diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 62d6f36..391e3db 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -11,7 +11,11 @@ name: Release (public npm)
 #                    PACKS the real tarball, installs it into a throwaway
 #                    project, and imports it -- root AND the ./sdk-server
 #                    subpath. ESM only: this package ships no `require`
-#                    condition, so a CJS arm would be a false failure.
+#                    condition, so a CJS arm would be a false failure. The
+#                    smoke then type-checks the installed tarball from the
+#                    CONSUMER's side (#77): root without the optional peer
+#                    dependency, ./sdk-server with it. Shipping a .d.ts is not
+#                    the same claim as shipping one that resolves.
 #   3. publish     — only after 1+2 pass. The tag version MUST equal
 #                    package.json version, and the npm dist-tag is derived from
 #                    the version: any prerelease -> `next`, stable -> `latest`,
@@ -208,6 +212,82 @@ jobs:
             }
             console.log('types ok:',[...targets].join(', '));"
 
+          # -------------------------------------------------------------------
+          # Consumer-side TYPE RESOLUTION (#77).
+          #
+          # The check above proves the .d.ts files are IN the tarball. It does
+          # not prove they RESOLVE, and only the second is something a consumer
+          # experiences. `dist/sdk-server.d.ts` references a type from
+          # @anthropic-ai/claude-agent-sdk, which is an OPTIONAL peer, so the
+          # existence check would stay green on a package that fails to
+          # type-check for anyone who did not install that peer.
+          #
+          # Decision (a) on #77: requiring the peer to type-check ./sdk-server
+          # is honest -- that subpath exists to build a config for the Agent
+          # SDK, so a consumer using it has the SDK by definition. The contract
+          # this gate enforces is therefore:
+          #
+          #   root         must type-check WITHOUT the optional peer
+          #   ./sdk-server must type-check WITH it
+          #
+          # It deliberately does NOT assert that ./sdk-server fails without the
+          # peer. That would freeze today's behaviour into the gate and turn a
+          # future switch to self-contained declarations (option (b)) into a
+          # spurious release failure.
+          #
+          # Each arm gets its own throwaway project so its install shape is
+          # exactly what it claims to test -- re-running `npm install --no-save`
+          # in the smoke dir above would rebuild that tree from its (empty)
+          # package.json and could drop the tarball itself.
+          # -------------------------------------------------------------------
+          cd "$GITHUB_WORKSPACE"
+          # Pin both installs to the versions this repo's lockfile resolves. A
+          # floating `typescript@latest` would let a compiler release nobody
+          # vetted decide whether a publish goes out, and a floating peer could
+          # type-check against a different major than the one we build against.
+          #
+          # Read from package-lock.json, NOT `require('<pkg>/package.json')`:
+          # @anthropic-ai/claude-agent-sdk ships an `exports` map with no
+          # "./package.json" entry, so requiring its manifest as a subpath
+          # throws ERR_PACKAGE_PATH_NOT_EXPORTED -- the same trap the bin check
+          # above already documents for this package. And a package missing
+          # from the lockfile fails here rather than silently becoming an empty
+          # version string that installs whatever `latest` happens to be.
+          LOCKED="$(node -e "
+            const lock=require('./package-lock.json');
+            const pick=n=>{
+              const e=(lock.packages||{})['node_modules/'+n];
+              if(!e||!e.version){
+                console.error('::error title=version not pinned in lockfile::'+n+' has no resolved version in package-lock.json - refusing to install a floating version into the release gate');
+                process.exit(1);
+              }
+              return e.version;
+            };
+            process.stdout.write([pick('typescript'),pick('@types/node'),pick('@anthropic-ai/claude-agent-sdk')].join(' '));
+          ")"
+          read -r TSC_VERSION TYPES_NODE_VERSION PEER_VERSION <<< "$LOCKED"
+          echo "type-resolution arms: typescript@$TSC_VERSION, @types/node@$TYPES_NODE_VERSION, optional peer @anthropic-ai/claude-agent-sdk@$PEER_VERSION"
+
+          # ARM 1 — the plain consumer: the tarball and nothing else. @types/node
+          # is a stand-in for the ambient environment any Node consumer has, not
+          # a dependency of ours; see tsconfig.base.json.
+          ARM_ROOT="$(mktemp -d)"
+          cp -R "$GITHUB_WORKSPACE/scripts/smoke/consumer-types" "$ARM_ROOT/typecheck"
+          cd "$ARM_ROOT"
+          npm init -y >/dev/null 2>&1
+          npm install --no-save --ignore-scripts "$TARBALL" "typescript@$TSC_VERSION" "@types/node@$TYPES_NODE_VERSION" >/dev/null 2>&1
+          bash "$GITHUB_WORKSPACE/scripts/smoke/consumer-types/run-arm.sh" \
+            "$ARM_ROOT" tsconfig.root.json "root entry, optional peer NOT installed"
+
+          # ARM 2 — the Agent SDK consumer: the tarball plus the optional peer.
+          ARM_SDK="$(mktemp -d)"
+          cp -R "$GITHUB_WORKSPACE/scripts/smoke/consumer-types" "$ARM_SDK/typecheck"
+          cd "$ARM_SDK"
+          npm init -y >/dev/null 2>&1
+          npm install --no-save --ignore-scripts "$TARBALL" "typescript@$TSC_VERSION" "@types/node@$TYPES_NODE_VERSION" "@anthropic-ai/claude-agent-sdk@$PEER_VERSION" >/dev/null 2>&1
+          bash "$GITHUB_WORKSPACE/scripts/smoke/consumer-types/run-arm.sh" \
+            "$ARM_SDK" tsconfig.sdk-server.json "./sdk-server subpath, optional peer installed"
+
   # ---------------------------------------------------------------------------
   # Gate 3 — publish. Runs ONLY if secret-scan + verify are green.
   #
diff --git a/.gitignore b/.gitignore
index bcd0bfe..b6f1b1f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,13 @@ node_modules
 dist/
 .ts-out/
 *.log
+
+# `npm pack` — which the release smoke runs, and which anyone reproducing it
+# locally will run — drops a publishable tarball in the repo root.
+*.tgz
+
+# Public repo. These have never been committed here; the entries exist so a
+# stray `git add -A` cannot be the first time.
+.env
+.env.*
+.DS_Store
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ed4ce10..d088250 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -179,7 +179,12 @@ tool call — those installs stay broken until `0.2.1` ships and consumers upgra
   optional `@anthropic-ai/claude-agent-sdk` peer dependency, so type-checking
   an import of `@wave-av/mcp-server/sdk-server` without that package installed
   now fails with TS2307 (instead of silently resolving to `any`); install the
-  peer dependency to consume that subpath. (#76)
+  peer dependency to consume that subpath. This is a deliberate choice rather
+  than an accident of the build (see #77): the `./sdk-server` subpath exists to
+  hand a config object to the Agent SDK, so requiring the SDK to type-check it
+  is honest. The release gate now enforces both halves of that contract — the
+  root entry must type-check for a consumer who has NOT installed the peer, and
+  `./sdk-server` must type-check for one who has. (#76)
 
 ### Security
 
diff --git a/scripts/smoke/consumer-types/package.json b/scripts/smoke/consumer-types/package.json
new file mode 100644
index 0000000..9d30dcf
--- /dev/null
+++ b/scripts/smoke/consumer-types/package.json
@@ -0,0 +1,6 @@
+{
+  "name": "wave-mcp-consumer-types-probe",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module"
+}
diff --git a/scripts/smoke/consumer-types/root.ts b/scripts/smoke/consumer-types/root.ts
new file mode 100644
index 0000000..0121254
--- /dev/null
+++ b/scripts/smoke/consumer-types/root.ts
@@ -0,0 +1,18 @@
+// Consumer-side probe for the ROOT entry point.
+//
+// Asks the only question a consumer cares about: installed the published
+// tarball and nothing else, does `@wave-av/mcp-server` resolve its types?
+//
+// `typeof import(...)` is a purely type-level reference -- it forces tsc to
+// resolve `exports["."].types` and check the declarations it reaches, without
+// emitting a runtime import. That matters here: the root entry is the
+// executable (`#!/usr/bin/env node`, calls `server.connect(transport)` at top
+// level), so a real import would start the MCP server and hang.
+// Scope, stated plainly: `dist/index.d.ts` is currently `export {};` — the root
+// entry is an executable with no library surface — so this arm today proves
+// that the root `types` target RESOLVES and nothing beyond it. That is thin
+// because the package is thin at root, not because the check is lax: the moment
+// the root gains an export, tsc follows it, and a reference to the optional peer
+// leaking into a root-reachable declaration fails this arm. Verified by
+// negative control before merge.
+export type Root = typeof import("@wave-av/mcp-server");
diff --git a/scripts/smoke/consumer-types/run-arm.sh b/scripts/smoke/consumer-types/run-arm.sh
new file mode 100755
index 0000000..c19789f
--- /dev/null
+++ b/scripts/smoke/consumer-types/run-arm.sh
@@ -0,0 +1,88 @@
+#!/usr/bin/env bash
+# Run one consumer-side type-resolution arm of the release e2e-smoke.
+#
+#   run-arm.sh <arm-dir> <tsconfig-name> <label>
+#
+# <arm-dir> is a throwaway project that already has the packed tarball
+# installed (plus, for the ./sdk-server arm, the optional peer) and a
+# `typecheck/` copy of this directory.
+#
+# Scope of the failure signal: this gate fails on everything EXCEPT diagnostics
+# located inside a dependency's own declarations under node_modules. Those --
+# and only those -- are downgraded to warnings. tsconfig.base.json turns
+# skipLibCheck OFF -- which is the whole point, it is what makes tsc look
+# inside the tarball's declarations -- but that also makes it visit the
+# declarations of @modelcontextprotocol/sdk and zod. An upstream regression in
+# THEIR .d.ts is not this package's release gate to enforce, and a gate that
+# blocks a release on somebody else's dependency is a gate that gets switched
+# off. Those are reported as warnings instead.
+set -uo pipefail
+
+ARM_DIR="${1:?arm dir required}"
+TSCONFIG="${2:?tsconfig name required}"
+LABEL="${3:?label required}"
+
+# Anchor the pattern on the package directory and on the probe files so a
+# diagnostic inside the tarball is always ours, and one in a sibling package
+# never is.
+readonly OURS_RE='node_modules/@wave-av/mcp-server/|(^|/)(root|sdk-server)\.ts\('
+
+TSC="$ARM_DIR/node_modules/.bin/tsc"
+if [ ! -x "$TSC" ]; then
+  echo "::error title=type-resolution arm cannot run::$LABEL: no executable tsc at $TSC - the arm never type-checked anything"
+  exit 1
+fi
+
+CONFIG="$ARM_DIR/typecheck/$TSCONFIG"
+if [ ! -f "$CONFIG" ]; then
+  echo "::error title=type-resolution arm cannot run::$LABEL: no tsconfig at $CONFIG"
+  exit 1
+fi
+
+OUT="$("$TSC" -p "$CONFIG" --pretty false 2>&1)"
+RC=$?
+
+OURS="$(printf '%s\n' "$OUT" | grep -E "$OURS_RE" || true)"
+
+# Only a diagnostic located INSIDE node_modules is somebody else's to fix. The
+# bucket is an allowlist, not "anything that carries a file location": tsc does
+# report the arm's own mis-wiring with a location, e.g.
+#   tsconfig.base.json(4,5): error TS5023: Unknown compiler option 'foo'.
+# so keying the excuse on "has a location" excused exactly the setup errors that
+# mean the arm type-checked nothing -- it warned, left GLOBAL empty, and exited
+# 0 with "type resolution ok" (same for TS5024/TS6046/TS5012). Default is now
+# fatal: a line is excused only if it names a path under node_modules.
+# node_modules/ is anchored to a directory boundary so a sibling directory that
+# merely ends in the name -- my-node_modules/app.ts(1,1) -- is not excused.
+readonly DEP_DIAG_RE='^([^(]*/)?node_modules/[^(]*\([0-9]+,[0-9]+\): error TS'
+OTHERS="$(printf '%s\n' "$OUT" | grep -vE "$OURS_RE" | grep -E "$DEP_DIAG_RE" || true)"
+GLOBAL="$(printf '%s\n' "$OUT" | grep -vE "$OURS_RE" | grep -E 'error TS' | grep -vE "$DEP_DIAG_RE" || true)"
+
+if [ -n "$OTHERS" ]; then
+  COUNT="$(printf '%s\n' "$OTHERS" | wc -l | tr -d ' ')"
+  echo "::warning title=type errors outside this package ($LABEL)::$COUNT diagnostic(s) in dependencies' declarations, not in @wave-av/mcp-server - not failing the release on them"
+  printf '%s\n' "$OTHERS" | head -n 20
+fi
+
+if [ -n "$OURS" ]; then
+  echo "::error title=$LABEL does not type-check for a consumer::the tarball ships declarations that do not resolve in this install shape"
+  printf '%s\n' "$OURS"
+  exit 1
+fi
+
+# tsc can still be non-zero purely from the dependency noise above. Only
+# excuse a red exit code when every reported error was attributable to a
+# dependency's declarations. A global error, or a crash that produced no
+# classifiable diagnostics at all, means the arm verified nothing and must
+# not be reported as a pass.
+if [ "$RC" -ne 0 ]; then
+  if [ -n "$GLOBAL" ] || [ -z "$OTHERS" ]; then
+    echo "::error title=type-resolution arm failed unclassified::$LABEL: tsc exited $RC for reasons not attributable to this package or its dependencies - the arm verified nothing"
+    printf '%s\n' "$OUT" | head -n 40
+    exit 1
+  fi
+  echo "type resolution ok: $LABEL (tsc exited $RC, entirely on declarations outside this package)"
+  exit 0
+fi
+
+echo "type resolution ok: $LABEL"
diff --git a/scripts/smoke/consumer-types/sdk-server.ts b/scripts/smoke/consumer-types/sdk-server.ts
new file mode 100644
index 0000000..8fb4efe
--- /dev/null
+++ b/scripts/smoke/consumer-types/sdk-server.ts
@@ -0,0 +1,11 @@
+// Consumer-side probe for the ./sdk-server subpath.
+//
+// This arm runs WITH the optional peer `@anthropic-ai/claude-agent-sdk`
+// installed, because dist/sdk-server.d.ts references a type from it and that
+// is the documented contract: the subpath exists to hand a config object to
+// the Agent SDK, so a consumer using it necessarily has the SDK (#77, option
+// (a)).
+//
+// The root arm covers the other half -- that consumers who do NOT install the
+// peer are unaffected.
+export type SdkServer = typeof import("@wave-av/mcp-server/sdk-server");
diff --git a/scripts/smoke/consumer-types/test-classifier.sh b/scripts/smoke/consumer-types/test-classifier.sh
new file mode 100755
index 0000000..84218c5
--- /dev/null
+++ b/scripts/smoke/consumer-types/test-classifier.sh
@@ -0,0 +1,84 @@
+#!/usr/bin/env bash
+# Pin the diagnostic classification in run-arm.sh.
+#
+# The bug this drill exists for: the excuse bucket used to be keyed on "the line
+# carries a file location", on the belief that tsc reports setup errors without
+# one. It does not -- `tsconfig.base.json(4,5): error TS5023` has a location --
+# so a mis-wired arm that compiled nothing was downgraded to a warning and the
+# gate exited 0 claiming "type resolution ok". Case 2 is that bug; it fails
+# against the old regex and passes against the current one.
+set -uo pipefail
+
+HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+# Mirror the two patterns under test, read straight out of run-arm.sh so this
+# drill cannot drift away from the thing it pins.
+eval "$(grep -E '^readonly (OURS_RE|DEP_DIAG_RE)=' "$HERE/run-arm.sh")"
+
+fails=0
+
+# classify <output-line> -> ours | dep | global
+classify() {
+  local line="$1"
+  if printf '%s\n' "$line" | grep -qE "$OURS_RE"; then echo ours; return; fi
+  if printf '%s\n' "$line" | grep -qE "$DEP_DIAG_RE"; then echo dep; return; fi
+  echo global
+}
+
+check() {
+  local want="$1" line="$2" why="$3" got
+  got="$(classify "$line")"
+  if [ "$got" = "$want" ]; then
+    printf 'ok    %-6s %s\n' "$got" "$why"
+  else
+    printf 'FAIL  want=%-6s got=%-6s %s\n      line: %s\n' "$want" "$got" "$why" "$line"
+    fails=$((fails + 1))
+  fi
+}
+
+# 1. Our own tarball's declarations -- always fatal.
+check ours "node_modules/@wave-av/mcp-server/dist/index.d.ts(3,1): error TS2304: Cannot find name 'Foo'." \
+  "diagnostic inside the packed tarball"
+check ours "root.ts(1,10): error TS2305: Module has no exported member 'X'." \
+  "diagnostic in a probe file"
+
+# 2. THE REGRESSION. A mis-wired tsconfig reports WITH a location and must not
+#    be excused -- this is what shipped a green gate that verified nothing.
+check global "tsconfig.base.json(4,5): error TS5023: Unknown compiler option 'totallyBogusOption'." \
+  "unknown compiler option in the arm's own tsconfig (the fail-open bug)"
+check global "tsconfig.root.json(2,3): error TS5024: Compiler option 'x' requires a value." \
+  "TS5024 against the arm's own tsconfig"
+check global "tsconfig.sdk-server.json(1,1): error TS6046: Argument for '--module' must be a string." \
+  "TS6046 against the arm's own tsconfig"
+
+# 3. Negative control -- a genuine third-party regression is still excused, so
+#    the fix tightens the gate without simply making it fail always.
+check dep "node_modules/zod/lib/types.d.ts(120,5): error TS2344: Type does not satisfy the constraint." \
+  "dependency declaration, relative path"
+# DEP_DIAG_RE's prefix group is `([^(]*/)?`, so the exact leading directories are
+# irrelevant -- what this case pins is that an ABSOLUTE prefix still classifies as
+# `dep`. The prefix is therefore composed from a variable rather than written as a
+# literal absolute home path, which the no-hardcoded-paths gate blocks on sight.
+abs_prefix="${RUNNER_TEMP:-$HOME}/work/mcp-server/arm"
+check dep "$abs_prefix/node_modules/@modelcontextprotocol/sdk/dist/x.d.ts(9,1): error TS2307: Cannot find module." \
+  "dependency declaration, absolute runner path"
+
+# 4. The bypass Corridor flagged: a directory that merely ENDS in the name is
+#    not node_modules, and must not buy an excuse.
+check global "my-node_modules/app.ts(1,1): error TS2304: Cannot find name 'Foo'." \
+  "sibling dir ending in the literal name must not be excused"
+check global "vendor/notnode_modules/pkg/index.d.ts(4,2): error TS2345: Argument type mismatch." \
+  "path segment merely containing the name must not be excused"
+
+# 5. Location-less global errors -- unchanged behaviour, still fatal.
+check global "error TS18003: No inputs were found in config file 'tsconfig.base.json'." \
+  "TS18003 with no file location"
+check global "error TS5083: Cannot read file 'tsconfig.missing.json'." \
+  "TS5083 with no file location"
+
+echo
+if [ "$fails" -ne 0 ]; then
+  echo "classifier drill: $fails case(s) FAILED"
+  exit 1
+fi
+echo "classifier drill: all cases pass"
diff --git a/scripts/smoke/consumer-types/tsconfig.base.json b/scripts/smoke/consumer-types/tsconfig.base.json
new file mode 100644
index 0000000..9bf0c05
--- /dev/null
+++ b/scripts/smoke/consumer-types/tsconfig.base.json
@@ -0,0 +1,23 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "lib": ["ES2022"],
+    "module": "nodenext",
+    "moduleResolution": "nodenext",
+    // `["node"]`, not `[]`. An empty list is not a purer test, it is a less
+    // realistic consumer: the optional peer's own declarations reference
+    // `stream`, `crypto`, `AbortSignal`, so `[]` buries the real signal under
+    // ~140 diagnostics about a dependency's need for @types/node. Anyone
+    // consuming a Node MCP server has them installed.
+    "types": ["node"],
+    "strict": true,
+    "noEmit": true,
+
+    // Deliberately FALSE. With skipLibCheck on, tsc does not look inside
+    // node_modules declarations at all -- which is exactly the class of defect
+    // this probe exists to catch (#77: dist/sdk-server.d.ts referencing an
+    // optional peer that the consumer may not have installed). Turning it on
+    // would make both arms pass unconditionally.
+    "skipLibCheck": false
+  }
+}
diff --git a/scripts/smoke/consumer-types/tsconfig.root.json b/scripts/smoke/consumer-types/tsconfig.root.json
new file mode 100644
index 0000000..a9ded94
--- /dev/null
+++ b/scripts/smoke/consumer-types/tsconfig.root.json
@@ -0,0 +1,4 @@
+{
+  "extends": "./tsconfig.base.json",
+  "files": ["root.ts"]
+}
diff --git a/scripts/smoke/consumer-types/tsconfig.sdk-server.json b/scripts/smoke/consumer-types/tsconfig.sdk-server.json
new file mode 100644
index 0000000..bb8b2d2
--- /dev/null
+++ b/scripts/smoke/consumer-types/tsconfig.sdk-server.json
@@ -0,0 +1,4 @@
+{
+  "extends": "./tsconfig.base.json",
+  "files": ["sdk-server.ts"]
+}