# Agent Note: dsh web config-tree boot and the web transport layering

Status: implemented

English | [中文](2026-07-24-web-config-tree-boot-and-transport-layering.zh.md)

> Scope: how `dsh web` composes (cordis.yml + pre-cordis boot classes + config sources) and how the web transport splits across packages (gateway / carrier / binding / graph / dev-reload). The [client plugin loading note](2026-07-23-client-plugin-loading-model.md) owns the browser-side loading chain this composition feeds.

## Problem

`dsh web` was the only hand-assembled surface left: `bootHost` mounted 32 plugins with configs pinned in code (violating no-hardcoded-tunables), the client roster was a `web.ts` constant, and TUI/headless had long been yml compositions. The transport layer misplaced responsibilities to match: the webserver self-described as a dumb carrier yet knew the `__DSH_BOOT__` graph, owned the SSE channel, and hard-coded the `/api/*` prefix; the dev bundle watch lived inside the prod registry behind a `watch?` flag with no lifecycle owner; the graph registry rescanned everything on every `internal/plugin` emission; per-request errors and fatal server errors shared one sink that always exited the process. One user-visible defect rode along: the web path never loaded `$DSH_HOME/.env`, so `DSH_HOME=… dsh web` could not find an API key living there.

## Decision

**Composition is one flat assembled tree.** `apps/cli/config/base.cordis.yml` plus `apps/cli/config/web.cordis.yml` holds every row — the host runtime (32 rows), the `api-gateway` row, the `webserver` row, and the `dshClient` rows (the browser roster; the modules row is simultaneously a host row). No spine bundle: every plugin is one row and every config field is yml-editable. That stance later became repository-wide, with the rows both surfaces share factored into `apps/cli/config/base.cordis.yml` and each surface reduced to an overlay ([shared-base overlays](../simplification/2026-07-29-shared-base-config-overlays.md)). `--dev` appends the `dsh-client-hmr` row in code before the settle audit — prod and dev differ by exactly that row. Row order carries no load semantics; activation is service-availability driven. The shared audit rejects imports with no fiber, awaits only failed fibers to recover original activation errors, and reports services that leave a fiber `PENDING`; before throwing, it marks those exact rejection reasons through one process checkpoint so `installFailLoud` coalesces Loader's duplicate notification while unrelated unhandled rejections remain fatal. The Node app-boot artifact embeds `@cordisjs/plugin-include` while leaving `@cordisjs/plugin-loader` external, so the include's `EntryTree` and the host bind to one Loader peer instead of splitting a config tree across two Loader implementations.

**Boot glue is a class pair.** `AppCLIEntry` (apps/cli) and `AppWebEntry` (the shell kernel) hold only what must exist independently of cordis: argv facts, the composed patch set, the parsed boot manifest, the module system instance, loading-page handles — everything else lives in plugins. `AppCLIEntry.run()` is three stages: layered env (ambient > cwd `.env` > `$DSH_HOME/.env`, closing the defect above) → patch composition → Loader include boot plus the activation audit. `AppWebEntry.run()` mirrors it browser-side: parse `window.__DSH_BOOT__` into a `BootManifest` (two views: npm-package rows for the module table, cordis-plugin rows for entry composition; malformed wire throws), build the module system, render the loading page, prefetch the `immediately` tier in parallel with Context/Loader setup, **await the prefetch before creating entries** (materialization is `tree.import`'s synchronous require, unprotected by fiber inject waiting; cross-package require edges such as i18n → runtime/client need every immediately-tier factory registered first — an empirically found 10–25% boot race otherwise), adopt the modules entry, create the graph rows, settle, sweep.

**Config sources have one declaration place each.** yml static values are engineering defaults; the profile json (`./.dsh-tmp-profile/config.json`, read-only, never created, cwd-anchored until the `$DSH_HOME` migration) is user config mapped through a static `PROFILE_MAPPINGS` table onto target rows (`provider`/`model` → the `api-gateway` row, `persistenceRoot` → the jsonl row); CLI flags map onto the `webserver` row with a field set disjoint from the json's; env values enter through yml `!!js` expressions, never through the mapping table. Patches replace a row's config wholesale, so the entry class re-reads the yml row's static values (bypass parse) and merges overrides on top. An unmapped json key fails loud. The resolved frontend `distIndex` rides the same patch channel — an assembly fact, not user config.

**The transport splits five ways.** `dsh-host-apiproxy` upgraded to the gateway plugin (`api-gateway` row): default-exports `ApiProxyService`, config `{provider, model}`, provides `ctx.apiProxy`, transport-agnostic and registers no routes — `createApiProxy` moved here from the retired runtime package. `dsh-host-webserver` shrank to a plain route-registration plugin: `HttpServerService` provides `ctx.httpServer` (`register(route) → disposer` with duplicate-pattern throw, `tapIndex` transforms applied in registration order, `port`), listens on activation, per-request failures answer 400 and log without exiting, and knows no harness concepts. The connection node half owns the binding: it injects both services and registers `toFetchHandler(ctx.apiProxy)` under the `/api` prefix — future IPC carriers swap connection's transport while the gateway stays untouched. The modules node half (`ClientModuleHostService`, providing `ctx.clientModuleHost`) owns the graph: incremental per-package scanning (no full-rescan code path — `internal/plugin` marks the fiber's entry name dirty, a flush reconciles each name against live entries, package metadata including negative verdicts is cached forever, re-hashing is reachable only through `rebuilt(id)`), the bundle route, the index tap, and `onRebuilt`/`onGraphChanged` notification. The hmr node half owns dev reload: `fs.watchFile` stat-polling driven by `onGraphChanged` membership, and the `/plugins/events` SSE route.

**Package export discipline.** The modules package exposes exactly `.` (node half) and `./client` (the complete browser half: `ClientModuleSystem`, `parseBootManifest`, the adoption plugin face) — no bespoke subpaths; wire types re-export through the root for host-side consumers. The adoption handshake: the kernel writes the constructed instance to `window.__DSH_MODULES__` before cordis exists; the `./client` apply reads the slot (missing = loud throw) and provides `ctx.modules`.

## Consequences

- Recomposing a web deployment is a yml/patch edit; the retired pieces (`mountWebPlugins`, `CLIENT_PACKAGES`, `createHostWebPluginRegistry`, `startWebServer`, the webserver's graph/SSE/api knowledge) are deleted.
- Headless boots the same composition through the same entry (landed in the stacked follow-up): port 0 is its only surface difference, the model face gains `ask_user_question`/workspace context/model titles per the unification ruling, and `bootHost`/`startHost` retired with the `dsh-host-runtime` package. The profile write path, the `$DSH_HOME` profile relocation, and IPC carriers remain recorded deferrals.
- A TypeScript pitfall worth remembering: a `declare module 'cordis'` augmentation in a file with **no cordis import** is demoted to a standalone module declaration and silently shatters the program-wide `Context` merge (`ctx.on`/`ctx.effect` vanish across the program). Anchor with `import type {} from 'cordis'`.

## Alternatives considered

| Rejected | One-line reason |
|---|---|
| Dedicated `dsh-host-profile` receiver package | The profile json is consumed at patch time; the only runtime consumer of `{provider, model}` is the gateway itself — its config is the receiver |
| Runtime `assembly` shim plugin providing an `apiHandler` service | Existed only because `createApiProxy` lived in runtime; moving it into apiproxy made the gateway self-hosting, and `toFetchHandler` is a pure function the binding side calls |
| Full-rescan + incremental scan coexisting | Two implementations, two semantics; the single per-package path covers the activation pass too |
| A bespoke `./impl` export on the modules package | Non-uniform export surface; the standard `./client` carries the whole browser half |
| dev overlay / `cordis.dev.yml` | One yml; `!!js` cannot conditionalize row existence, and `--dev` appending one row is the entire difference |
| env vars in the mapping table | The same field would gain env/json double sourcing and need an invented precedence |
| Unbarriered create-after-prefetch (`arrive()` dedup as safety) | Disproved by a 10–25% boot race: in-flight dedup covers same-package double-fetch, not cross-package synchronous require edges |
| json file used directly as loader patches | json keys would couple to yml row structure; profile writers would need cordis knowledge |
