flake: lift cargo test out of buildPackage so prompt edits don't bust the binary cache (#555)

Per mara's review on PR #561: the previous commit kept
`./hive-ag3nt/prompts` in `cleanSrc` because
`hive-ag3nt::prompt::tests` had a compile-time
`include_str!("../prompts/system.md")`. That meant a prompt edit
still busted the cargo cache.

This change:

- Replaces the test-side `include_str!` with a runtime read from
  `$HIVE_ASSETS_DIR/prompts/system.md` (with a CARGO_MANIFEST_DIR
  fallback for plain `cargo test` from a checked-out repo).
- Drops `./hive-ag3nt/prompts` from `cleanSrc` — it's now
  `craneLib.cleanCargoSource ./.` (Cargo.* + *.rs only).
- Sets `doCheck = false` on `packages.default` and lifts
  `cargo test` into a separate `checks.cargo-test` derivation
  that carries the `hyperhive-assets` build input. That scopes the
  asset rebuild blast radius to the test check — `nix flake check`
  still exercises the suite, but the binary derivation no longer
  carries the assets dep.

Verified cache-invariance matrix (via `echo '' >> <f>; nix eval
.#default.outPath`):

| edit                    | default | cargo-test | clippy |
|-------------------------|---------|------------|--------|
| README.md               | stable  | stable     | stable |
| branding/hyperhive.svg  | stable  | CHANGED    | stable |
| nix/modules/*           | stable  | stable     | stable |
| prompts/system.md       | stable  | CHANGED    | stable |
| hive-c0re/src/main.rs   | CHANGED | CHANGED    | CHANGED |

(`cargo-test` CHANGED on prompts/branding is correct — tests
read the production template + need the assets output.)

flake.nix

@@ -46,16 +46,32 @@
             pkgs = nixpkgs.legacyPackages.${system};
             treefmt-eval = treefmt-nix.lib.evalModule pkgs treefmt-config;
             craneLib = crane.mkLib pkgs;
+            # Narrowed source tree the rust derivations consume.
+            # `cleanCargoSource` is crane's standard "everything cargo
+            # cares about" filter (Cargo.toml/Cargo.lock + *.rs). All
+            # non-rust runtime assets — branding + the claude system
+            # prompt template + claude-settings.json — live in the
+            # separate `hyperhive-assets` derivation (#555) and are
+            # loaded by the binaries at runtime from `$HIVE_ASSETS_DIR`.
+            # The unit tests in `hive-ag3nt::prompt` read the same
+            # `prompts/system.md` directly from the workspace tree at
+            # *test* runtime (via `env!("CARGO_MANIFEST_DIR")` — a
+            # compile-time string, no file open at compile), so the
+            # prompt template doesn't have to be in this fileset to
+            # keep `cargo test` honest. Net effect: tweaks to any
+            # non-`*.rs` / non-`Cargo.*` file (README, branding,
+            # nix modules, frontend tree, OR `hive-ag3nt/prompts/*`)
+            # do NOT bust this src hash, so the rust derivations
+            # stay fully cached.
+            cleanSrc = craneLib.cleanCargoSource ./.;
             # Build the workspace's dependency tree once, cached as
             # its own derivation. `buildPackage` and `cargoClippy`
             # both reuse this via `inherit cargoArtifacts;` so a
-            # workspace-only edit doesn't rebuild deps. Same
-            # `nativeBuildInputs` as the workspace build itself —
-            # build.rs runs during dep-build too (any deps with a
-            # build.rs need rsvg too if they transitively pull it
-            # in; harmless if they don't).
+            # workspace-only edit doesn't rebuild deps. All three
+            # derivations consume the same `cleanSrc` so the input
+            # hash stays consistent across the chain.
             cargoArtifacts = craneLib.buildDepsOnly {
-              src = ./.;
+              src = cleanSrc;
               # Workspace Cargo.toml is virtual (no `[package].name`),
               # so crane can't auto-derive a name. Spell it out
               # explicitly here and below — keeps the derivation name
@@ -68,16 +84,16 @@
             };
             # Shared between buildDepsOnly + buildPackage + cargoClippy
             # so the three derivations see the same toolchain shape.
-            # librsvg: hive-c0re/build.rs invokes `rsvg-convert` to
-            # render branding/agent-configs.svg → PNG that the daemon
-            # `include_bytes!`s (#424); SVG stays source-of-truth.
             # git: naersk used to auto-include it; crane is more
             # minimal, so we add it explicitly so hive-c0re's
             # `lifecycle::tests::setup_proposed_*` (which shell out to
             # `git init` + commit) pass under `cargo test` in the
             # sandbox.
+            # `librsvg` used to live here for `hive-c0re/build.rs`'s
+            # rsvg-convert call — that whole codepath moved into the
+            # `hyperhive-assets` derivation in #555, so the rust
+            # derivation no longer needs the dependency.
             nativeBuildInputs = [
-              pkgs.librsvg
               pkgs.git
             ];
           }
@@ -88,17 +104,30 @@
         {
           pkgs,
           craneLib,
+          cleanSrc,
           cargoArtifacts,
           nativeBuildInputs,
           ...
         }:
         {
+          # Build the workspace binaries without running tests. Tests
+          # are run as a separate check (`checks.cargo-test`) that
+          # carries the `hyperhive-assets` build input — `hive-ag3nt::
+          # prompt::tests` reads the production prompt template at test
+          # runtime through `$HIVE_ASSETS_DIR`, so wiring the env var
+          # into the build phase here would make the prompt's hash a
+          # build input of `default` (defeats #555's cache goal: a
+          # prompt edit would still bust the binary derivation, even
+          # though no .rs file changed). Keeping tests in a separate
+          # check derivation localises the asset-rebuild blast radius
+          # to that one check — `nix flake check` still exercises them.
           default = craneLib.buildPackage {
-            src = ./.;
+            src = cleanSrc;
             inherit cargoArtifacts nativeBuildInputs;
             pname = "hyperhive-workspace";
             version = "0.1.0";
             meta.description = "hyperhive workspace (hive-c0re, hive-ag3nt, hive-m1nd)";
+            doCheck = false;
           };
           # Bundled browser assets — see ./nix/frontend.nix. Output is
           # $out/{dashboard,agent}/ which the Rust binaries serve via
@@ -106,6 +135,14 @@
           frontend = pkgs.callPackage ./nix/frontend.nix {
             branding-svg = ./branding/hyperhive.svg;
           };
+          # Static runtime assets the rust binaries read via
+          # `hive_sh4re::assets::*` (#555): branding/* + prompts/*,
+          # plus the rendered agent-configs.png. Split out of the
+          # rust derivation so a tweak to e.g. system.md doesn't bust
+          # the cargo cache. Build input of the `cargo-test` check but
+          # NOT of `packages.default`, so the binary derivation stays
+          # cached when a prompt edit ripples through.
+          assets = pkgs.callPackage ./nix/assets.nix { };
           # Pre-built per-container system closures. Exposed as packages
           # so operators can `nix build .#agent-base-toplevel` (or wire
           # them into their host system closure via the
@@ -137,6 +174,10 @@
           # is applied (manager + agent containers both apply it via
           # `mkContainer` further down).
           hyperhive-frontend = self.packages.${prev.stdenv.hostPlatform.system}.frontend;
+          # Static runtime assets (#555). Exposed alongside the binary
+          # so the harness module can wire $HIVE_ASSETS_DIR straight
+          # to `${pkgs.hyperhive-assets}/share/hyperhive`.
+          hyperhive-assets = self.packages.${prev.stdenv.hostPlatform.system}.assets;
         };
         claude-unstable =
           final: prev:
@@ -171,6 +212,7 @@
         hive-c0re = import ./nix/modules/hive-c0re.nix {
           hyperhivePackage = system: self.packages.${system}.default;
           hyperhiveFrontend = system: self.packages.${system}.frontend;
+          hyperhiveAssets = system: self.packages.${system}.assets;
           hyperhiveFlake = "${self}";
           # Per-container toplevels — wired into `system.extraDependencies`
           # when `services.hive-c0re.preBuildAgentTemplates` is on so the
@@ -237,8 +279,11 @@
 
       checks = forAllSystems (
         {
+          pkgs,
+          system,
           treefmt-eval,
           craneLib,
+          cleanSrc,
           cargoArtifacts,
           nativeBuildInputs,
           ...
@@ -254,12 +299,29 @@
           # separator, which is why the old wiring went through
           # overrideAttrs).
           clippy = craneLib.cargoClippy {
-            src = ./.;
+            src = cleanSrc;
             inherit cargoArtifacts nativeBuildInputs;
             pname = "hyperhive-workspace";
             version = "0.1.0";
             cargoClippyExtraArgs = "--workspace --all-targets -- -D warnings";
           };
+          # `cargo test --workspace` lifted out of `buildPackage` so the
+          # `hyperhive-assets` dep (which `hive-ag3nt::prompt::tests`
+          # needs via `HIVE_ASSETS_DIR` to assert against the actual
+          # production prompt template) is scoped to this one check
+          # instead of bleeding into the binary derivation's input
+          # hash. Net: editing `hive-ag3nt/prompts/system.md` still
+          # rebuilds this test check (correct — the tests assert
+          # against its wording), but `packages.default` and the
+          # per-container toplevels stay fully cached.
+          cargo-test = craneLib.cargoTest {
+            src = cleanSrc;
+            inherit cargoArtifacts nativeBuildInputs;
+            pname = "hyperhive-workspace";
+            version = "0.1.0";
+            cargoTestExtraArgs = "--workspace";
+            HIVE_ASSETS_DIR = "${self.packages.${system}.assets}/share/hyperhive";
+          };
         }
       );
     };

hive-ag3nt/src/prompt.rs

@@ -29,22 +29,24 @@
 
 use std::path::{Path, PathBuf};
 
-use anyhow::Result;
+use anyhow::{Context, Result};
 
 use crate::mcp::Flavor;
 
-const TEMPLATE: &str = include_str!("../prompts/system.md");
-
 /// Assemble the system prompt for a given flavor + label + pronouns.
 /// Pure function — no I/O. Splits out from [`write_system_prompt`] so
 /// the marker logic + substitution is unit-testable in isolation.
+/// The caller supplies the template body so tests can pass an inline
+/// fixture and production reads it once at harness startup via
+/// [`hive_sh4re::assets::prompt_template`] (`$HIVE_ASSETS_DIR/prompts/
+/// system.md`).
 #[must_use]
-pub fn render(flavor: Flavor, label: &str, operator_pronouns: &str) -> String {
+pub fn render(template: &str, flavor: Flavor, label: &str, operator_pronouns: &str) -> String {
     let target = match flavor {
         Flavor::Agent => "agent",
         Flavor::Manager => "manager",
     };
-    let body = filter_role_blocks(TEMPLATE, target);
+    let body = filter_role_blocks(template, target);
     body.replace("{label}", label)
         .replace("{operator_pronouns}", operator_pronouns)
 }
@@ -115,15 +117,20 @@ fn parse_close_marker(line: &str) -> Option<&str> {
 /// # Errors
 ///
 /// Returns an error if the system prompt file cannot be written.
-pub async fn write_system_prompt(
-    socket: &Path,
-    label: &str,
-    flavor: Flavor,
-) -> Result<PathBuf> {
+pub async fn write_system_prompt(socket: &Path, label: &str, flavor: Flavor) -> Result<PathBuf> {
     let parent = socket.parent().unwrap_or_else(|| Path::new("/run/hive"));
     tokio::fs::create_dir_all(parent).await.ok();
     let pronouns = std::env::var("HIVE_OPERATOR_PRONOUNS").unwrap_or_else(|_| "she/her".to_owned());
-    let body = render(flavor, label, &pronouns);
+    let template_path = hive_sh4re::assets::prompt_template();
+    let template = tokio::fs::read_to_string(&template_path)
+        .await
+        .with_context(|| {
+            format!(
+                "read claude system prompt template from {}",
+                template_path.display()
+            )
+        })?;
+    let body = render(&template, flavor, label, &pronouns);
     let path = parent.join("claude-system-prompt.md");
     tokio::fs::write(&path, body).await?;
     tracing::info!(path = %path.display(), "wrote claude system prompt");
@@ -133,6 +140,36 @@ pub async fn write_system_prompt(
 #[cfg(test)]
 mod tests {
     use super::*;
+    use std::sync::LazyLock;
+
+    // #555: the production template lives at
+    // `$HIVE_ASSETS_DIR/prompts/system.md` and is loaded at runtime.
+    // The unit tests below want to assert against the actual production
+    // wording (so the renderer + tool surface stay honest), so they
+    // resolve the same path at test runtime via two fallbacks:
+    //   1. `$HIVE_ASSETS_DIR/prompts/system.md` — the runtime contract
+    //      production uses. The flake's `checks.cargo-test` derivation
+    //      sets this to the `hyperhive-assets` output so `cargo test`
+    //      inside the nix sandbox finds the file without needing
+    //      `prompts/` in the cargo source tree. `packages.default`
+    //      explicitly does NOT carry the assets dep, so a prompt edit
+    //      doesn't bust the binary derivation — only this test check.
+    //   2. `env!("CARGO_MANIFEST_DIR")/prompts/system.md` — for plain
+    //      `cargo test --workspace` from a checked-out repo where the
+    //      env var isn't set; `env!` is a compile-time string lookup,
+    //      no file open at compile, so this still doesn't pull
+    //      `prompts/` into the build hash.
+    // The combined effect is that the flake's `cleanSrc` no longer
+    // unions `./hive-ag3nt/prompts` — tweaks to system.md don't bust
+    // the cargo cache anymore.
+    static PRODUCTION_TEMPLATE: LazyLock<String> = LazyLock::new(|| {
+        let path = match std::env::var("HIVE_ASSETS_DIR") {
+            Ok(v) if !v.is_empty() => format!("{v}/prompts/system.md"),
+            _ => concat!(env!("CARGO_MANIFEST_DIR"), "/prompts/system.md").to_owned(),
+        };
+        std::fs::read_to_string(&path)
+            .unwrap_or_else(|e| panic!("read production prompt template at {path}: {e}"))
+    });
 
     const SAMPLE: &str = "\
 shared opener
@@ -233,7 +270,7 @@ shared closer
         // Real template's first agent line — keeps the renderer
         // honest about the {label} / {operator_pronouns} pair the
         // harness already relied on.
-        let rendered = render(Flavor::Agent, "alice", "they/them");
+        let rendered = render(&PRODUCTION_TEMPLATE, Flavor::Agent, "alice", "they/them");
         assert!(rendered.contains("hyperhive agent `alice`"));
         assert!(rendered.contains("**they/them** pronouns"));
         assert!(!rendered.contains("{label}"));
@@ -246,7 +283,7 @@ shared closer
         // kill, schedule_*) MUST NOT appear in the agent's rendered
         // prompt. Drift between flavor and tool surface bites every
         // time it happens (cf. #511 missing-allow-list bug).
-        let rendered = render(Flavor::Agent, "alice", "she/her");
+        let rendered = render(&PRODUCTION_TEMPLATE, Flavor::Agent, "alice", "she/her");
         assert!(!rendered.contains("request_init_config"));
         assert!(!rendered.contains("request_apply_commit"));
         assert!(!rendered.contains("get_logs"));
@@ -257,7 +294,7 @@ shared closer
 
     #[test]
     fn render_manager_includes_manager_only_tools() {
-        let rendered = render(Flavor::Manager, "hm1nd", "she/her");
+        let rendered = render(&PRODUCTION_TEMPLATE, Flavor::Manager, "hm1nd", "she/her");
         assert!(rendered.contains("request_init_config"));
         assert!(rendered.contains("request_apply_commit"));
         assert!(rendered.contains("get_logs"));
@@ -269,9 +306,9 @@ shared closer
 
     #[test]
     fn render_uses_correct_role_opener() {
-        let agent = render(Flavor::Agent, "alice", "she/her");
+        let agent = render(&PRODUCTION_TEMPLATE, Flavor::Agent, "alice", "she/her");
         assert!(agent.starts_with("You are hyperhive agent"));
-        let manager = render(Flavor::Manager, "hm1nd", "she/her");
+        let manager = render(&PRODUCTION_TEMPLATE, Flavor::Manager, "hm1nd", "she/her");
         assert!(manager.starts_with("You are the hyperhive manager"));
     }
 }

hive-ag3nt/src/turn.rs

@@ -10,7 +10,7 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex};
 use std::time::Duration;
 
-use anyhow::{Result, bail};
+use anyhow::{Context, Result, bail};
 use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
 use tokio::process::Command;
 
@@ -18,15 +18,14 @@ use crate::events::{Bus, LiveEvent};
 use crate::login::LoginState;
 use crate::mcp;
 
-/// `--settings` JSON applied to every claude invocation. Lives as a
-/// properly-formatted file in `prompts/claude-settings.json` so it's easy
-/// to read and edit; we ship it via `include_str!`. We turn off claude's
-/// in-session auto-compaction and its cross-session auto-memory because
-/// hyperhive owns those concerns (`/compact` on overflow, notes
-/// persistence under `/state`). Unknown keys are silently ignored by
-/// claude-code; if a key gets renamed we'll spot it because the
-/// corresponding behavior will start firing mid-turn again.
-const CLAUDE_SETTINGS: &str = include_str!("../prompts/claude-settings.json");
+// `--settings` JSON is read at runtime from
+// `$HIVE_ASSETS_DIR/prompts/claude-settings.json` via
+// `hive_sh4re::assets::claude_settings()` (#555). We turn off claude's
+// in-session auto-compaction and its cross-session auto-memory because
+// hyperhive owns those concerns (`/compact` on overflow, notes
+// persistence under `/state`). Unknown keys are silently ignored by
+// claude-code; if a key gets renamed we'll spot it because the
+// corresponding behavior will start firing mid-turn again.
 
 /// Regex-ish marker claude-code emits when context overflows. Same string
 /// bitburner-agent watches for. Empirically reliable across claude-code
@@ -159,7 +158,14 @@ pub async fn write_settings(socket: &Path) -> Result<PathBuf> {
     let parent = socket.parent().unwrap_or_else(|| Path::new("/run/hive"));
     tokio::fs::create_dir_all(parent).await.ok();
     let path = parent.join("claude-settings.json");
-    tokio::fs::write(&path, CLAUDE_SETTINGS).await?;
+    // #555: source-of-truth is `$HIVE_ASSETS_DIR/prompts/claude-settings.json`;
+    // copy through the per-agent runtime dir so claude reads it from the
+    // same socket-adjacent location every time and so a future override
+    // (per-agent settings JSON layer) drops in cleanly.
+    let src = hive_sh4re::assets::claude_settings();
+    tokio::fs::copy(&src, &path)
+        .await
+        .with_context(|| format!("copy claude settings from {} to {}", src.display(), path.display()))?;
     tracing::info!(path = %path.display(), "wrote claude settings");
     Ok(path)
 }
@@ -508,10 +514,10 @@ pub async fn wait_for_login(
 /// regular files + newest `mtime` across them. The two axes are both
 /// load-bearing for `wait_for_login`'s refresh check (`session_refreshed`):
 /// mtime catches the common case (re-login overwrites an existing
-/// credentials file in-place), file_count catches the pathological case
+/// credentials file in-place), `file_count` catches the pathological case
 /// where `meta.modified()` errors on every file (exotic fs, NFS quirks)
 /// so the mtime axis stays `None` forever but new files still trigger a
-/// resume. Defaults to `{0, None}` on read_dir failure (missing or
+/// resume. Defaults to `{0, None}` on `read_dir` failure (missing or
 /// unreadable dir) — `wait_for_login` then resumes when files first
 /// appear.
 #[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
@@ -542,9 +548,9 @@ fn snapshot_dir(dir: &Path) -> DirSnapshot {
 /// Has the credentials dir been written since `prev`? Used as the
 /// exit condition for `wait_for_login`:
 ///
-/// - file_count changed → something was added or removed, treat as
+/// - `file_count` changed → something was added or removed, treat as
 ///   refresh (covers the "all files have unreadable mtime" edge case).
-/// - newest_mtime advanced → existing file was rewritten in place
+/// - `newest_mtime` advanced → existing file was rewritten in place
 ///   (the common claude re-login path).
 /// - prev had no mtime (empty or all-unreadable) and now has one →
 ///   first useful signal we've seen, treat as refresh.

hive-ag3nt/src/web_ui.rs

@@ -221,9 +221,15 @@ fn try_bind(addr: SocketAddr) -> std::io::Result<tokio::net::TcpListener> {
 /// Always returns an image, so consumers (dashboard, favicon) can hit
 /// `/icon` unconditionally without probing whether one is configured.
 async fn serve_icon() -> impl IntoResponse {
-    const DEFAULT_ICON: &str = include_str!("../../branding/hyperhive.svg");
-    let body = std::fs::read_to_string("/etc/hyperhive/icon.svg")
-        .unwrap_or_else(|_| DEFAULT_ICON.to_string());
+    // Per-agent icon overrides go through `/etc/hyperhive/icon.svg` (set
+    // via the `hyperhive.icon` agent.nix option); the bundled default is
+    // resolved at runtime from
+    // `$HIVE_ASSETS_DIR/branding/hyperhive.svg` (#555). If neither file
+    // can be read we serve an empty body — keeps the response a valid
+    // SVG content-type without a panic on a misconfigured container.
+    let body = std::fs::read_to_string("/etc/hyperhive/icon.svg").unwrap_or_else(|_| {
+        std::fs::read_to_string(hive_sh4re::assets::branding_svg()).unwrap_or_default()
+    });
     ([("content-type", "image/svg+xml")], body)
 }
 

hive-c0re/Cargo.toml

@@ -2,13 +2,6 @@
 name = "hive-c0re"
 edition.workspace = true
 version.workspace = true
-# Render branding/agent-configs.svg → $OUT_DIR/agent-configs.png at
-# compile time (#424). build.rs shells out to `rsvg-convert`
-# (librsvg, pulled in via flake.nix' crane nativeBuildInputs); the
-# baked PNG is included via include_bytes! from forge.rs so no
-# raster gets checked into git.
-build = "build.rs"
-
 [lints]
 workspace = true
 

hive-c0re/build.rs

@@ -1,49 +0,0 @@
-//! Render `branding/agent-configs.svg` → `$OUT_DIR/agent-configs.png`
-//! at compile time so the daemon can `include_bytes!` the PNG without
-//! checking the raster into git (#424 mara: "generate png on the fly
-//! or in build"). The SVG is the source of truth; the PNG is a build
-//! artifact.
-//!
-//! Uses `rsvg-convert` from PATH (librsvg, already available in
-//! nixpkgs and added to the crane derivation's `nativeBuildInputs`
-//! in `flake.nix`). For dev builds outside Nix, install librsvg via
-//! your system package manager (Debian/Ubuntu: `librsvg2-bin`,
-//! macOS: `brew install librsvg`).
-
-use std::env;
-use std::path::PathBuf;
-use std::process::Command;
-
-const SVG_PATH: &str = "../branding/agent-configs.svg";
-const PNG_NAME: &str = "agent-configs.png";
-// 300×300 to match the existing branding/hyperhive.png, which the
-// Forgejo avatar endpoint accepts without resizing on upload.
-const PX: &str = "300";
-
-fn main() {
-    // Re-run the build script when either the SVG itself or this
-    // script change. We deliberately don't watch every file in
-    // `branding/` — only the one PNG we generate.
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-changed={SVG_PATH}");
-
-    let out_dir = PathBuf::from(env::var("OUT_DIR").expect("OUT_DIR set by cargo"));
-    let png_path = out_dir.join(PNG_NAME);
-
-    let status = Command::new("rsvg-convert")
-        .args(["--width", PX, "--height", PX, "-o"])
-        .arg(&png_path)
-        .arg(SVG_PATH)
-        .status();
-
-    match status {
-        Ok(s) if s.success() => {}
-        Ok(s) => panic!("rsvg-convert exited with {s} rendering {SVG_PATH}"),
-        Err(e) => panic!(
-            "failed to invoke rsvg-convert: {e}\n\
-             install librsvg (Debian/Ubuntu: librsvg2-bin, macOS: brew install librsvg, \
-             NixOS: pkgs.librsvg). The Nix derivation already pulls it in via \
-             flake.nix → craneLib.buildPackage.nativeBuildInputs.",
-        ),
-    }
-}

hive-c0re/src/forge.rs

@@ -41,20 +41,14 @@ const CORE_AVATAR_MARKER: &str = "/var/lib/hyperhive/forge-core-avatar-set";
 /// Sibling marker for the `agent-configs` org avatar (#424). Same one-
 /// shot semantics — delete to force the upload to re-run.
 const CONFIG_ORG_AVATAR_MARKER: &str = "/var/lib/hyperhive/forge-agent-configs-avatar-set";
-/// Hyperhive logo bytes, baked into the daemon. Uploaded once via the
-/// admin avatar API so the `core` Forgejo user shows the project mark
-/// next to commits in `agent-configs/*`, `core/meta`, etc. instead of
-/// the default hash identicon.
-const CORE_AVATAR_PNG: &[u8] = include_bytes!("../../branding/hyperhive.png");
-/// `agent-configs` org logo bytes (#424). Sibling visual to the main
-/// hyperhive mark — same dark base + outer ring + corner brackets,
-/// with a stacked-config-files glyph in the centre so the operator
-/// can distinguish the agent-configs namespace from the main
-/// `hyperhive` org at a glance. Source-of-truth is
-/// `branding/agent-configs.svg`; `hive-c0re/build.rs` renders it
-/// into `$OUT_DIR/agent-configs.png` at compile time via
-/// `rsvg-convert` so the raster never gets checked into git.
-const CONFIG_ORG_AVATAR_PNG: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/agent-configs.png"));
+// Avatar PNGs are loaded at runtime from
+// `$HIVE_ASSETS_DIR/branding/{hyperhive,agent-configs}.png` via the
+// helpers in `hive_sh4re::assets` (#555 — was `include_bytes!` of an
+// in-source path and an OUT_DIR-rendered sibling, both of which
+// invalidated the crane src cache on any branding edit). The
+// `agent-configs.png` is rendered from its SVG during the
+// `hyperhive-assets` derivation's build (was `hive-c0re/build.rs`
+// + `rsvg-convert` on PATH; both gone now).
 /// Forgejo org grouping every agent's applied config repo. Core is a
 /// site admin and reads + writes every repo here; agents are NOT
 /// members and the repos are private, so no agent — not even the one
@@ -298,9 +292,13 @@ async fn ensure_core_avatar(token: &str) -> Result<()> {
     if marker.exists() {
         return Ok(());
     }
+    let png_path = hive_sh4re::assets::core_avatar_png();
+    let png_bytes = tokio::fs::read(&png_path)
+        .await
+        .with_context(|| format!("read core avatar PNG from {}", png_path.display()))?;
     let body = format!(
         r#"{{"image":"{}"}}"#,
-        base64::engine::general_purpose::STANDARD.encode(CORE_AVATAR_PNG),
+        base64::engine::general_purpose::STANDARD.encode(&png_bytes),
     );
     let url = format!("{FORGE_HTTP}/api/v1/admin/users/core/avatar");
     let status = forge_http(reqwest::Method::POST, &url, token, &body).await?;
@@ -325,9 +323,13 @@ async fn ensure_config_org_avatar(token: &str) -> Result<()> {
     if marker.exists() {
         return Ok(());
     }
+    let png_path = hive_sh4re::assets::config_org_avatar_png();
+    let png_bytes = tokio::fs::read(&png_path)
+        .await
+        .with_context(|| format!("read {CONFIG_ORG} avatar PNG from {}", png_path.display()))?;
     let body = format!(
         r#"{{"image":"{}"}}"#,
-        base64::engine::general_purpose::STANDARD.encode(CONFIG_ORG_AVATAR_PNG),
+        base64::engine::general_purpose::STANDARD.encode(&png_bytes),
     );
     let url = format!("{FORGE_HTTP}/api/v1/orgs/{CONFIG_ORG}/avatar");
     let status = forge_http(reqwest::Method::POST, &url, token, &body).await?;

hive-sh4re/src/assets.rs

@@ -0,0 +1,99 @@
+//! Resolve the on-disk path to hyperhive's static assets (branding +
+//! claude prompts). Single source of truth for both the host daemon
+//! (`hive-c0re`) and the in-container harness (`hive-ag3nt` /
+//! `hive-m1nd`) so they agree on the lookup contract.
+//!
+//! At runtime, the path is read from `$HIVE_ASSETS_DIR`. In nix
+//! builds that env var is set by the `hive-c0re` / `harness-base` modules
+//! to `${pkgs.hyperhive-assets}/share/hyperhive` (see `nix/assets.nix`).
+//! For `cargo run` outside nix, set it yourself:
+//!
+//! ```sh
+//! HIVE_ASSETS_DIR=$(pwd)/dev-assets cargo run ...
+//! ```
+//!
+//! where `dev-assets/` is laid out the same as the nix output:
+//!
+//! ```text
+//! dev-assets/
+//!   branding/
+//!     hyperhive.{svg,png}
+//!     agent-configs.{svg,png}
+//!   prompts/
+//!     system.md
+//!     claude-settings.json
+//! ```
+//!
+//! A convenience `cargo xtask seed-dev-assets` could materialise this
+//! by copying `branding/` + `hive-ag3nt/prompts/` + rendering
+//! `agent-configs.png` via rsvg-convert, but it's intentionally not
+//! shipped yet — dev setups vary too much for one helper to fit.
+//!
+//! Each crate that wants a specific asset goes through one of the
+//! typed helpers (`branding_svg()`, `prompt_template()`, …) so the
+//! lookup contract is centralised. Missing files panic at first
+//! call with a clear "set `HIVE_ASSETS_DIR` + put the file at …"
+//! message — same failure shape as the old `include_*!` macros
+//! (which would have failed at compile time, not runtime, but the
+//! diagnostic value is identical).
+
+use std::path::PathBuf;
+
+/// Read `$HIVE_ASSETS_DIR`. Panics with a clear remediation message
+/// when unset — every code path that calls into this module is one
+/// the binary cannot run without, so a hard early failure is the
+/// right shape.
+fn dir() -> PathBuf {
+    match std::env::var("HIVE_ASSETS_DIR") {
+        Ok(v) if !v.is_empty() => PathBuf::from(v),
+        _ => panic!(
+            "HIVE_ASSETS_DIR is not set. Inside the nix-built systemd \
+             units this is wired automatically from \
+             `pkgs.hyperhive-assets`; for `cargo run` outside nix, \
+             set it to a directory laid out like \
+             `nix/assets.nix`'s output (branding/ + prompts/ \
+             subdirs). See hive-sh4re/src/assets.rs for the contract.",
+        ),
+    }
+}
+
+/// `$HIVE_ASSETS_DIR/branding/hyperhive.svg` — the project's primary
+/// mark. Loaded by the per-agent web UI as its default icon
+/// (`/agents/<n>/icon.svg` falls through here when the agent didn't
+/// override `hyperhive.icon` in its `agent.nix`).
+#[must_use]
+pub fn branding_svg() -> PathBuf {
+    dir().join("branding/hyperhive.svg")
+}
+
+/// `$HIVE_ASSETS_DIR/branding/hyperhive.png` — the same mark
+/// rasterised, used by `hive-c0re::forge::push_avatar` to upload
+/// the forge org avatar.
+#[must_use]
+pub fn core_avatar_png() -> PathBuf {
+    dir().join("branding/hyperhive.png")
+}
+
+/// `$HIVE_ASSETS_DIR/branding/agent-configs.png` — secondary org
+/// mark for the `agent-configs/` mirror org. Rendered from
+/// `agent-configs.svg` at asset-build time (was rendered in
+/// `hive-c0re/build.rs` before #555).
+#[must_use]
+pub fn config_org_avatar_png() -> PathBuf {
+    dir().join("branding/agent-configs.png")
+}
+
+/// `$HIVE_ASSETS_DIR/prompts/system.md` — the claude system prompt
+/// template. `hive-ag3nt::prompt::render` filters the role markers
+/// inside it per agent / manager flavor.
+#[must_use]
+pub fn prompt_template() -> PathBuf {
+    dir().join("prompts/system.md")
+}
+
+/// `$HIVE_ASSETS_DIR/prompts/claude-settings.json` — the static
+/// `--settings` JSON every claude invocation reads.
+#[must_use]
+pub fn claude_settings() -> PathBuf {
+    dir().join("prompts/claude-settings.json")
+}

hive-sh4re/src/lib.rs

@@ -2,6 +2,8 @@
 
 use serde::{Deserialize, Serialize};
 
+pub mod assets;
+
 // -----------------------------------------------------------------------------
 // Host admin socket — /run/hyperhive/host.sock
 // -----------------------------------------------------------------------------

nix/assets.nix

@@ -0,0 +1,77 @@
+{
+  stdenv,
+  lib,
+  librsvg,
+}:
+
+# Static assets the rust workspace reads at runtime: the project's
+# branding SVG/PNG family + the claude system-prompt template +
+# claude-settings JSON. Lives as its own derivation so a tweak to
+# branding/agent-configs.svg or hive-ag3nt/prompts/system.md doesn't
+# invalidate the rust derivation's cargo cache (closes #555 follow-up
+# to #538 — naersk previously paired with `src = ./.;` invalidating
+# every rust build on any branding/prompt edit; crane inherited that
+# coupling and this split breaks it cleanly).
+#
+# Output layout:
+#
+#   $out/share/hyperhive/branding/{hyperhive.svg, hyperhive.png,
+#                                  agent-configs.svg, agent-configs.png}
+#   $out/share/hyperhive/prompts/{system.md, claude-settings.json}
+#
+# The agent-configs PNG is rendered at build time from the SVG via
+# rsvg-convert — same shape as the old `hive-c0re/build.rs` rasteriser,
+# just hoisted into nix so the librsvg dependency stays *here* instead
+# of in the rust derivation's nativeBuildInputs.
+
+stdenv.mkDerivation {
+  pname = "hyperhive-assets";
+  version = "0.1.0";
+  # `src` is intentionally narrow — only branding/ + the hive-ag3nt/prompts/
+  # subdir, NOT the whole tree. Keeps the input hash decoupled from
+  # rust source / docs / nix module edits.
+  srcs = [
+    ../branding
+    ../hive-ag3nt/prompts
+  ];
+  # `unpackPhase` would normally extract each src to its own dir; we
+  # just want them side-by-side, so hand-roll a flat copy.
+  unpackPhase = ''
+    runHook preUnpack
+    cp -r ${../branding} branding
+    cp -r ${../hive-ag3nt/prompts} prompts
+    chmod -R u+w branding prompts
+    runHook postUnpack
+  '';
+
+  nativeBuildInputs = [ librsvg ];
+
+  # No real build step — just render the agent-configs PNG alongside
+  # its SVG. 300×300 matches branding/hyperhive.png, which is the size
+  # Forgejo's avatar endpoint accepts without resampling on upload (the
+  # same constraint hive-c0re/build.rs encoded).
+  buildPhase = ''
+    runHook preBuild
+    rsvg-convert --width 300 --height 300 \
+      -o branding/agent-configs.png \
+      branding/agent-configs.svg
+    runHook postBuild
+  '';
+
+  installPhase = ''
+    runHook preInstall
+    mkdir -p $out/share/hyperhive
+    cp -r branding $out/share/hyperhive/branding
+    cp -r prompts $out/share/hyperhive/prompts
+    runHook postInstall
+  '';
+
+  # Pure data — no executables to fixup, no shared libs to patchelf.
+  dontFixup = true;
+
+  meta = {
+    description = "hyperhive static assets (branding + claude prompts)";
+    homepage = "https://forge.darkest.space/hyperhive/hyperhive";
+    license = lib.licenses.mit;
+  };
+}

nix/modules/hive-c0re.nix

@@ -1,6 +1,7 @@
 {
   hyperhivePackage,
   hyperhiveFrontend,
+  hyperhiveAssets,
   hyperhiveFlake,
   agentBaseToplevel,
   managerToplevel,
@@ -66,6 +67,20 @@ in
         endpoints) is the source of truth for any replacement.
       '';
     };
+    assets = lib.mkOption {
+      type = lib.types.package;
+      default = hyperhiveAssets pkgs.stdenv.hostPlatform.system;
+      defaultText = lib.literalExpression "hyperhive.packages.\${system}.assets";
+      description = ''
+        Bundled static runtime assets (see `./nix/assets.nix`): the
+        project's branding family + the claude system-prompt template +
+        claude-settings JSON. Output has `share/hyperhive/{branding,prompts}/`;
+        passed to hive-c0re's systemd unit via `HIVE_ASSETS_DIR`
+        (`hive_sh4re::assets::*` resolve paths underneath). Override to
+        ship customised branding or prompts without rebuilding the
+        rust derivation.
+      '';
+    };
     hyperhiveFlake = lib.mkOption {
       type = lib.types.str;
       default = hyperhiveFlake;
@@ -196,6 +211,10 @@ in
         # serves this via `tower_http::ServeDir` for any path it doesn't
         # match against an API/action route.
         HIVE_STATIC_DIR = "${cfg.frontend}/dashboard";
+        # Path to the static runtime asset tree (branding + claude
+        # prompts). `hive_sh4re::assets::*` reads paths underneath.
+        # `forge.rs` reads the avatar PNGs from here on startup.
+        HIVE_ASSETS_DIR = "${cfg.assets}/share/hyperhive";
       }
       // lib.optionalAttrs config.hyperhive.forge.enable {
         # Agents poll this URL for Forgejo notifications. Derived from

nix/templates/harness-base.nix

@@ -531,10 +531,15 @@
     # HIVE_DEFAULT_MODEL seeds the initial model selection when no persisted
     # model choice exists in the state dir. SHELL must be set so claude's
     # Bash tool finds a POSIX shell.
+    # HIVE_ASSETS_DIR points at the project's static runtime assets
+    # (branding + claude prompts; see `nix/assets.nix`). Set here so
+    # both the harness binary and any user-shell `cargo run` inside the
+    # container resolve them from the same path.
     # HIVE_CONTEXT_WINDOW_TOKENS_* are injected by the meta flake from the
     # host-level `services.hive-c0re.contextWindowTokens` option — not set here.
     environment.variables = {
       HIVE_DEFAULT_MODEL = config.hyperhive.model;
+      HIVE_ASSETS_DIR = "${pkgs.hyperhive-assets}/share/hyperhive";
       SHELL = "${pkgs.bashInteractive}/bin/bash";
     } // lib.optionalAttrs (!config.hyperhive.autoCompact) {
       # Zero watermark disables proactive compaction; the reactive path