diff --git a/plugins/markdown-format/.claude-plugin/plugin.json b/plugins/markdown-format/.claude-plugin/plugin.json
index 78efab998..b4a8bb2f0 100644
--- a/plugins/markdown-format/.claude-plugin/plugin.json
+++ b/plugins/markdown-format/.claude-plugin/plugin.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://json.schemastore.org/claude-code-plugin-manifest.json",
   "name": "markdown-format",
-  "version": "0.4.1",
+  "version": "0.5.0",
   "description": "Auto-format and lint Markdown on edit via markdownlint-cli2, using the consuming repo's own markdownlint config.",
   "author": {
     "name": "Melodic Software",
diff --git a/plugins/markdown-format/CHANGELOG.md b/plugins/markdown-format/CHANGELOG.md
index 202213115..b1d4ab373 100644
--- a/plugins/markdown-format/CHANGELOG.md
+++ b/plugins/markdown-format/CHANGELOG.md
@@ -3,6 +3,21 @@
 All notable changes to the `markdown-format` plugin are documented here. Format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); this plugin uses semantic versioning.
 
+## [0.5.0]
+
+### Added
+
+- **`setup` skill on the uniform contract** (fleet conformance wave, dim 8 —
+  the fleet's first conforming exemplar). `check` verifies the hook's runtime
+  prerequisites read-only (Bash, `jq`, `markdownlint-cli2` resolution,
+  discovered markdownlint config + trust boundary, effective toggle);
+  `apply` re-checks and resolves — guidance for system tools and the native
+  toggle, and an explicitly requested `apply install-lint` as its only write
+  path: `markdownlint-cli2` added as a dev dependency via the repository's own
+  package manager (npm, pnpm, Yarn, or Bun, resolved from the repo's lockfile
+  and `packageManager` field).
+  Non-interactive when the action argument is supplied.
+
 ## [0.4.1]
 
 ### Changed
diff --git a/plugins/markdown-format/README.md b/plugins/markdown-format/README.md
index 28d3fd04b..3ca7f3714 100644
--- a/plugins/markdown-format/README.md
+++ b/plugins/markdown-format/README.md
@@ -17,9 +17,10 @@ imposes no rules of its own.
   reported via `additionalContext`; they never reject the edit. Make a commit
   hook or CI your hard gate.
 - **Config from the consumer.** `markdownlint-cli2` discovers config
-  (`.markdownlint-cli2.jsonc`, `.markdownlint.json`, …) by walking up from the
-  repository root. The hook `cd`s to that root before linting so the right
-  cascade applies regardless of the session's working directory.
+  (`.markdownlint-cli2.jsonc`, `.markdownlint.json`, …) per edited file, from
+  the file's directory up through its parents — so a nested config governs its
+  subtree. The hook `cd`s to the repository root before linting so that
+  discovery caps at the root regardless of the session's working directory.
 
 ## Requirements
 
@@ -63,6 +64,12 @@ the advisory to appear again.
 /plugin install markdown-format@melodic-software
 ```
 
+Then verify the runtime prerequisites with `/markdown-format:setup check`;
+`/markdown-format:setup apply` resolves anything the check reports with
+guidance, and `/markdown-format:setup apply install-lint` additionally
+authorizes installing `markdownlint-cli2` as a dev dependency using the
+repository's own package manager.
+
 ## Configuration
 
 The rules themselves are never configured here — the plugin's only rule source is
diff --git a/plugins/markdown-format/skills/setup/SKILL.md b/plugins/markdown-format/skills/setup/SKILL.md
new file mode 100644
index 000000000..251a8dcd8
--- /dev/null
+++ b/plugins/markdown-format/skills/setup/SKILL.md
@@ -0,0 +1,89 @@
+---
+name: setup
+description: "Verify the markdown-format hook's runtime prerequisites and configuration for this repository. Use when: 'set up markdown-format', 'configure markdown-format', 'is markdown-format working', formatting silently isn't happening, or the hook reported a missing prerequisite. Actions: check (read-only verification, default) | apply (resolve what check found). Re-runnable and safe."
+argument-hint: "check | apply [install-lint]"
+user-invocable: true
+disable-model-invocation: true
+---
+
+## Purpose
+
+Thin check-centric setup per the uniform contract: `check` inspects and reports, `apply`
+resolves. This plugin owns no consumer-project configuration — rules come from the
+repository's own markdownlint config, and the only tunable is the native `userConfig`
+toggle — so `apply` is guidance-and-verify, with exactly one write path: the explicitly
+invoked `apply install-lint` dependency install described below.
+
+Action routing: no argument or `check` runs the check; `apply` runs the check first, then
+remediation; `apply install-lint` additionally authorizes the consumer-repo dependency
+install described below. All are non-interactive — never prompt when the action is given.
+
+## `check` (read-only)
+
+The hook script (`${CLAUDE_PLUGIN_ROOT}/hooks/markdown-format.sh`) is the single source of
+truth for what it requires and how it resolves things. **Read it first** — probe what it
+actually does, don't recite this file. Then run each probe via Bash and report a
+PASS/FAIL/INFO table with one remediation line per FAIL. Do not modify anything.
+
+1. **Bash version** — check against the hook's documented floor (README Requirements),
+   noting any features the hook degrades without (for example telemetry's Bash builtin).
+2. **`jq`** — `command -v jq`. FAIL if absent: the hook then skips with a visible
+   once-per-session notice instead of formatting.
+3. **`markdownlint-cli2`** — resolve it exactly the way the hook's resolution code does
+   (its sanctioned lookup paths, including its symlink/escape validation of a repo-local
+   shim). A binary or shim the hook would reject must not PASS here. Then confirm the
+   resolved tool actually executes — run it with `--version` (a repo shim can resolve yet
+   still be broken: missing Node interpreter, dangling target); resolution without
+   successful execution is FAIL, with the execution error in the remediation line. FAIL
+   when nothing the hook would accept resolves.
+4. **Consumer markdownlint config** — mirror the hook's config walk: it loads configs from
+   an edited file's directory up to the repo root, so nested configs apply to nested files.
+   Search the whole tree (skip `node_modules`), report the root config the cascade
+   discovers (or INFO that none exists — tool defaults then apply), list nested configs
+   with their directory scope, and surface the README's configuration trust boundary for
+   every config the hook's own risk collection (`collect_risky_configs`) would flag.
+5. **Hook toggle** — report the effective `markdown_format_enabled` value:
+   `${user_config.markdown_format_enabled}` (unexpanded or empty means default `true`).
+6. **Hook registration** — INFO: confirm the plugin is enabled for this project
+   (`/plugin` → Installed) rather than parsing settings files.
+
+## `apply` (idempotent)
+
+Run `check`, then for each FAIL offer the resolution — never install anything without the
+consumer's explicit go-ahead in the invocation. `apply install-lint` adds
+`markdownlint-cli2` as a dev dependency in the consumer repository **using the
+repository's own package manager**, resolved in order: lockfile (`pnpm-lock.yaml` →
+`pnpm add -D`, `yarn.lock` → `yarn add -D`, `bun.lock`/`bun.lockb` → `bun add -d`,
+`package-lock.json` or `npm-shrinkwrap.json` → `npm install --save-dev`), then the
+`package.json` `"packageManager"` field when no lockfile exists, then npm only when
+neither signal is present. With no `package.json`, an ambiguous multi-lockfile state, or a lockfile that
+contradicts `packageManager`, stop with manager-specific guidance instead of guessing —
+never introduce a competing lockfile. The change is stated before running. For a Yarn repository, don't infer the linker — ask
+the repo's own Yarn: run `yarn config get nodeLinker` in the repo. `pnp` (Berry's default
+when unset) → skip the install and give guidance, because Plug'n'Play generates a loader file,
+not the `node_modules/.bin` shim the hook resolves; install `markdownlint-cli2` on
+`PATH` or switch the linker. `node-modules`/`pnpm`, or Yarn Classic (which has no such
+setting and always materializes `node_modules`) → install. The
+verify-after-remediation rule below is the backstop when an install still yields no
+usable shim. After ANY remediation, re-run the
+relevant `check` probe and report its actual result — never claim resolved on the
+install command's exit code alone. For everything else `apply` only points:
+
+- missing `jq` / Bash: platform install instructions from the README Requirements section;
+  this skill never installs system packages.
+- toggle off: direct to `/plugin configure markdown-format` or
+  `claude plugin install markdown-format@<marketplace> --config markdown_format_enabled=true`;
+  this skill never writes user settings or `pluginConfigs`.
+- no markdownlint config: offer to create a minimal `.markdownlint-cli2.jsonc` in the
+  repository root only when explicitly asked — the plugin imposes no rules of its own.
+
+Re-running `apply` after everything passes changes nothing and reports "already configured".
+
+## What this skill does NOT do
+
+- Run the formatter — editing any `.md` file exercises the hook end-to-end. The only
+  execution `check` performs is the harmless `--version` liveness probe of the resolved
+  linter; it never lints, fixes, or touches repository content.
+- Write the plugin cache, Claude Code user settings, or `pluginConfigs`.
+- Download anything during `check`; network use happens only in an explicitly
+  requested `apply install-lint` inside the consumer repository.