mcp/CHANGELOG.md

# Changelog — einherjar/mcp

All notable changes to this module are documented here.
Format follows [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
This module adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

---

## [1.1.1] — 2026-08-07

Patch. `check_env` gains struct-level granularity so it can catch dead vars that module
granularity cannot.

### Added

- **`check_env` `composes` input** — declare the exact config structs an app composes as
  `module/subpackage/Struct` selectors (e.g. `web/server/Config`, `db-postgres/Config`,
  `core/logz/Config`), alongside or instead of the coarse `modules` list. A var counts as
  composed when any listed module or struct declares it.

### Changed

- **`not-composed` now reasons over the composed var set, not just modules.** With struct
  selectors, `check_env` flags struct-level dead vars — e.g. `EINHERJAR_SERVER_CORS_ORIGINS`
  (which lives on `web.Config`) is now reported dead when the app composes `web/server/Config`
  rather than `web.Config`. Passing coarse `modules: ["web"]` keeps the previous behavior.

## [1.1.0] — 2026-08-07

Minor release. The env-var story is now **derived from the framework's real struct tags** end
to end: a tool to read the truth, `.env.example` generated from it, and a rule that rejects
invented names. Also folds in the scaffold-symbol fixes that were staged as v1.0.1 (never
tagged separately). The generated scaffold compiles clean against einherjar v1.0.0.

### Added

- **`get_config_env` tool.** Lists the real environment variables a component config reads —
  name, declaring module/struct/field, `required`, and default — parsed from the indexed
  struct tags (`internal/envspec`). The single source of truth for which `EINHERJAR_*` vars
  exist; no hand-maintained list to drift.
- **`check_env` tool.** Checks a `.env` / `.env.example` against the framework: flags
  `EINHERJAR_*` names that don't exist (e.g. `EINHERJAR_PG_DATABASE`), required vars missing
  for the modules an app composes, and vars set for a module it does not compose (dead vars,
  the way `EINHERJAR_SERVER_CORS_ORIGINS` is inert unless you compose `web.Config`).
- **`config.unknown-env-var` rule** (now twelve). `validate_snippet` rejects any struct field
  tagged `env:"EINHERJAR_*"` whose name the framework does not declare — the exact class of
  drift that shipped `EINHERJAR_PG_DATABASE` / `_SERVER_ADDR`. The valid-name set is injected
  from the index at startup, so the rule can never drift from the real tags.

### Changed

- **`get_scaffold` now derives `.env.example` from the index** instead of a hand-written
  string. Required vars (no default) are emitted uncommented with a runnable dev value;
  defaulted vars are emitted commented, documenting the framework default. Names and defaults
  can no longer drift from the modules the scaffold composes (`core/logz` + `web/server` +
  `db-postgres`).
- **The scaffold composes `logz.Config`** instead of hard-coding the logger, so
  `EINHERJAR_LOG_LEVEL` / `_JSON` are live and documented rather than silently ignored.
  Verified end to end: `env.Parse` loads `slog.Level` from `EINHERJAR_LOG_LEVEL`. (Log format
  is now env-driven; set `EINHERJAR_LOG_JSON=true` in production.)
- **The `wire` builtin routes the incremental flow to the new tools.** Composing a component
  later now points at `get_config_env("<module>")` for its exact vars and `check_env` to
  confirm `.env.example` is complete — and spells out the split between framework `EINHERJAR_*`
  (discoverable, name-checked) and app-owned `APP_*` (your discipline).

### Fixed

- **`logz.Logger` → `logging.Logger`.** The logger interface is `contracts/logging.Logger`;
  `logz.New` returns it. The scaffold's health hook and the `wire` builtin's `withUsers`
  example typed loggers as the non-existent `logz.Logger`.
- **`postgres.Component` → `postgres.Provider`** in hook signatures. `postgres.New` returns a
  `Component` (a lifecycle component that embeds `Provider`); hooks and `NewUnitOfWork` take a
  `Provider`.
- **The real env tags throughout:** `EINHERJAR_SERVER_ADDR` → `EINHERJAR_SERVER_HOST` +
  `_PORT`, and `EINHERJAR_PG_DATABASE` → `EINHERJAR_PG_NAME` (plus `EINHERJAR_PG_SSL_MODE`).
- The scaffold's minimal health hook no longer takes unused `logger`/`db` parameters.

## [1.0.0] — 2026-08-07

The MCP reaches **v1.0.0**, aligned with the v1.0.0 framework. The headline is the
canonical application **scaffold**: the one opinionated starting point so an AI no longer
hand-rolls `main.go` and the launcher when creating a service from zero.

### Added

- **`get_scaffold` tool.** Returns the canonical minimum application scaffold as
  ready-to-write files, with import paths filled from a `module` argument: a clean `main.go`
  (godotenv autoload + `wire.Run()`), `internal/wire/wire.go` (the launcher assembly), a
  composed `internal/config/config.go`, a health feature hook, and `.env.example`.
- **Three `validate_snippet` rules** (now eleven total), with a rules test suite:
  `main.dirty` (the launcher/components built in `main` instead of `internal/wire`),
  `main.no-godotenv-autoload` (a wire-convention `main` that never loads `.env`), and
  `config.raw-getenv` (reading a framework `EINHERJAR_*` var via `os.Getenv` instead of
  composing the component's `Config` type).
- **Config conventions in the `wire` builtin.** A `Config` section (compose the framework's
  component configs, load with `caarlos0/env`, `APP_*` for app-owned fields, `EINHERJAR_*`
  for framework ones) and a **Config & .env.example** section: every env var the config
  reads must also be documented in `.env.example`, kept in lock-step.

### Changed

- **`wire` builtin re-synced to the current gold standards** (`iron-dough-api`, `pei-api`):
  `main.go` now shows the `_ "github.com/joho/godotenv/autoload"` blank import (previously
  omitted, so the AI produced a `main` that never loaded `.env`); the assembly file is
  `wire.go` (was `launcher.go`).
- **Version alignment.** The README badge and `serverVersion` were stale at `v0.1.0`; both
  now read `v1.0.0`.

### Removed

- **Migrations and seeding from the `wire` builtin.** How migrations run and how the first
  admin is seeded (via code, a DB team, an endpoint, a webhook, …) is the developer's
  choice — it belongs to no Einherjar module and is not a hard convention, so it is out of
  the scaffold and the documented conventions.

## [0.2.0] — 2026-06-10

Minor release. The indexer now captures the *members* of composite types, closing a gap where `get_symbol` and `search_symbols` could name a struct or interface but not describe its shape — most painfully, struct tags (env-var keys, json names) were invisible.

### Added

- **Struct fields in the index.** Each struct-type symbol now carries a `fields` array — field name, type, raw struct tag (backticks stripped), doc comment, and an `embedded` marker. `get_symbol` returns it; previously the signature was truncated to the bare `type X struct` header, so field names, types, and tags (e.g. `env:"EINHERJAR_PG_HOST"`) were dropped entirely.
- **Interface method sets in the index.** Each interface-type symbol now carries a `methods` array — method name, signature (without the leading `func`), and doc comment, including embedded interfaces. Consumers can now see what a port like `db-postgres` `Provider` actually requires.
- **Search by field/tag/method.** `search_symbols` now also matches a query against struct field names, field types, and struct tags, and against interface method names/signatures — so an env-var key or a method name resolves to the type that declares it.
- **`internal/index` test suite** covering field, tag, embedded-field, interface-method, and search-by-tag capture (the package previously had no tests).

### Notes

- The index schema gains two optional (`omitempty`) fields; `SchemaVersion` is unchanged because the change is additive and older consumers parse the new index unchanged.
- This is a pure indexer/schema change. The live server picks it up on its next image build, which re-runs `cmd/indexer` (see `Dockerfile`). A deployment that has not been rebuilt will still serve the older, member-less index.

---

## [0.1.1] — 2026-05-29

Patch release. Two changes to `cmd/server` make the binary cleaner to run behind a unix socket on a reverse-proxied host, plus two repository-hygiene changes that follow from the same deployment exercise.

### Added

- **Systemd socket activation** in `cmd/server`. The binary inherits the listener from `LISTEN_FDS` via `github.com/coreos/go-systemd/v22/activation` when present, falling back transparently to TCP `-addr` binding otherwise. Startup log records `"mode":"socket-activated"` or `"mode":"tcp"`. Same binary, no flag or env var to toggle.

### Changed

- **Health probe path** moved from `/healthz` to `<path>/healthz` (default `/mcp/healthz`). Lets a reverse proxy expose the entire MCP service through one location prefix. v0.1.0 consumers hitting the old `/healthz` route receive 404; update to `/mcp/healthz` (or whatever path matches your `-path` flag).
- **`README.md` deployment section** rewritten to be hosting-agnostic. Points at the `Dockerfile` and systemd socket activation as supported binary modes without prescribing one operator's setup. Adds the SSE-buffering caveat once: any reverse proxy must disable response buffering on the `/mcp` location, otherwise Server-Sent Events get batched and streamable MCP sessions break.
- **`/deploy/`** is now `.gitignored`. Local deployment artefacts (systemd units, reverse-proxy templates, per-release scripts) are operator-specific by design and live outside the public repository. The `Dockerfile` at the module root remains the only portable, public-facing build artefact.

### Dependencies

- **Added:** `github.com/coreos/go-systemd/v22 v22.7.0` — used by `cmd/server` to detect and use a systemd-passed listener.

### Upgrade notes

| If you… | Action |
|---|---|
| Consume the MCP service from an MCP client (Claude, Cursor, Zed, etc.) | None — `/mcp` is unchanged |
| Monitor the service via the healthz probe | Update the probe URL from `/healthz` to `/mcp/healthz` |
| Run the binary directly (no reverse proxy) | None — `-addr` TCP binding still works the same way |
| Run the binary under systemd with a socket unit | The same binary now picks up the inherited listener automatically |

---

## [0.1.0] — 2026-05-29

Initial release. The `mcp` module hosts the **Einherjar Model Context Protocol server** — a remote, streamable-HTTP service that teaches AI assistants about every other module of the framework.

### Added

#### Server (`cmd/server`)

- Streamable-HTTP MCP server built on `github.com/modelcontextprotocol/go-sdk` v1.0.0
- Listen address and HTTP path configurable via `EINHERJAR_MCP_ADDR` (default `:8080`) and `EINHERJAR_MCP_PATH` (default `/mcp`)
- `/healthz` liveness endpoint
- Embedded framework index loaded once at startup; in-memory for the lifetime of the process

#### Indexer (`cmd/indexer`)

- Walks an Einherjar repository checkout and produces `data/index.json`
- For each sibling module captures: import path, Go version, README (full + extracted tagline), CHANGELOG, root `doc.go` package comment, sub-package doc comments, every exported symbol (type/interface/func/method/const/var) with signature + godoc, ADRs, README code-fence examples, dependency edges from `go.mod`, and the contents of `compliance_test.go` (interface assertions + structural test names)
- Appends a synthetic `wire` module documenting canonical Einherjar application wiring conventions

#### Tools (10)

- `list_modules` — enumerate every Einherjar module with purpose and sub-packages
- `get_module` — package doc, dependencies, sub-packages, key symbols, ADRs, compliance counts; optional embedded README
- `search_symbols` — full-text search across name, doc, sub-package, module
- `get_symbol` — full signature, doc, and source location for one symbol
- `list_adrs` — list architectural decision records, optionally filtered by module
- `get_adr` — fetch one ADR's markdown body
- `get_example` — canonical usage snippets extracted from module READMEs and the `wire` conventions
- `get_compliance` — interface assertions and structural test names from a module's `compliance_test.go`
- `get_changelog` — full CHANGELOG.md markdown for one module
- `validate_snippet` — pattern-match a Go snippet against framework conventions; returns findings with severity, hint, and line

#### Validation rules (8)

- `launcher.missing-run`, `launcher.no-components`, `launcher.run-error-discarded`
- `logz.direct-env-read`
- `web.server-not-appended`
- `wire.hook-bad-signature`, `wire.hook-outside-beforestart`, `wire.route-specific-after-param`

#### Synthetic `wire` module

- Authored in `internal/index/builtins/README.md`; participates in `list_modules`, `get_module`, and `get_example` exactly like a real module
- Sections: project layout, `Run()` shape, feature hook shape, route ordering, authorization, middleware helpers, adapters at the wire boundary, migrations and seeds
- All examples use einherjar import paths

#### Packaging

- Multi-stage `Dockerfile` that builds from the einherjar repository root (`docker build -f mcp/Dockerfile .`) so the indexer can walk every sibling module at image-build time
- Distroless runtime image; static binary; non-root user