feat(config): add manifest adapter for non-Gleam workspaces

.changes/unreleased/Added-20260819-adapter-doctor-checks.yaml

@@ -0,0 +1,7 @@
+component: doctor
+kind: Added
+body: |-
+  **`doctor` checks an adapter workspace's own invariants instead of Gleam's.** Every member manifest must declare a version that parses as semver (an error), and a name matching its directory (a warning — nothing downstream requires them to agree, and repositories in the wild do drift here).
+
+    The checks with nothing to read are dropped: `manifest.toml` lock drift, shared external dependency agreement, and the `gleam`-on-PATH toolchain pin. The `checked:` preamble now names the checks that actually ran rather than a fixed list.
+time: 2026-08-19T09:02:00.000000-07:00

.changes/unreleased/Added-20260819-adapter-manifest-seam.yaml

@@ -0,0 +1,9 @@
+component: trellis
+kind: Added
+body: |-
+  **`[tools.trellis.adapter]` lets a workspace's members be something other than Gleam packages.** One key is required — `manifest`, the member manifest's path relative to the member directory, whose presence marks a member the way a `gleam.toml` does otherwise, and whose extension picks the format (`.toml`, `.json`, `.yaml`, `.yml`). `name` and `version` are dotted field paths into that manifest, defaulting to `name` and `version`. Built for repositories distributed by git ref rather than a registry: Claude Code plugin marketplaces, APM monorepos, AI skill collections.
+
+    Trellis also accepts a **`trellis.toml`** at the workspace root carrying the same `[tools.trellis]` table, since an adapter workspace usually has no `gleam.toml` for it to live in. Root discovery walks up to the first directory whose `trellis.toml` or `gleam.toml` carries the table, preferring `trellis.toml`; carrying it in both at once is an error.
+
+    The dependency graph is flat under an adapter — no dependency edges are declared, so topological order is member order and a workspace dependency never ripple-bumps. `publish.lifecycle` defaults to `git_only` and `hex` anywhere under an adapter is a configuration error, because there is no registry to publish to.
+time: 2026-08-19T09:00:00.000000-07:00

.changes/unreleased/Added-20260819-adapter-version-writeback.yaml

@@ -0,0 +1,7 @@
+component: version
+kind: Added
+body: |-
+  **`version apply` writes the bump into the field `[tools.trellis.adapter].version` names.** The edit is surgical for JSON and YAML as it already was for TOML: only that scalar changes, so a hand-maintained `plugin.json` or `apm.yml` keeps its comments, key order, indentation, and quote style byte for byte. A field path that resolves to nothing, or to a mapping, sequence, or non-string, is an error — the bump never inserts a key.
+
+    The `manifest.toml` lockfile patch is skipped in an adapter workspace, which has no Gleam lock to keep in step.
+time: 2026-08-19T09:01:00.000000-07:00

.changes/unreleased/Changed-20260819-adapter-refusals.yaml

@@ -0,0 +1,7 @@
+component: run
+kind: Changed
+body: |-
+  **The built-in verbs are refused in an adapter workspace, and name the tasks you have declared.** `build`, `test`, `check`, `docs`, `deps`, `format`, and `clean` all shell out to `gleam`, which an adapter workspace's members are not. Declare what you need under `[tools.trellis.tasks]` — a custom task with a built-in's name still overrides it, and `trellis exec` is unaffected.
+
+    `publish`, `lockfile refresh`, and `new` are refused for the same reason.
+time: 2026-08-19T09:03:00.000000-07:00

.changes/unreleased/Fixed-20260819-init-sees-trellis-toml.yaml

@@ -0,0 +1,5 @@
+component: init
+kind: Fixed
+body: |-
+  **`init` refuses a repository already configured by a `trellis.toml`.** It only looked for a `[tools.trellis]` table in `gleam.toml` files, so in a workspace configured the new way it wrote a second config home — a state every later command then rejects as ambiguous. Member manifests are checked for both spellings too.
+time: 2026-08-19T09:04:00.000000-07:00

Cargo.toml

@@ -55,6 +55,7 @@ toml = "1.1.2"
 toml_edit = "0.25.12"
 ureq = { version = "3.3.0", features = ["json"] }
 serde_ignored = "0.1.14"
+saphyr-parser = "0.0.12"
 
 [dev-dependencies]
 assert_cmd = "2.2.2"

README.md

@@ -21,6 +21,13 @@ version, and path dependencies. The dependency graph — topological order,
 publish order, change impact, path-dep rewrite maps — is computed, never
 declared.
 
+Gleam is the native, batteries-included ecosystem. For a repository whose
+packages are not Gleam packages — a Claude Code plugin marketplace, an APM
+monorepo, anything distributed by git ref rather than a registry — a
+[`[tools.trellis.adapter]`](#manifest-adapter) table redefines which file marks
+a member and where its name and version live. Everything downstream is the same
+code.
+
 See [docs/DESIGN.md](docs/DESIGN.md) for the full design.
 
 ## Status
@@ -171,11 +178,45 @@ literal path remains included even when Git ignores it. `[tools.trellis.exclude]
 is a separate post-discovery filter: task and `@release` exclusions do not
 control traversal.
 
+### Manifest adapter
+
+`[tools.trellis.adapter]` redefines the manifest seam for a workspace whose
+members are not Gleam packages. One key is required — `manifest`, the member
+manifest's path relative to the member directory, whose presence marks a member
+and whose extension (`.toml`, `.json`, `.yaml`, `.yml`) picks the format:
+
+```toml
+# trellis.toml at the repo root — an adapter workspace usually has no
+# gleam.toml for the table to live in, so trellis accepts this file too.
+# Root discovery prefers it; carrying the table in both is an error.
+[tools.trellis]
+members = ["plugins/*"]
+
+[tools.trellis.adapter]
+manifest = ".claude-plugin/plugin.json"
+# name = "name"        # dotted field paths, defaults shown
+# version = "version"  # this is the field `version apply` rewrites
+
+[tools.trellis.publish]
+package_tags = ["exact", "major"]
+```
+
+The bump is surgical: only the field `version` names is rewritten, so comments,
+key order, and formatting survive byte for byte. The changelog engine,
+`version`, `tag`, GitHub Releases, `release pr`, and `ci` are unchanged.
+
+The graph is flat — an adapter declares no dependency edges, so nothing ripple-
+bumps. `publish.lifecycle` defaults to `git_only` and `hex` is a configuration
+error; `publish`, `lockfile refresh`, `new`, and `run`'s built-in Gleam verbs
+are refused. `doctor` drops the `manifest.toml`, shared-dependency, and
+toolchain checks, and adds that every member manifest declares a semver version
+and a name matching its directory.
+
 ## Commands
 
 Every command works from anywhere inside the workspace (the root is found by
-walking up to the first `gleam.toml` with a `[tools.trellis]` table, like
-`git` or `cargo` — member manifests along the way are skipped). Without a
+walking up to the first `trellis.toml` or `gleam.toml` with a `[tools.trellis]`
+table, like `git` or `cargo` — member manifests along the way are skipped). Without a
 `[tools.trellis]` table anywhere, the git repository root is the workspace
 root and members are auto-discovered.
 

docs/DESIGN.md

@@ -294,6 +294,58 @@ Notably absent, because derived: package lists, dependency order, per-package
 changelog wiring, version-file maps, path-dep rewrite maps, tag→package
 mappings.
 
+### 4.2 The manifest seam
+
+Trellis reads exactly four things out of a member's manifest:
+
+1. **Membership** — the file's presence is what makes a directory a member.
+2. **Identity** — its name.
+3. **Version** — the field a bump rewrites.
+4. **Dependency edges** — path deps, which become the graph.
+
+Everything else trellis does is computed from those four, and is therefore
+language-agnostic: the changelog engine, `version plan`/`apply`, exact and
+series tags, GitHub Releases, `release pr`, the scheduler, `ci matrix` and
+`ci outputs`. The `git_only` lifecycle already *is* the publishing model for a
+registry-less package type — changelog → version → tag → GitHub Release.
+
+`[tools.trellis.adapter]` redefines the first three for a different manifest
+format, and deliberately leaves the fourth undefined:
+
+```toml
+[tools.trellis.adapter]
+manifest = ".claude-plugin/plugin.json"   # membership; extension picks format
+name = "name"                             # identity, dotted field path
+version = "version"                       # bump target, dotted field path
+```
+
+No `deps` key means a flat graph, and every consumer of the graph degrades
+cleanly rather than specially: topological order is member order, ripple bumps
+never fire, and the path-dep rewrite is unreachable. That is the whole reason
+the adapter is four keys rather than a subsystem — declaring dependency edges
+in an arbitrary manifest format is the expensive half, and no motivating
+repository needs it yet.
+
+Two consequences follow from the seam rather than from configuration. A
+workspace whose members are not Gleam packages usually has no `gleam.toml` for
+the `[tools.trellis]` table to live in, so a root `trellis.toml` is a second
+config home, preferred over `gleam.toml` when both exist and an error when both
+carry the table. And the lifecycle ladder tops out one rung lower: `hex` under
+an adapter is a configuration error, not a runtime refusal, so it is caught
+once at load rather than at each of `publish`'s four gates.
+
+The write side is where the seam costs something real. A `gleam.toml` bump has
+always been surgical — `toml_edit` with the original value's decor cloned onto
+the replacement — because a manifest is a file its owner reads. That promise
+has to hold for JSON and YAML too, and neither has a `toml_edit`. `src/manifest.rs`
+gets it from the fact that YAML 1.2 is a strict superset of JSON: one
+`saphyr-parser` event walk locates the target scalar's span in both formats,
+and the edit is a byte splice. Two of that parser's guarantees do not survive
+contact — `Marker::index` is a char index despite its doc comment, and a quoted
+scalar's `span.end` in block context runs to end-of-line, comment included — so
+only the start marker and the scalar style are trusted, and the extent is
+re-lexed from there.
+
 ## 5. Command surface
 
 ### Introspection

src/changelog.rs

@@ -711,17 +711,6 @@ fn civil_from_days(days: i64) -> (i64, u32, u32) {
     (if month <= 2 { year + 1 } else { year }, month, day)
 }
 
-pub fn render_manifest_version(text: &str, next: &semver::Version) -> Result<String> {
-    let mut doc: toml_edit::DocumentMut = text.parse().context("failed to parse gleam.toml")?;
-    let Some(value) = doc.get_mut("version").and_then(|item| item.as_value_mut()) else {
-        bail!("gleam.toml has no version field");
-    };
-    let mut replacement = toml_edit::Value::from(next.to_string());
-    *replacement.decor_mut() = value.decor().clone();
-    *value = replacement;
-    Ok(doc.to_string())
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;

src/commands/ci.rs

@@ -61,7 +61,7 @@ pub fn outputs(workspace: &Workspace) -> Result<()> {
         .members
         .iter()
         .filter(|m| m.releasable())
-        .map(|m| format!("{}/gleam.toml", m.rel_path))
+        .map(|m| format!("{}/{}", m.rel_path, workspace.manifest_rel()))
         .collect();
     let tags: Vec<String> = workspace
         .members