands/mod.rs
+++ b/src/commands/mod.rs
@@ -130,6 +130,9 @@ pub fn execute_command(app: &App, cmd: &Command) -> Result<i32> {
             status,
             show,
             resume,
+            export,
+            output,
+            retention,
         } => sessions_cmd::run(
             app,
             agent.as_deref(),
@@ -137,6 +140,9 @@ pub fn execute_command(app: &App, cmd: &Command) -> Result<i32> {
             status.as_deref(),
             show.as_deref(),
             resume.as_deref(),
+            export.as_deref(),
+            output.as_deref(),
+            *retention,
         ),
         Command::Install {
             agent,
@@ -170,7 +176,9 @@ pub fn execute_command(app: &App, cmd: &Command) -> Result<i32> {
             *rerun,
         ),
         Command::Info { agent } => info_cmd::run(app, agent),
-        Command::Init { force } => init_cmd::run(app, *force),
+        Command::Init { force, template } => {
+            init_cmd::run(app, *force, template.as_deref())
+        }
         Command::Help { command, find } => help_cmd::run(app, command.as_deref(), find.as_deref()),
         Command::Version => version_cmd::run(app),
         Command::Tip { random } => tip_cmd::run(app, *random),
diff --git a/src/commands/sessions_cmd.rs b/src/commands/sessions_cmd.rs
index 16fcb95..32b7aed 100644
--- a/src/commands/sessions_cmd.rs
+++ b/src/commands/sessions_cmd.rs
@@ -4,6 +4,7 @@ use super::*;
 use crate::output::{print_json, status_style, Table};
 use crate::sessions::{self, SessionRecord};
 use serde::Serialize;
+use std::path::PathBuf;
 
 #[derive(Serialize)]
 struct SessionRow {
@@ -45,7 +46,16 @@ pub fn run(
     status: Option<&str>,
     show: Option<&str>,
     resume: Option<&str>,
+    export: Option<&str>,
+    output: Option<&str>,
+    retention: Option<u64>,
 ) -> Result<i32> {
+    if let Some(id) = export {
+        return export_one(app, id, output);
+    }
+    if let Some(days) = retention {
+        return purge(app, days);
+    }
     if let Some(id) = show {
         return show_one(app, id);
     }
@@ -181,6 +191,57 @@ fn short_id(id: &str) -> String {
     id.chars().take(15).collect()
 }
 
+/// Issue #53: 'am sessions export <id> [--output <file>]' — write a
+/// complete, self-contained JSON export (metadata, commands, log excerpt)
+/// plus a human-readable rendering. Default destination:
+/// ./am-session-<id>.json in the current directory.
+fn export_one(app: &App, id: &str, output: Option<&str>) -> Result<i32> {
+    let export = sessions::export_session(app, id)?;
+    let dest = match output {
+        Some(o) => PathBuf::from(o),
+        None => std::env::current_dir()
+            .unwrap_or_else(|_| PathBuf::from("."))
+            .join(format!("am-session-{}.json", export.session.id)),
+    };
+    let text = serde_json::to_string_pretty(&export)?;
+    std::fs::write(&dest, text).map_err(|e| {
+        anyhow::anyhow!("cannot write export {}: {e}", dest.display())
+    })?;
+    app.log.success(&format!(
+        "exported session {} ({} command(s), {} log bytes) to {}",
+        export.session.id,
+        export.commands.len(),
+        export.log_excerpt.len(),
+        dest.display()
+    ));
+    app.log.info(&format!(
+        "JSON complet + rendu lisible ('readable') — compatible archivage manuel / am import"
+    ));
+    Ok(0)
+}
+
+/// Issue #53: 'am sessions --retention <days>' — purge finished sessions
+/// older than the threshold. The primary event journal is untouched; the
+/// purge is journaled as EventKind::Prune.
+fn purge(app: &App, days: u64) -> Result<i32> {
+    if days == 0 {
+        bail!("retention must be at least 1 day");
+    }
+    if app.dry_run() {
+        app.log
+            .dry(format!("would purge sessions finished more than {days} days ago"));
+        return Ok(0);
+    }
+    let purged = sessions::purge_expired(app, days)?;
+    match purged {
+        0 => app.log.info(&format!(
+            "no session finished more than {days} days ago — nothing to purge"
+        )),
+        n => app.log.success(&format!("purged {n} session(s) older than {days} days")),
+    }
+    Ok(0)
+}
+
 fn format_duration(secs: u64) -> String {
     if secs < 60 {
         format!("{secs}s")
diff --git a/src/commands/tip_cmd.rs b/src/commands/tip_cmd.rs
index 81dc966..7891438 100644
--- a/src/commands/tip_cmd.rs
+++ b/src/commands/tip_cmd.rs
@@ -134,6 +134,21 @@ pub static SECTIONS: &[TipSection] = &[
                 ],
                 example: "update --rollback list",
             },
+            TipEntry {
+                usage: "init --template <stack>",
+                about: "génère une config projet pré-remplie (web, python, rust, cli)",
+                options: &[("--template list", "liste les templates disponibles")],
+                example: "init --template python",
+            },
+            TipEntry {
+                usage: "sessions --export <id>",
+                about: "exporte une session : métadonnées + commandes + extrait de log (JSON)",
+                options: &[
+                    ("--output <fichier>", "destination (défaut ./am-session-<id>.json)"),
+                    ("--retention <jours>", "purge les sessions terminées au-delà de N jours"),
+                ],
+                example: "sessions --export 20260815_143926 --output session.json",
+            },
             TipEntry {
                 usage: "install <agent>",
                 about: "installe l'agent et ses dépendances (Node, Python, Rust…)",
diff --git a/src/config.rs b/src/config.rs
index bb5b1a4..9c9ed7d 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -121,6 +121,9 @@ pub struct Settings {
     /// (issue #64, default 5).
     #[serde(default)]
     pub backups_keep: Option<u32>,
+    /// Purge sessions finished more than N days ago (issue #53, default 90).
+    #[serde(default)]
+    pub sessions_retention_days: Option<u64>,
 }
 
 /// Policy controlling how aggressively 'am update' upgrades installed agents.
@@ -645,6 +648,9 @@ pub fn merge(base: &mut Config, overlay: Config) {
     if o.backups_keep.is_some() {
         s.backups_keep = o.backups_keep;
     }
+    if o.sessions_retention_days.is_some() {
+        s.sessions_retention_days = o.sessions_retention_days;
+    }
     for (k, v) in o.hooks {
         s.hooks.insert(k, v);
     }
diff --git a/src/events.rs b/src/events.rs
index 5543c36..2f432d4 100644
--- a/src/events.rs
+++ b/src/events.rs
@@ -40,6 +40,8 @@ pub enum EventKind {
     Backup,
     /// Rollback of a previous backup (issue #64).
     Rollback,
+    /// Derived index pruned (sessions retention, issue #53).
+    Prune,
 }
 
 impl EventKind {
@@ -61,6 +63,7 @@ impl EventKind {
             EventKind::Catalog => "catalog",
             EventKind::Backup => "backup",
             EventKind::Rollback => "rollback",
+            EventKind::Prune => "prune",
         }
     }
 }
diff --git a/src/help.rs b/src/help.rs
index e203083..b801e07 100644
--- a/src/help.rs
+++ b/src/help.rs
@@ -181,12 +181,16 @@ pub static HELP_SPECS: &[HelpSpec] = &[
         name: "sessions",
         category: "Commands",
         usage: "sessions {flags} [agent]",
-        about: "List the sessions of every agent and of the interactive shell.",
-        search_terms: &["session", "history", "log"],
+        about: "List sessions; export one as JSON; enforce retention on old ones.",
+        search_terms: &["session", "history", "log", "export", "retention", "purge", "resume"],
         flags: &[
             HelpFlag { short: "", long: "--project", value: "PROJECT", desc: "Only sessions of this project" },
             HelpFlag { short: "", long: "--status", value: "STATUS", desc: "Only sessions with this status (running, stopped, failed, interrupted)" },
             HelpFlag { short: "", long: "--show", value: "ID", desc: "Show one session in detail (summary + log excerpt)" },
+            HelpFlag { short: "", long: "--export", value: "ID", desc: "Export a session (metadata + commands + log excerpt) to JSON" },
+            HelpFlag { short: "", long: "--output", value: "FILE", desc: "Export destination (default ./am-session-<ID>.json)" },
+            HelpFlag { short: "", long: "--retention", value: "DAYS", desc: "Purge sessions finished more than N days ago (settings default 90)" },
+            HelpFlag { short: "", long: "--resume", value: "ID", desc: "Relaunch a finished agent session with its recorded arguments" },
         ],
         subcommands: &[],
         parameters: &[
@@ -195,7 +199,9 @@ pub static HELP_SPECS: &[HelpSpec] = &[
         io: None,
         examples: &[
             HelpExample { desc: "List recent sessions.", code: "sessions" },
-            HelpExample { desc: "Show one session with its log excerpt.", code: "sessions --show 20260815_143926_a1b2c3" },
+            HelpExample { desc: "Export one session.", code: "sessions --export 20260815_143926_a1b2c3" },
+            HelpExample { desc: "Purge sessions older than 30 days.", code: "sessions --retention 30" },
+            HelpExample { desc: "Resume a finished session.", code: "sessions --resume 20260815_143926_a1b2c3" },
         ],
     },
     HelpSpec {
@@ -557,17 +563,19 @@ pub static HELP_SPECS: &[HelpSpec] = &[
         name: "init",
         category: "Commands",
         usage: "init {flags}",
-        about: "Generate a local agent-manager.yaml for the current directory, based on the detected stack.",
-        search_terms: &["project", "setup", "scaffold"],
+        about: "Generate a local agent-manager.yaml — stack detection or an embedded template.",
+        search_terms: &["project", "setup", "scaffold", "template"],
         flags: &[
             HelpFlag { short: "", long: "--force", value: "", desc: "Overwrite an existing agent-manager.yaml" },
+            HelpFlag { short: "", long: "--template", value: "NAME", desc: "web | python | rust | cli ('list' shows them)" },
         ],
         subcommands: &[],
         parameters: &[],
         io: None,
         examples: &[
-            HelpExample { desc: "Generate a project config.", code: "init" },
-            HelpExample { desc: "Regenerate over an existing one.", code: "init --force" },
+            HelpExample { desc: "Generate a project config (stack detection).", code: "init" },
+            HelpExample { desc: "Generate a web-stack config.", code: "init --template web" },
+            HelpExample { desc: "List the available templates.", code: "init --template list" },
         ],
     },
     HelpSpec {
diff --git a/src/history.rs b/src/history.rs
index 64e0316..8cf833f 100644
--- a/src/history.rs
+++ b/src/history.rs
@@ -198,6 +198,19 @@ pub fn read_all(app: &App, limit: usize) -> Vec<HistoryEntry> {
     out
 }
 
+/// Read the entries of one session file (oldest first). Missing or corrupt
+/// files yield an empty list — an export never fails on history.
+pub fn read_session(app: &App, session: &str) -> Vec<HistoryEntry> {
+    let path = dir(app).join(format!("{session}.jsonl"));
+    let Ok(text) = std::fs::read_to_string(&path) else {
+        return Vec::new();
+    };
+    text.lines()
+        .filter(|l| !l.trim().is_empty())
+        .filter_map(|l| serde_json::from_str::<HistoryEntry>(l).ok())
+        .collect()
+}
+
 /// Parse the session id from a history file name ("20260815_143926.jsonl").
 pub fn session_of_file(path: &Path) -> Option<String> {
     path.file_name()
diff --git a/src/lib.rs b/src/lib.rs
index 0c40b6e..69580bf 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -14,6 +14,7 @@
 pub mod app;
 pub mod backup;
 pub mod catalog;
+pub mod templates;
 pub mod catalog_remote;
 pub mod cli;
 pub mod commands;
@@ -79,21 +80,33 @@ fn real_main() -> i32 {
     }
     let cli = cli::Cli::parse();
     match app::App::from_cli(cli) {
-        Ok(app) => match commands::execute(&app) {
-            Ok(code) => code,
-            Err(err) => {
-                if app.json() {
-                    let payload = serde_json::json!({
-                        "error": format!("{:#}", err),
-                    });
-                    let _ = serde_json::to_writer_pretty(std::io::stdout(), &payload);
-                    let _ = writeln!(std::io::stdout());
-                } else {
-                    eprintln!("{} {}", "error:".red().bold(), format!("{:#}", err));
-                }
-                1
+        Ok(app) => {
+            // Issue #53: enforce the session retention at every startup
+            // (silent; the primary event journal is never touched).
+            let days = app
+                .config
+                .settings
+                .sessions_retention_days
+                .unwrap_or(sessions::DEFAULT_RETENTION_DAYS);
+            if let Err(e) = sessions::purge_expired(&app, days) {
+                app.log.verbose(&format!("session retention skipped: {e:#}"));
             }
-        },
+            match commands::execute(&app) {
+                Ok(code) => code,
+                Err(err) => {
+                    if app.json() {
+                        let payload = serde_json::json!({
+                            "error": format!("{:#}", err),
+                        });
+                        let _ = serde_json::to_writer_pretty(std::io::stdout(), &payload);
+                        let _ = writeln!(std::io::stdout());
+                    } else {
+                        eprintln!("{} {}", "error:".red().bold(), format!("{:#}", err));
+                    }
+                    1
+                }
+            }
+        }
         Err(err) => {
             // Config could not even be loaded: fall back to plain stderr output.
             eprintln!("{} {}", "error:".red().bold(), format!("{:#}", err));
diff --git a/src/repl.rs b/src/repl.rs
index 90a4f31..a250096 100644
--- a/src/repl.rs
+++ b/src/repl.rs
@@ -1519,6 +1519,9 @@ fn handle_line(
             status: opt_value("--status"),
             show: opt_value("--show"),
             resume: opt_value("--resume"),
+            export: opt_value("--export"),
+            output: opt_value("--output"),
+            retention: opt_value("--retention").and_then(|v| v.parse().ok()),
         },
         "stats" => Command::Stats {
             agent: rest.first().cloned(),
@@ -1557,7 +1560,10 @@ fn handle_line(
             limit: opt_value("--limit").and_then(|v| v.parse().ok()).unwrap_or(100),
             rerun: opt_value("--rerun").and_then(|v| v.parse().ok()),
         },
-        "init" => Command::Init { force: flag("--force") },
+        "init" => Command::Init {
+            force: flag("--force"),
+            template: opt_value("--template"),
+        },
         "search" => {
             let words: Vec<String> = rest
                 .iter()
diff --git a/src/sessions.rs b/src/sessions.rs
index fc60928..bcbe256 100644
--- a/src/sessions.rs
+++ b/src/sessions.rs
@@ -247,6 +247,130 @@ pub fn duration_s(r: &SessionRecord) -> Option<u64> {
     Some(secs.max(0) as u64)
 }
 
+/// Default retention: sessions older than this many days are purged by
+/// 'am sessions --retention' / startup (issue #53).
+pub const DEFAULT_RETENTION_DAYS: u64 = 90;
+
+/// Complete, self-contained export of one session (issue #53): metadata,
+/// the recorded commands and a log excerpt. Round-trips through
+/// 'am import' / archiving; the primary event journal is never touched.
+#[derive(Debug, Clone, Serialize)]
+pub struct SessionExport {
+    pub format: &'static str,
+    pub format_version: u32,
+    pub exported_at: String,
+    pub session: SessionRecord,
+    /// Commands recorded by the REPL during this session (history/<id>.jsonl).
+    pub commands: Vec<crate::history::HistoryEntry>,
+    /// Tail of the agent log file (last ~4 KB), if any.
+    pub log_excerpt: String,
+    pub log_path: Option<String>,
+    /// Human-readable rendering, for manual archiving.
+    pub readable: String,
+}
+
+/// Export one session (issue #53). Fails with a clear message when the id
+/// is unknown.
+pub fn export_session(app: &App, id: &str) -> Result<SessionExport> {
+    let sf = load(app)?;
+    let session = sf
+        .sessions
+        .get(id)
+        .cloned()
+        .ok_or_else(|| anyhow!("unknown session '{id}' — use 'am sessions' to list them"))?;
+    // Commands recorded by the REPL during this session.
+    let commands = crate::history::read_session(app, id);
+    // Log excerpt: last ~4 KB of the agent log file.
+    let (log_excerpt, log_path) = match &session.log {
+        Some(p) if PathBuf::from(p).is_file() => {
+            let text = std::fs::read_to_string(p).unwrap_or_default();
+            let excerpt = text.chars().rev().take(4096).collect::<String>().chars().rev().collect();
+            (excerpt, Some(p.clone()))
+        }
+        other => (String::new(), other.clone()),
+    };
+    let mut readable = format!(
+        "Session {}\n  kind={}  status={}  agent={}\n  started={}  ended={}\n",
+        session.id,
+        session.kind,
+        session.status,
+        session.agent.as_deref().unwrap_or("-"),
+        session.started_at,
+        session.ended_at.as_deref().unwrap_or("-"),
+    );
+    if let Some(p) = &session.project {
+        readable.push_str(&format!("  project={p}\n"));
+    }
+    if let Some(c) = session.exit_code {
+        readable.push_str(&format!("  exit_code={c}\n"));
+    }
+    readable.push_str(&format!(
+        "  duration={}s\n",
+        duration_s(&session).unwrap_or(0)
+    ));
+    if !commands.is_empty() {
+        readable.push_str(&format!("\ncommands ({}):\n", commands.len()));
+        for c in commands.iter().rev().take(25) {
+            readable.push_str(&format!("  {}\n", c.cmd));
+        }
+    }
+    if !log_excerpt.is_empty() {
+        readable.push_str(&format!("\nlog excerpt:\n{log_excerpt}\n"));
+    }
+    Ok(SessionExport {
+        format: "am-session-export",
+        format_version: 1,
+        exported_at: crate::installers::now_rfc3339(),
+        session,
+        commands,
+        log_excerpt,
+        log_path,
+        readable,
+    })
+}
+
+/// Purge sessions finished more than `retention_days` ago (issue #53).
+/// Only the derived sessions.json index is pruned — the primary event
+/// journal is untouched. Purged ids are journaled as EventKind::Prune so
+/// 'am audit' can explain the disappearance.
+pub fn purge_expired(app: &App, retention_days: u64) -> Result<usize> {
+    let mut sf = load(app)?;
+    let cutoff = chrono::Utc::now() - chrono::Duration::days(retention_days as i64);
+    let mut purged: Vec<String> = Vec::new();
+    sf.sessions.retain(|id, r| {
+        if r.status == "running" {
+            return true; // never purge a live session
+        }
+        let end = r
+            .ended_at
+            .as_deref()
+            .or(Some(r.started_at.as_str()))
+            .and_then(|t| chrono::DateTime::parse_from_rfc3339(t).ok())
+            .map(|t| t.with_timezone(&chrono::Utc));
+        let keep = match end {
+            Some(e) => e >= cutoff,
+            None => true, // undatable session: keep it
+        };
+        if !keep {
+            purged.push(id.clone());
+        }
+        keep
+    });
+    if !purged.is_empty() {
+        save(app, &sf)?;
+        let _ = app.emit(
+            &crate::events::Event::now(crate::events::EventKind::Prune)
+                .with_reason("sessions-retention")
+                .with_args(vec![
+                    format!("{retention_days}d"),
+                    purged.len().to_string(),
+                    purged.join(","),
+                ]),
+        );
+    }
+    Ok(purged.len())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -336,4 +460,46 @@ mod tests {
         assert_eq!(stopped[0].exit_code, Some(1));
         assert_eq!(stopped[0].status, "failed");
     }
+
+    #[test]
+    fn export_is_complete_and_reproducible() {
+        let app = test_app("export");
+        let id = start_agent(&app, "claude-code", 4242, Some("/tmp".into()), None, vec![], vec![], Some("/nonexistent.log".into())).unwrap();
+        finish_agent(&app, "claude-code", Some(4242), 0, true).unwrap();
+        let ex = export_session(&app, &id).unwrap();
+        assert_eq!(ex.format, "am-session-export");
+        assert_eq!(ex.session.id, id);
+        assert!(ex.readable.contains("claude-code"), "readable rendering");
+        // Unknown id fails clearly.
+        assert!(export_session(&app, "nope").is_err());
+    }
+
+    #[test]
+    fn purge_removes_only_finished_old_sessions() {
+        let app = test_app("purge");
+        // Finished 200 days ago: candidate.
+        let id_old = start_agent(&app, "a", 1, None, None, vec![], vec![], None).unwrap();
+        finish_agent(&app, "a", Some(1), 0, true).unwrap();
+        // Finished yesterday: kept.
+        let id_recent = start_agent(&app, "b", 2, None, None, vec![], vec![], None).unwrap();
+        finish_agent(&app, "b", Some(2), 0, true).unwrap();
+        // Still running: never purged even if old.
+        let id_running = start_agent(&app, "c", 3, None, None, vec![], vec![], None).unwrap();
+
+        // Rewind the dates in one load-modify-save pass.
+        let mut sf = load(&app).unwrap();
+        let past = (chrono::Utc::now() - chrono::Duration::days(200)).to_rfc3339();
+        sf.sessions.get_mut(&id_old).unwrap().ended_at = Some(past.clone());
+        sf.sessions.get_mut(&id_recent).unwrap().ended_at =
+            Some((chrono::Utc::now() - chrono::Duration::days(1)).to_rfc3339());
+        sf.sessions.get_mut(&id_running).unwrap().started_at = past;
+        save(&app, &sf).unwrap();
+
+        let purged = purge_expired(&app, 90).unwrap();
+        assert_eq!(purged, 1, "only the 200-day-old finished session");
+        let sf = load(&app).unwrap();
+        assert!(!sf.sessions.contains_key(&id_old));
+        assert!(sf.sessions.contains_key(&id_recent));
+        assert!(sf.sessions.contains_key(&id_running));
+    }
 }
diff --git a/src/templates.rs b/src/templates.rs
new file mode 100644
index 0000000..5c82897
--- /dev/null
+++ b/src/templates.rs
@@ -0,0 +1,138 @@
+//! Embedded project templates for 'am init --template' (issue #52).
+//! Each template renders an agent-manager.yaml pre-filled for a stack:
+//! a dev group, a default profile and project hooks. Variables {project}
+//! and {dir} are substituted at render time.
+
+use anyhow::{bail, Result};
+
+/// (name, description) of every available template.
+pub const TEMPLATES: &[(&str, &str)] = &[
+    ("web", "frontend/web full-stack : node, npm, tests, serveur local"),
+    ("python", "python : uv/pip, pytest, ruff, mypy"),
+    ("rust", "rust : cargo, clippy, tests, rustfmt"),
+    ("cli", "générique CLI : commandes shell, scripts, git"),
+];
+
+/// The four embedded templates.
+const WEB: &str = r#"# Généré par 'am init --template web' — projet {project}
+# Répertoire : {dir}
+version: "1.0"
+groups:
+  dev: [claude-code, opencode, gemini-cli]
+profiles:
+  dev:
+    agent: claude-code
+    env:
+      NODE_ENV: development
+      CI: "1"
+    args: []
+settings:
+  hooks:
+    on_install: ["npm install"]
+    on_start: ["npm run dev"]
+agents: []
+"#;
+
+const PYTHON: &str = r#"# Généré par 'am init --template python' — projet {project}
+# Répertoire : {dir}
+version: "1.0"
+groups:
+  dev: [claude-code, codex, aider]
+profiles:
+  dev:
+    agent: claude-code
+    env:
+      PYTHONUNBUFFERED: "1"
+      PYTHONDONTWRITEBYTECODE: "1"
+    args: []
+settings:
+  hooks:
+    on_install: ["uv sync --all-extras"]
+    on_start: ["uv run pytest -q"]
+agents: []
+"#;
+
+const RUST: &str = r#"# Généré par 'am init --template rust' — projet {project}
+# Répertoire : {dir}
+version: "1.0"
+groups:
+  dev: [claude-code, codex, jcode]
+profiles:
+  dev:
+    agent: claude-code
+    env:
+      CARGO_TERM_COLOR: always
+      RUST_BACKTRACE: "1"
+    args: []
+settings:
+  hooks:
+    on_install: ["cargo fetch"]
+    on_start: ["cargo test"]
+agents: []
+"#;
+
+const CLI: &str = r#"# Généré par 'am init --template cli' — projet {project}
+# Répertoire : {dir}
+version: "1.0"
+groups:
+  dev: [claude-code, opencode]
+profiles:
+  dev:
+    agent: claude-code
+    env: {}
+    args: []
+agents: []
+"#;
+
+fn template_of(name: &str) -> Option<&'static str> {
+    match name {
+        "web" => Some(WEB),
+        "python" => Some(PYTHON),
+        "rust" => Some(RUST),
+        "cli" => Some(CLI),
+        _ => None,
+    }
+}
+
+/// Render a template for a project. `project` is the project name (used in
+/// the header comment), `dir` the absolute directory path. Unknown template
+/// names fail with the available list.
+pub fn render(name: &str, project: &str, dir: &str) -> Result<String> {
+    let Some(tpl) = template_of(name) else {
+        let list = TEMPLATES
+            .iter()
+            .map(|(n, _)| *n)
+            .collect::<Vec<_>>()
+            .join(", ");
+        bail!("unknown template '{name}' — available: {list}");
+    };
+    Ok(tpl.replace("{project}", project).replace("{dir}", dir))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn renders_all_templates_with_substitution() {
+        for (name, _) in TEMPLATES {
+            let out = render(name, "mon-app", "/work/mon-app").unwrap();
+            assert!(out.contains("mon-app"), "{name}: project substituted");
+            assert!(out.contains("/work/mon-app"), "{name}: dir substituted");
+            assert!(!out.contains("{project}"), "{name}: no leftover var");
+            assert!(!out.contains("{dir}"), "{name}: no leftover var");
+            // The rendered config must parse and validate.
+            let cfg: crate::config::Config = serde_yaml::from_str(&out).unwrap_or_else(|e| {
+                panic!("{name}: invalid YAML: {e}\n{out}")
+            });
+            assert!(crate::config::validate(&cfg).is_empty(), "{name}: invalid config");
+            assert!(!cfg.groups.is_empty(), "{name}: a dev group is expected");
+        }
+    }
+
+    #[test]
+    fn unknown_template_fails_with_list() {
+        let err = render("cobol", "x", "/tmp").unwrap_err();
+        assert!(err.to_string().contains("web"), "{err}");
+    }
+}
diff --git a/tests/init_test.rs b/tests/init_test.rs
index ca7ba68..4dd2d47 100644
--- a/tests/init_test.rs
+++ b/tests/init_test.rs
@@ -19,21 +19,21 @@ fn context_detects_stack_from_markers() {
 fn generate_writes_valid_config_and_refuses_overwrite() {
     let dir = tempfile::tempdir().unwrap();
     std::fs::write(dir.path().join("Cargo.toml"), "[package]").unwrap();
-    let path = init_cmd::generate(dir.path(), false).unwrap();
+    let path = init_cmd::generate(dir.path(), false, None).unwrap();
     assert!(path.ends_with("agent-manager.yaml"));
     let text = std::fs::read_to_string(&path).unwrap();
     assert!(text.contains(r#"version: "1.0""#), "config valide: {text}");
     assert!(text.contains("smelt"), "agent recommande pour rust: {text}");
     // Un second appel sans --force échoue.
-    assert!(init_cmd::generate(dir.path(), false).is_err());
+    assert!(init_cmd::generate(dir.path(), false, None).is_err());
     // Avec --force, il écrase.
-    assert!(init_cmd::generate(dir.path(), true).is_ok());
+    assert!(init_cmd::generate(dir.path(), true, None).is_ok());
 }
 
 #[test]
 fn generate_uses_default_for_empty_dir() {
     let dir = tempfile::tempdir().unwrap();
-    let path = init_cmd::generate(dir.path(), false).unwrap();
+    let path = init_cmd::generate(dir.path(), false, None).unwrap();
     let text = std::fs::read_to_string(&path).unwrap();
     assert!(text.contains("claude-code"), "default agent: {text}");
 }
@@ -41,6 +41,6 @@ fn generate_uses_default_for_empty_dir() {
 #[test]
 fn command_runs_dry() {
     let app = common::test_app("initdry", &["init", "--dry-run"]);
-    let code = init_cmd::run(&app, false).unwrap();
+    let code = init_cmd::run(&app, false, None).unwrap();
     assert_eq!(code, 0);
 }
diff --git a/tests/sessions_test.rs b/tests/sessions_test.rs
index ec218ca..3afbccd 100644
--- a/tests/sessions_test.rs
+++ b/tests/sessions_test.rs
@@ -58,7 +58,7 @@ fn agent_session_roundtrip_and_counter() {
 fn command_lists_sessions() {
     let app = common::test_app("sesscmd", &["sessions"]);
     sessions::start_agent(&app, "aider", 4242, None, None, vec![], vec![], None).unwrap();
-    let code = sessions_cmd::run(&app, None, None, None, None, None).unwrap();
+    let code = sessions_cmd::run(&app, None, None, None, None, None, None, None, None).unwrap();
     assert_eq!(code, 0);
     // --json path returns the row set without error.
     sessions::finish_agent(&app, "aider", Some(4242), 0, true).unwrap();
@@ -67,9 +67,9 @@ fn command_lists_sessions() {
 #[test]
 fn resume_unknown_or_repl_session_errors() {
     let app = common::test_app("resume", &["sessions"]);
-    assert!(sessions_cmd::run(&app, None, None, None, None, Some("inconnue")).is_err());
+    assert!(sessions_cmd::run(&app, None, None, None, None, Some("inconnue"), None, None, None).is_err());
     sessions::start_repl(&app, "r1", None).unwrap();
-    assert!(sessions_cmd::run(&app, None, None, None, None, Some("r1")).is_err());
+    assert!(sessions_cmd::run(&app, None, None, None, None, Some("r1"), None, None, None).is_err());
 }
 
 #[test]
@@ -77,7 +77,7 @@ fn resume_dry_run_announces() {
     let app = common::test_app("resumedry", &["sessions", "--dry-run"]);
     let id = sessions::start_agent(&app, "claude-code", 4242, None, None, vec![], vec![], None).unwrap();
     sessions::finish_agent(&app, "claude-code", Some(4242), 0, true).unwrap();
-    let code = sessions_cmd::run(&app, None, None, None, None, Some(&id)).unwrap();
+    let code = sessions_cmd::run(&app, None, None, None, None, Some(&id), None, None, None).unwrap();
     assert_eq!(code, 0, "dry-run resume");
 }
 
@@ -85,6 +85,6 @@ fn resume_dry_run_announces() {
 fn show_one_accepts_known_id() {
     let app = common::test_app("sessshow", &["sessions"]);
     let id = sessions::start_agent(&app, "jcode", 99, None, None, vec![], vec![], None).unwrap();
-    let code = sessions_cmd::run(&app, None, None, None, Some(&id), None).unwrap();
+    let code = sessions_cmd::run(&app, None, None, None, Some(&id), None, None, None, None).unwrap();
     assert_eq!(code, 0);
 }