model/context: move context window config to host-level hive-c0re.nix

hive-c0re/src/actions.rs

@@ -91,6 +91,7 @@ pub async fn approve(coord: Arc<Coordinator>, id: i64) -> Result<()> {
                     &notes_dir,
                     coord_bg.dashboard_port,
                     &coord_bg.operator_pronouns,
+                    &coord_bg.context_window_tokens,
                 )
                 .await;
                 drop(guard);
@@ -415,6 +416,7 @@ async fn sync_meta_after_lifecycle(coord: &Coordinator) -> Result<()> {
         &coord.hyperhive_flake,
         coord.dashboard_port,
         &coord.operator_pronouns,
+        &coord.context_window_tokens,
         &agents,
     )
     .await

hive-c0re/src/auto_update.rs

@@ -73,6 +73,7 @@ pub async fn rebuild_agent(coord: &Arc<Coordinator>, name: &str, current_rev: &s
         &notes_dir,
         coord.dashboard_port,
         &coord.operator_pronouns,
+        &coord.context_window_tokens,
     )
     .await;
     drop(guard);
@@ -160,6 +161,7 @@ pub async fn ensure_manager(coord: &Arc<Coordinator>) -> Result<()> {
         &notes_dir,
         coord.dashboard_port,
         &coord.operator_pronouns,
+        &coord.context_window_tokens,
     )
     .await?;
     if let Some(rev) = current_rev {

hive-c0re/src/coordinator.rs

@@ -51,6 +51,13 @@ pub struct Coordinator {
     /// meta flake); the harness substitutes it into the agent /
     /// manager system prompt at boot.
     pub operator_pronouns: String,
+    /// Per-model context-window sizes in tokens. Set via the host-level
+    /// `services.hive-c0re.contextWindowTokens` NixOS option; injected
+    /// into each container as `HIVE_CONTEXT_WINDOW_TOKENS_<KEY_UPPER>`
+    /// by the meta flake renderer. The harness uses these to derive
+    /// compaction / auto-reset watermarks and exposes the active value
+    /// on `/api/state` as `context_window_tokens`.
+    pub context_window_tokens: std::collections::HashMap<String, u64>,
     agents: Mutex<HashMap<String, AgentSocket>>,
     /// Agents whose lifecycle action (currently just spawn) is in flight.
     /// Read by the dashboard to render a spinner; cleared when the action
@@ -139,6 +146,7 @@ impl Coordinator {
         hyperhive_flake: String,
         dashboard_port: u16,
         operator_pronouns: String,
+        context_window_tokens: std::collections::HashMap<String, u64>,
     ) -> Result<Self> {
         let broker = Broker::open(db_path).context("open broker")?;
         let approvals = Approvals::open(db_path).context("open approvals")?;
@@ -152,6 +160,7 @@ impl Coordinator {
             hyperhive_flake,
             dashboard_port,
             operator_pronouns,
+            context_window_tokens,
             agents: Mutex::new(HashMap::new()),
             transient: Mutex::new(HashMap::new()),
             dashboard_events,

hive-c0re/src/lifecycle.rs

@@ -138,6 +138,7 @@ pub async fn spawn(
     notes_dir: &Path,
     dashboard_port: u16,
     operator_pronouns: &str,
+    context_window_tokens: &std::collections::HashMap<String, u64>,
 ) -> Result<()> {
     validate(name)?;
     if let Some(other) = port_collision(name).await {
@@ -154,7 +155,7 @@ pub async fn spawn(
     // before `nixos-container create` so the `--flake meta#<name>`
     // ref resolves.
     let agents = agents_after_spawn(name).await?;
-    crate::meta::sync_agents(hyperhive_flake, dashboard_port, operator_pronouns, &agents).await?;
+    crate::meta::sync_agents(hyperhive_flake, dashboard_port, operator_pronouns, context_window_tokens, &agents).await?;
     let container = container_name(name);
     let flake_ref = format!("{}#{name}", crate::meta::meta_dir().display());
     run(&["create", &container, "--flake", &flake_ref]).await?;
@@ -273,6 +274,7 @@ pub async fn rebuild(
     notes_dir: &Path,
     dashboard_port: u16,
     operator_pronouns: &str,
+    context_window_tokens: &std::collections::HashMap<String, u64>,
 ) -> Result<()> {
     // Sync the meta flake (idempotent — no-op when the rendered
     // flake matches disk) so a manual rebuild from the dashboard
@@ -280,7 +282,7 @@ pub async fn rebuild(
     // got added directly via `nixos-container create` outside
     // hive-c0re).
     let agents = agents_for_meta(None).await?;
-    crate::meta::sync_agents(hyperhive_flake, dashboard_port, operator_pronouns, &agents).await?;
+    crate::meta::sync_agents(hyperhive_flake, dashboard_port, operator_pronouns, context_window_tokens, &agents).await?;
     // Then bump just this agent's input — picks up whatever
     // `applied/<n>/main` currently points at (deployed/<latest>).
     // Commits the lock if it changed.

hive-c0re/src/main.rs

@@ -62,6 +62,12 @@ enum Cmd {
         /// system prompt can mention them. Default: `she/her`.
         #[arg(long, default_value = "she/her")]
         operator_pronouns: String,
+        /// Per-model context-window sizes, as JSON object mapping model-family
+        /// short name to token count. Threaded into each container as
+        /// `HIVE_CONTEXT_WINDOW_TOKENS_<KEY_UPPER>` env vars. Set via the
+        /// `services.hive-c0re.contextWindowTokens` NixOS option.
+        #[arg(long, default_value = r#"{"haiku":200000,"sonnet":1000000,"opus":1000000}"#)]
+        context_window_tokens: String,
     },
     /// Spawn a new agent container directly (`hive-agent-<name>`). Bypasses
     /// the approval queue — use only as an operator on the host. For
@@ -109,12 +115,17 @@ async fn main() -> Result<()> {
             db,
             dashboard_port,
             operator_pronouns,
+            context_window_tokens,
         } => {
+            let cwt: std::collections::HashMap<String, u64> =
+                serde_json::from_str(&context_window_tokens)
+                    .context("--context-window-tokens: invalid JSON")?;
             let coord = Arc::new(Coordinator::open(
                 &db,
                 hyperhive_flake,
                 dashboard_port,
                 operator_pronouns,
+                cwt,
             )?);
             manager_server::start(coord.clone())?;
             // Idempotent pre-flight: rewrite pre-meta-layout applied

hive-c0re/src/meta.rs

@@ -66,13 +66,14 @@ pub async fn sync_agents(
     hyperhive_flake: &str,
     dashboard_port: u16,
     operator_pronouns: &str,
+    context_window_tokens: &std::collections::HashMap<String, u64>,
     agents: &[AgentSpec],
 ) -> Result<()> {
     let _guard = META_LOCK.lock().await;
     let dir = meta_dir();
     std::fs::create_dir_all(&dir).with_context(|| format!("create {}", dir.display()))?;
 
-    let new_flake = render_flake(hyperhive_flake, dashboard_port, operator_pronouns, agents);
+    let new_flake = render_flake(hyperhive_flake, dashboard_port, operator_pronouns, context_window_tokens, agents);
     let flake_path = dir.join("flake.nix");
     let on_disk = std::fs::read_to_string(&flake_path).unwrap_or_default();
     let initial = !dir.join(".git").exists();
@@ -235,6 +236,7 @@ fn render_flake(
     hyperhive_flake: &str,
     dashboard_port: u16,
     operator_pronouns: &str,
+    context_window_tokens: &std::collections::HashMap<String, u64>,
     agents: &[AgentSpec],
 ) -> String {
     use std::fmt::Write as _;
@@ -283,8 +285,19 @@ fn render_flake(
                 HIVE_PORT = toString port;
                 HIVE_LABEL = name;
                 HIVE_DASHBOARD_PORT = toString dashboardPort;
-                HIVE_OPERATOR_PRONOUNS = operatorPronouns;
+                HIVE_OPERATOR_PRONOUNS = operatorPronouns;"#,
-                HYPERHIVE_STATE_DIR = "/agents/${name}/state";
+    );
+    // Per-model context-window env vars declared in the host-level
+    // `services.hive-c0re.contextWindowTokens` option. Use a sorted
+    // iterator for deterministic flake output (no spurious git diffs).
+    let mut sorted_tokens: Vec<(&String, &u64)> = context_window_tokens.iter().collect();
+    sorted_tokens.sort_by_key(|(k, _)| k.as_str());
+    for (key, val) in &sorted_tokens {
+        let upper_key = key.to_ascii_uppercase();
+        let _ = writeln!(out, "                HIVE_CONTEXT_WINDOW_TOKENS_{upper_key} = \"{val}\";");
+    }
+    out.push_str(
+        r#"                HYPERHIVE_STATE_DIR = "/agents/${name}/state";
               };
             }
           ];

hive-c0re/src/migrate.rs

@@ -83,6 +83,7 @@ pub async fn run(coord: &Arc<Coordinator>) -> Result<()> {
         &coord.hyperhive_flake,
         coord.dashboard_port,
         &coord.operator_pronouns,
+        &coord.context_window_tokens,
         &agents,
     )
     .await

hive-c0re/src/server.rs

@@ -77,6 +77,7 @@ async fn dispatch(req: &HostRequest, coord: Arc<Coordinator>) -> HostResponse {
                     &notes_dir,
                     coord.dashboard_port,
                     &coord.operator_pronouns,
+                    &coord.context_window_tokens,
                 )
                 .await
                 {
@@ -139,6 +140,7 @@ async fn dispatch(req: &HostRequest, coord: Arc<Coordinator>) -> HostResponse {
                     &notes_dir,
                     coord.dashboard_port,
                     &coord.operator_pronouns,
+                    &coord.context_window_tokens,
                 )
                 .await;
                 // Mirror auto_update::rebuild_agent — the manager wants

nix/modules/hive-c0re.nix

@@ -57,6 +57,31 @@ in
         approval needed.
       '';
     };
+    contextWindowTokens = lib.mkOption {
+      type = lib.types.attrsOf lib.types.int;
+      default = {
+        haiku = 200000;
+        sonnet = 1000000;
+        opus = 1000000;
+      };
+      example = {
+        haiku = 150000;
+        sonnet = 900000;
+      };
+      description = ''
+        Per-model context-window sizes in tokens. Each key is a
+        model-family short name matched case-insensitively as a
+        substring of the active model name at runtime (e.g. `"sonnet"`
+        matches `"claude-sonnet-4-5"`). The defaults cover the known
+        Anthropic families; add entries for new models or override
+        existing ones here to change the window for all agents at once.
+
+        Passed to `hive-c0re serve` as JSON and injected into every
+        container's harness service environment as
+        `HIVE_CONTEXT_WINDOW_TOKENS_<KEY_UPPER>`. Changes propagate
+        on the next `↻ R3BU1LD` — no per-agent approval needed.
+      '';
+    };
   };
 
   config = lib.mkIf cfg.enable {
@@ -89,7 +114,7 @@ in
       ];
       environment.HYPERHIVE_GIT = "${pkgs.git}/bin/git";
       serviceConfig = {
-        ExecStart = "${cfg.package}/bin/hive-c0re --socket /run/hyperhive/host.sock serve --hyperhive-flake ${cfg.hyperhiveFlake} --dashboard-port ${toString cfg.dashboardPort} --operator-pronouns ${lib.escapeShellArg cfg.operatorPronouns}";
+        ExecStart = "${cfg.package}/bin/hive-c0re --socket /run/hyperhive/host.sock serve --hyperhive-flake ${cfg.hyperhiveFlake} --dashboard-port ${toString cfg.dashboardPort} --operator-pronouns ${lib.escapeShellArg cfg.operatorPronouns} --context-window-tokens ${lib.escapeShellArg (builtins.toJSON cfg.contextWindowTokens)}";
         Restart = "on-failure";
         RestartSec = 2;
         RuntimeDirectory = "hyperhive";

nix/templates/harness-base.nix

@@ -36,41 +36,6 @@
     '';
   };
 
-  options.hyperhive.contextWindowTokens = lib.mkOption {
-    type = lib.types.attrsOf lib.types.int;
-    # Canonical defaults for known Anthropic model families.
-    # Override any entry in your agent.nix, or add new keys for
-    # model families not listed here.
-    default = {
-      haiku = 200000;
-      sonnet = 1000000;
-      opus = 1000000;
-    };
-    example = {
-      haiku = 150000;
-      sonnet = 900000;
-    };
-    description = ''
-      Per-model context-window sizes in tokens. Each key is a
-      model-family short name (e.g. `"haiku"`, `"sonnet"`) matched as a
-      case-insensitive substring of the active model name at runtime, so
-      `"sonnet"` matches `"claude-sonnet-4-5"` and any future variant.
-
-      The defaults declared here cover the known Anthropic model families.
-      Add or override entries in your `agent.nix` when using a
-      non-standard model or when Anthropic changes a model's window.
-
-      Each entry is rendered as
-      `HIVE_CONTEXT_WINDOW_TOKENS_<KEY_UPPER>` (e.g.
-      `HIVE_CONTEXT_WINDOW_TOKENS_SONNET = "1000000"`). The harness
-      checks these per-model vars in order (first substring match wins),
-      then falls back to `200000` when no key matches. At runtime the
-      effective window drives compaction (75%) and auto-reset (50%)
-      watermarks, and is exposed via `/api/state` as
-      `context_window_tokens`.
-    '';
-  };
-
   options.hyperhive.allowedBashPatterns = lib.mkOption {
     type = lib.types.listOf lib.types.str;
     default = [ ];
@@ -264,25 +229,15 @@
     environment.etc."hyperhive/claude-plugins-auto-update.json".text =
       builtins.toJSON config.hyperhive.claudePluginsAutoUpdate;
 
-    # Model + context-window env vars consumed by the harness at boot.
     # HIVE_DEFAULT_MODEL seeds the initial model selection when no persisted
-    # model choice exists in the state dir.
+    # model choice exists in the state dir. SHELL must be set so claude's
-    # HIVE_CONTEXT_WINDOW_TOKENS_<KEY_UPPER> provides per-model overrides
+    # Bash tool finds a POSIX shell.
-    # (e.g. HIVE_CONTEXT_WINDOW_TOKENS_SONNET) from contextWindowTokens attrset.
+    # HIVE_CONTEXT_WINDOW_TOKENS_* are injected by the meta flake from the
-    # SHELL must be set so claude's Bash tool finds a POSIX shell.
+    # host-level `services.hive-c0re.contextWindowTokens` option — not set here.
-    environment.variables = lib.mkMerge (
+    environment.variables = {
-      [
-        {
       HIVE_DEFAULT_MODEL = config.hyperhive.model;
       SHELL = "${pkgs.bashInteractive}/bin/bash";
-        }
+    };
-      ]
-      ++ lib.mapAttrsToList
-        (model: tokens: {
-          "HIVE_CONTEXT_WINDOW_TOKENS_${lib.toUpper model}" = toString tokens;
-        })
-        config.hyperhive.contextWindowTokens
-    );
 
     boot.isNspawnContainer = true;