diff --git a/.mcp-sdk.lock b/.mcp-sdk.lock
index 44c9e08..7d62f71 100644
--- a/.mcp-sdk.lock
+++ b/.mcp-sdk.lock
@@ -1,2 +1,2 @@
-version=v1.0.0
-sha256=8f683045f3ae724ce781fa40bcfe97bf2ee74f1b44aaf38afef38854e365ee90
+version=v2.0.0
+sha256=4b63025f6d9328436a8c0fd69e3e53c3205de642d0223481459ab9767f2309cd
diff --git a/plugin-tests/github-mcp/tool_schemas.bats b/plugin-tests/github-mcp/tool_schemas.bats
index d53a6fc..8f8b990 100644
--- a/plugin-tests/github-mcp/tool_schemas.bats
+++ b/plugin-tests/github-mcp/tool_schemas.bats
@@ -71,11 +71,14 @@ load_validator_for() {
         | select($prop.default != null)
         | select(
             ($prop.enum != null and ($prop.enum | index($prop.default)) == null)
-            or (($prop.type | type) == "string" and (
-                if $prop.type == "integer"
-                then ($prop.default | type) != "number"
-                else ($prop.default | type) != $prop.type
-                end))
+            or ($prop.type != null and (
+                (if ($prop.type | type) == "array" then $prop.type else [$prop.type] end) as $names
+                | all($names[]; type == "string")
+                  and (any($names[];
+                        if . == "integer"
+                        then ($prop.default | type) == "number"
+                        else ($prop.default | type) == .
+                        end) | not)))
           )
         | "\($tool).\($field) default \($prop.default | tojson) violates its own schema"' \
         "$READ_TOOLS" "$WRITE_TOOLS"
diff --git a/plugins/github-mcp/AGENTS.md b/plugins/github-mcp/AGENTS.md
index 811813f..429aa69 100644
--- a/plugins/github-mcp/AGENTS.md
+++ b/plugins/github-mcp/AGENTS.md
@@ -198,5 +198,5 @@ Run tests:
 
 ## External References
 
-- [Bash MCP SDK](https://github.com/muthuishere/mcp-server-bash-sdk) - SDK this server is based on
+- [Bash MCP SDK](https://github.com/shopwareLabs/bash-mcp-sdk) - source of the vendored `shared/mcpserver_core.sh`; pinned in `.mcp-sdk.lock`
 - [MCP Protocol Specification](https://modelcontextprotocol.io/specification) - JSON-RPC 2.0 protocol details
diff --git a/plugins/github-mcp/CHANGELOG.md b/plugins/github-mcp/CHANGELOG.md
index 2ee48eb..1fad637 100644
--- a/plugins/github-mcp/CHANGELOG.md
+++ b/plugins/github-mcp/CHANGELOG.md
@@ -8,8 +8,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Changed
-- `shared/mcpserver_core.sh` is now vendored from [shopwareLabs/bash-mcp-sdk](https://github.com/shopwareLabs/bash-mcp-sdk) `v1.0.0` instead of being maintained in this repository. The file is byte-identical to `lib/mcpserver_core.sh` at that tag; `.mcp-sdk.lock` records the release and `renovate.json` opens a PR when a new one is published. Protocol changes now go to the SDK repository and arrive here as a lock bump — a local edit is overwritten by the next update.
-- Tool-call argument validation now enforces a declared `type`, a declared `pattern` on string values, `items.type` / `items.enum` on every element of an array, and `enum`. The `required` and `additionalProperties` checks were already applied. Diagnostics report the most fundamental defect first, in the order missing, unknown, type, pattern, items, enum. **Breaking for callers:** an argument of the wrong single type that was previously accepted and passed through to `gh` now returns an `isError` result naming the parameter, its expected type and the value received. This affects the integer-typed paging and output parameters — `limit`, `max_lines`, `tail_lines`, `grep_context_before`, `grep_context_after`, `line_start`, `line_end` — where a quoted number such as `"20"` is now refused. Identifier parameters declare `["integer", "string"]`; the pinned SDK `v1.0.0` does not enforce array-valued types, so it does not validate that their values belong to either member.
+- `shared/mcpserver_core.sh` is now vendored from [shopwareLabs/bash-mcp-sdk](https://github.com/shopwareLabs/bash-mcp-sdk) `v2.0.0` instead of being maintained in this repository. The file is byte-identical to `lib/mcpserver_core.sh` at that tag; `.mcp-sdk.lock` records the release and `renovate.json` opens a PR when a new one is published. Protocol changes now go to the SDK repository and arrive here as a lock bump — a local edit is overwritten by the next update.
+- Tool-call argument validation now enforces a declared `type`, a declared `pattern` on string values, `items.type` / `items.enum` on every element of an array, and `enum`. The `required` and `additionalProperties` checks were already applied. Diagnostics report the most fundamental defect first, in the order missing, unknown, type, pattern, items, enum. **Breaking for callers:** an argument of the wrong single type that was previously accepted and passed through to `gh` now returns an `isError` result naming the parameter, its expected type and the value received. This affects the integer-typed paging and output parameters — `limit`, `max_lines`, `tail_lines`, `grep_context_before`, `grep_context_after`, `line_start`, `line_end` — where a quoted number such as `"20"` is now refused. A `type` declared as a list of alternatives is enforced the same way: identifier parameters declare `["integer", "string"]` and accept `339` and `"339"` alike, while a value of neither type is refused naming both — `number expected integer or string, got boolean`.
 - `project_view.number`, and `issue_number` / `sub_issue_number` on `sub_issue_add` and `sub_issue_remove`, now declare `["integer", "string"]`. They were the only numeric identifiers still declared integer-only, so the string form a client may send would have been refused by the stricter validation above. The tool functions read both forms through `jq -r`; `sub_issue_add` and `sub_issue_remove` check the result with `_gh_validate_number`, while `project_view` checks that it is non-empty. Only the schemas were narrower.
 
 ### Fixed
diff --git a/plugins/github-mcp/shared/mcpserver_core.sh b/plugins/github-mcp/shared/mcpserver_core.sh
index e2a4742..913965a 100755
--- a/plugins/github-mcp/shared/mcpserver_core.sh
+++ b/plugins/github-mcp/shared/mcpserver_core.sh
@@ -118,15 +118,19 @@ handle_tools_list() {
 # Rejects arguments that are not a JSON object, enforces `required` (every
 # listed field must be present), when the schema sets
 # `additionalProperties: false` rejects any field not in `properties`,
-# enforces a declared scalar `type` (string, integer, number, boolean, array,
+# enforces a declared `type` (string, integer, number, boolean, array,
 # object) on any present field, enforces a declared `pattern` against any
 # present string-valued field, enforces a declared array `items.type` and
 # `items.enum` against every element of a present array-valued field, and
 # rejects any present field whose schema declares an `enum` when the supplied
-# value is not one of the declared values. Diagnostics take precedence in
-# that order — missing, unknown, type, pattern, items, enum — so a value that
-# fails more than one constraint is reported with the most fundamental defect
-# first (a type mismatch is reported before an unrelated enum mismatch).
+# value is not one of the declared values. A declared `type` — on a property
+# or on `items` — is either one name or a list of alternatives, and a value
+# satisfies it by matching any member; a list that is empty or carries a
+# non-string member is malformed and left unenforced. Diagnostics take
+# precedence in that order — missing, unknown, type, pattern, items, enum — so
+# a value that fails more than one constraint is reported with the most
+# fundamental defect first (a type mismatch is reported before an unrelated
+# enum mismatch).
 # A tool with no entry in the tools list, or whose entry declares no
 # inputSchema, is not validated. A jq failure is a rejection and never a skip:
 # a validator that could not evaluate its input has not validated it, and
@@ -165,21 +169,37 @@ validate_tool_arguments() {
         --argjson schema "$schema" \
         --argjson args "$arguments" \
         '
-        # `want == "integer"` treats a whole-valued JSON number as satisfying
-        # it (JSON has no distinct integer type); every other `want` is a
-        # plain jq `type` comparison.
+        # A declared `type` is one name or a list of alternatives, so it is
+        # normalized to a list and one comparison serves both forms.
+        # `"integer"` treats a whole-valued JSON number as satisfying it (JSON
+        # has no distinct integer type); every other name is a plain jq `type`
+        # comparison.
+        def type_names(want):
+            if (want | type) == "array" then want else [want] end;
         def type_ok(want; val):
-            if want == "integer" then
-                (val | type) == "number" and (val == (val | floor))
-            else
-                (val | type) == want
-            end;
+            any(type_names(want)[];
+                if . == "integer" then
+                    (val | type) == "number" and (val == (val | floor))
+                else
+                    (val | type) == .
+                end);
+        # Only reached after `type_ok` failed, so a number here has already
+        # failed every declared alternative: with `integer` offered it is
+        # necessarily non-integer and reads "number (non-integer)". A list
+        # offering `number` accepts every number, so the `number` conjunct
+        # cannot fire at either call site — it keeps the label correct if the
+        # function is ever called somewhere `type_ok` did not gate.
         def type_label(want; val):
-            if want == "integer" and (val | type) == "number" then
+            (type_names(want)) as $w
+            | if (val | type) == "number"
+                 and ($w | index("integer")) != null
+                 and ($w | index("number")) == null then
                 "number (non-integer)"
-            else
+              else
                 (val | type)
-            end;
+              end;
+        def type_expected(want):
+            type_names(want) | join(" or ");
         if ($args | type) != "object" then
             "Invalid arguments: expected a JSON object, got "
             + ($args | type) + "."
@@ -194,10 +214,14 @@ validate_tool_arguments() {
             else [] end )                        as $unknown
         | [ $present[] | . as $p
             | ($props[$p].type // empty)          as $t
-            | select($t != null and ($t | type) == "string")
+            | select($t != null)
+            | (type_names($t))                     as $tn
+            # A malformed `type` — an empty list, or one carrying a non-string
+            # member — is left unenforced rather than rejecting every value.
+            | select(($tn | length) > 0 and all($tn[]; type == "string"))
             | ($args[$p])                          as $v
             | select((type_ok($t; $v)) | not)
-            | {p: $p, expected: $t, actual: type_label($t; $v), v: $v}
+            | {p: $p, expected: type_expected($t), actual: type_label($t; $v), v: $v}
           ]                                      as $invalid_type
         | [ $present[] | . as $p
             | ($props[$p].pattern // empty)       as $pat
@@ -226,8 +250,11 @@ validate_tool_arguments() {
                 | . as $entry
                 | ($entry.value)                    as $ev
                 | ($entry.key)                       as $idx
-                | if ($it != null and ($it | type) == "string" and (type_ok($it; $ev) | not)) then
-                    {p: $p, index: $idx, issue: "type", expected: $it, actual: type_label($it; $ev), v: $ev}
+                | if ($it != null
+                      and ((type_names($it)) as $itn
+                           | ($itn | length) > 0 and all($itn[]; type == "string"))
+                      and (type_ok($it; $ev) | not)) then
+                    {p: $p, index: $idx, issue: "type", expected: type_expected($it), actual: type_label($it; $ev), v: $ev}
                   elif ($ie != null and ($ie | index($ev)) == null) then
                     {p: $p, index: $idx, issue: "enum", enum: $ie, v: $ev}
                   else empty end