busbar-contract: YAML readers behind a yaml feature, enabled by busbar-kernel

.github/workflows/plugin-ci.yml

@@ -378,6 +378,17 @@ jobs:
           printf '%s\n' "$red" | grep -q "crossing(s), pinned" \
             || { printf '%s\n' "$red" >&2; echo "::error::RED: the moved count failed for another reason than the exact comparator"; exit 1; }
           echo "conformance: the published suite ran green; the moved count was refused"
+      - name: "busbar's plane gates over this plane's source (plane-purity, structure-lint, config-schema): no row that passes over busbar's pinned plane fails over this change"
+        # ARCHITECT row 106 (A): a plane that left busbar is read by busbar's gates from its pinned
+        # checkout; here the same gates, at this repo's busbar pin, read THIS change in its place
+        # (BUSBAR_PLANE_SOURCE), so the plane is judged where its source changes.
+        if: ${{ !cancelled() && inputs.plugin_kind == 'plane' && steps.crates.outputs.present == 'true' }}
+        working-directory: busbar
+        env:
+          CRATE: ${{ inputs.plugin_crate }}
+        run: |
+          set -euo pipefail
+          "$PLUGIN_GATES" plugin-gates plane "$GITHUB_WORKSPACE/busbar" "$GITHUB_WORKSPACE/plugin" "${CRATE%-plugin}"
       - name: cargo deny (the rendered deny.toml; busbar's .github/fleet/deps.toml at the pin)
         if: ${{ !cancelled() && steps.crates.outputs.present == 'true' }}
         working-directory: plugin

Cargo.toml

@@ -18,10 +18,8 @@ members = [
     "crates/busbar-kernel-wal",
     "crates/busbar-kernel-audit",
     "crates/busbar-plane-llm",
-    "crates/busbar-plane-mcp",
     "crates/busbar-plane-a2a",
     "crates/busbar-plane-streaming",
-    "crates/busbar-plane-decisions",
     "crates/plugin-loader",
     "crates/busbar-transport-stdio",
     "crates/busbar-transport-webrtc",
@@ -112,6 +110,14 @@ busbar-hook-ranking = { git = "https://github.com/GetBusbar/busbar-hook-ranking"
 # double (`busbar_kernel::test_support::store_double`), and the root's `linked_store_double` tests
 # prove the double states what this door states.
 busbar-store-memory = { git = "https://github.com/GetBusbar/busbar-store-memory", rev = "848851e63ac7a454eb3d5daf9e11d739c48d738b" }
+# THE MCP PLANE (kind: plane), pulled at a pinned rev: the logic crate the root links as the mcp plane's
+# door row (`plane-mcp-door`, `busbar_plane_mcp::tool_door::door`) and installs in every build's tests.
+# Its dropped-in cdylib twin (`busbar-plane-mcp-plugin`) and its gates live in that repo's plugin CI.
+busbar-plane-mcp = { git = "https://github.com/GetBusbar/busbar-plane-mcp", rev = "a5e2ae355c138d8a57a4012225bf441c79bb84bd" }
+# THE DECISIONS PLANE (kind: plane), pulled at a pinned rev: the logic crate the root links as the
+# decisions plane's door row (`plane-decisions`, `busbar_plane_decisions::plane_door::door`). Its
+# dropped-in cdylib twin (`busbar-plane-decisions-plugin`) and its gates live in that repo's plugin CI.
+busbar-plane-decisions = { git = "https://github.com/GetBusbar/busbar-plane-decisions", rev = "d78c070da407c53d7235145fb76d69ed41b7046b" }
 # ── A2A, from the a2aproject's OWN crates ──────────────────────────────────────────────────────
 # THE OBVIOUS NAME IS THE WRONG ONE. `a2a-rs` on crates.io is `emillindfors/a2a-rs` (MIT, v0.5.0) —
 # a different author entirely. The a2aproject family is the `a2a-*-lf` / `a2a-pb` set, all

crates/busbar-contract/Cargo.toml

@@ -105,8 +105,11 @@ crate-type = ["cdylib"]
 [dependencies]
 serde = { workspace = true }
 serde_json = { workspace = true }
-# The section-map split (`section`) reads a plane's section as YAML values, in insertion order.
-serde_yaml = { workspace = true }
+# The section-map split (`section::split_section`) and the door plane's provider list
+# (`plane_calls::dialect_facts`) read a plane's section as YAML values, in insertion order. Optional,
+# behind the `yaml` feature: the host and planes turn it on, so a plugin of another kind (store,
+# secret, auth, hook, export, transport) links no YAML parser and carries no RUSTSEC-2024-0449.
+serde_yaml = { workspace = true, optional = true }
 indexmap = { workspace = true }
 async-trait = { workspace = true }
 futures = { workspace = true }
@@ -150,6 +153,11 @@ hyper = { workspace = true }
 dispatch = []
 runtime = []
 
+# THE YAML READERS (`section::split_section`, `plane_calls::dialect_facts`). OFF by default. On in
+# `busbar-kernel` (the host reads every plane section) and in every plane crate; every other
+# workspace crate that calls them reaches this feature through its `busbar-kernel` edge.
+yaml = ["dep:serde_yaml"]
+
 # The TEST-ONLY seal (#65). `plugin::TestKernelSeal` is the one implementor of the now-SEALED
 # `plugin::KernelSeal` that exists for fixtures rather than for the kernel, and it exists at all
 # because a PLANE crate may not name `caps` (section 1.2) and so cannot mint a real token for its

crates/busbar-contract/src/plane_calls.rs

@@ -172,6 +172,10 @@ pub struct DialectFacts {
 /// the order first referenced, with the `protocol` and `error_map` `lookup` resolves it to (a name
 /// `lookup` does not know is skipped: the configuration's `resolve` refused it). An empty
 /// `error_map` is absent.
+///
+/// Behind the `yaml` feature: the section it reads is a YAML value, and only the host and door
+/// planes build this list.
+#[cfg(feature = "yaml")]
 pub fn dialect_facts(
     section: &serde_yaml::Value,
     lookup: impl Fn(&str) -> Option<(String, std::collections::BTreeMap<String, String>)>,

crates/busbar-contract/src/section.rs

@@ -8,13 +8,16 @@
 //! which are lifted out first as the all-plane `hooks:` attach (a LIST, so ADDITIVE) and the
 //! all-plane `upstream_credentials:` default (a SCALAR, so OVERRIDE).
 //!
-//! [`split_section`] owns the ORDER and every SENTENCE, and a plane supplies the only three things
-//! that differ: the WORDS for its section (the section key and the noun an operator reads back, both
-//! off the plane's own declaration), the TYPE one registration parses into, and its own VALUE RULES.
+//! `split_section` (behind the `yaml` feature) owns the ORDER and every SENTENCE, and a plane
+//! supplies the only three things that differ: the WORDS for its section (the section key and the
+//! noun an operator reads back, both off the plane's own declaration), the TYPE one registration
+//! parses into, and its own VALUE RULES.
 //!
 //! No statics, no I/O and no registry: words and a deserializer in, a split section out. A plane
 //! reads its section through this without naming the kernel or another plane.
 
+// The section split alone reads YAML values; see the `yaml` feature in Cargo.toml.
+#[cfg(feature = "yaml")]
 use serde::Deserialize as _;
 
 /// THE TWO WORDS RESERVED AT EVERY PLANE SECTION'S TOP LEVEL: the all-plane `hooks:` attach list and
@@ -193,6 +196,10 @@ pub struct Section<T> {
 ///
 /// The deserializer's error carrying the refusal sentence: a reserved word used as a registration
 /// name, a malformed reserved knob, a registration that does not parse, or one `validate` refuses.
+///
+/// Behind the `yaml` feature: only the host (`busbar-kernel`) and planes read a section, so a
+/// plugin of another kind does not link a YAML parser.
+#[cfg(feature = "yaml")]
 pub fn split_section<'de, D, T>(
     deserializer: D,
     section: &'static str,

crates/busbar-core-admin/src/tests/planeverbs_tests.rs

@@ -29,7 +29,18 @@ fn shipped_plane_keys() -> Vec<String> {
                 .map(str::to_string)
         })
         .collect();
+    // A PLANE THAT LEFT FOR ITS OWN REPO is still a plane this tree links: the root pins it as a
+    // `git` row of `[workspace.dependencies]` (`busbar-plane-<key> = { git = …, rev = … }`), and
+    // its key is banned exactly as when its crate lived here (ARCHITECT row 106 (A)).
+    let root_manifest = std::fs::read_to_string(crates_dir.join("../Cargo.toml"))
+        .expect("the workspace's root Cargo.toml is readable");
+    keys.extend(root_manifest.lines().filter_map(|l| {
+        let (name, spec) = l.trim().split_once('=')?;
+        let key = name.trim().strip_prefix("busbar-plane-")?;
+        (spec.contains("git =") && !key.ends_with("-plugin")).then(|| key.to_string())
+    }));
     keys.sort();
+    keys.dedup();
     // A derivation that found nothing would make both ratchets below pass on any source at all.
     assert!(
         keys.len() >= 2,

crates/busbar-kernel/Cargo.toml

@@ -36,7 +36,9 @@ bumpalo = { workspace = true }
 # stays on the admin surface; only the neutral scope model lives here, so a non-admin core
 # consumer (router, the chain-verification module, config, config_validate) never has to name
 # "admin" to check a scope.
-busbar-contract = { path = "../busbar-contract" }
+# `yaml`: the host reads every plane's section (`plane::config`, `plane::door`) through the contract's
+# YAML readers; this edge is the one that turns them on for the workspace.
+busbar-contract = { path = "../busbar-contract", features = ["yaml"] }
 # (The HOT-lane plugin/plane ABI the kernel hosts — the `#[repr(C)] PlaneHostVtable` and its POD types
 # — is `busbar_contract::abi::hot` since the #84 merge; consumed HOST-side by `src/plane_host`.)
 # THE ONE NETWORK JUDGE (#36: "the upstream leg — walk + swrr weighting + pre-dial guard; trust

crates/busbar-kernel/src/config_validate/secret_refs.rs

@@ -400,18 +400,11 @@ pub(crate) const SECRET_BEARING_TYPES: &[(&str, SecretBearing)] = &[
     ("AuthChainEntry", SecretBearing::Walked),
     ("IdentityProviderCfg", SecretBearing::Walked),
     ("BrowserLoginCfg", SecretBearing::Walked),
-    // `tools.<name>.token_exchange.subject_token` — busbar's OWN token, the SUBJECT of an RFC 8693
-    // exchange, never the caller's.
-    (
-        "TokenExchangeCfg",
-        SecretBearing::DoorDeclared(
-            "the `tools:` door's section: its Statement declares \
-             `settings.*.token_exchange.subject_token` (and `settings.*.env.*` for a stdio child's \
-             referenced environment), and the folded row's section enumerates every reference at \
-             those paths",
-        ),
-    ),
-    // That plane's LEASED outbound delegation credential. Reached from `RootCfg` through
+    // The `tools:` door's own credential type (`tools.<name>.token_exchange.subject_token`) left
+    // this tree with its plane (the pinned plugin repo, #39): its references are read at the door's
+    // declared `settings.*.token_exchange.subject_token` / `settings.*.env.*` paths through the
+    // `DoorSection` row below, so no type of it is listed here.
+    // The `agents:` plane's LEASED outbound delegation credential. Reached from `RootCfg` through
     // `agent_defs -> agents.<name>.upstream_credential`.
     ("OutboundCredential", SecretBearing::Walked),
     // That plane's OUTBOUND CLIENT CERTIFICATE — busbar's own end of a mutual handshake with a

crates/busbar-kernel/src/trust/tests/genericity_tests.rs

@@ -241,6 +241,17 @@ fn the_lifecycle_names_no_plane_in_its_code() {
             rest.split('-').next().map(str::to_string)
         })
         .collect();
+    // A PLANE THAT LEFT FOR ITS OWN REPO is still a plane this tree links: the root pins it as a
+    // `git` row of `[workspace.dependencies]` (`busbar-plane-<key> = { git = …, rev = … }`), and
+    // its key is banned exactly as when its crate lived here (ARCHITECT row 106 (A)).
+    let root_manifest = std::fs::read_to_string(crates_dir.join("../Cargo.toml"))
+        .expect("the workspace's root Cargo.toml is readable");
+    plane_keys.extend(root_manifest.lines().filter_map(|l| {
+        let (name, spec) = l.trim().split_once('=')?;
+        let rest = name.trim().strip_prefix("busbar-plane-")?;
+        (spec.contains("git =") && !rest.ends_with("-plugin"))
+            .then(|| rest.split('-').next().map(str::to_string))?
+    }));
     plane_keys.sort();
     plane_keys.dedup();
     assert!(