Add issue dependency read/write MCP tools

Add two feature-flagged tools for issue blocked-by / blocking
relationships, gated behind the issue_dependencies flag so they stay off
the default tool surface (auto-enabled for insiders only):

- issue_dependency_read: get_blocked_by / get_blocking via the
  Issue.blockedBy / Issue.blocking GraphQL connections, cursor-paginated.
- issue_dependency_write: add / remove x blocked_by / blocking via the
  addBlockedBy / removeBlockedBy mutations. Accepts issue numbers and
  resolves them to node IDs in a single aliased query; "blocking" is the
  inverse of "blocked_by" with the subject/related roles swapped.

Closes the MCP gap behind the gh CLI dependency verbs (cli/cli#13057).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: zwick

docs/feature-flags.md

@@ -75,7 +75,7 @@ runtime behavior (such as output formatting) won't appear here.
   - `type`: Type of this issue. Only use if issue types are enabled for this repository. Use list_issue_types tool to get valid type values for this repository or its owner organization. If the repository doesn't support issue types, omit this parameter. (string, optional)
 
 - **ui_get** - Get UI data
-  - **Required OAuth Scopes**: `repo`, `read:org`
+  - **Required OAuth Scopes (any of)**: `repo`, `read:org`
   - **Accepted OAuth Scopes**: `admin:org`, `read:org`, `repo`, `write:org`
   - `method`: The type of data to fetch (string, required)
   - `owner`: Repository owner (required for all methods) (string, required)
@@ -324,4 +324,36 @@ runtime behavior (such as output formatting) won't appear here.
   - `repo`: Repository name (string, required)
   - `start_line`: Optional 1-based starting line of the window of interest. Only ranges overlapping [start_line, end_line] are returned, clamped to the window. (number, optional)
 
+### `issue_dependencies`
+
+- **issue_dependency_read** - Read issue dependencies
+  - **Required OAuth Scopes**: `repo`
+  - `after`: Cursor for pagination. Use the cursor from the previous response. (string, optional)
+  - `issue_number`: The number of the issue (number, required)
+  - `method`: The read operation to perform on a single issue's dependencies.
+    Options are:
+    1. get_blocked_by - List the issues that block this issue (this issue is blocked by them).
+    2. get_blocking - List the issues that this issue blocks.
+     (string, required)
+  - `owner`: The owner of the repository (string, required)
+  - `perPage`: Results per page for pagination (min 1, max 100) (number, optional)
+  - `repo`: The name of the repository (string, required)
+
+- **issue_dependency_write** - Change issue dependency
+  - **Required OAuth Scopes**: `repo`
+  - `issue_number`: The number of the subject issue (number, required)
+  - `method`: The action to perform.
+    Options are:
+    - 'add' - create the dependency relationship.
+    - 'remove' - delete the dependency relationship. (string, required)
+  - `owner`: The owner of the subject issue's repository (string, required)
+  - `related_issue_number`: The number of the related issue to link or unlink (number, required)
+  - `related_owner`: The owner of the related issue's repository. Defaults to 'owner' when omitted. (string, optional)
+  - `related_repo`: The name of the related issue's repository. Defaults to 'repo' when omitted. (string, optional)
+  - `repo`: The name of the subject issue's repository (string, required)
+  - `type`: The relationship direction relative to the subject issue.
+    Options are:
+    - 'blocked_by' - the subject issue is blocked by the related issue.
+    - 'blocking' - the subject issue blocks the related issue. (string, required)
+
 <!-- END AUTOMATED FEATURE FLAG TOOLS -->

docs/insiders-features.md

@@ -69,7 +69,7 @@ The list below is generated from the Go source. It covers tool **inventory and s
   - `type`: Type of this issue. Only use if issue types are enabled for this repository. Use list_issue_types tool to get valid type values for this repository or its owner organization. If the repository doesn't support issue types, omit this parameter. (string, optional)
 
 - **ui_get** - Get UI data
-  - **Required OAuth Scopes**: `repo`, `read:org`
+  - **Required OAuth Scopes (any of)**: `repo`, `read:org`
   - **Accepted OAuth Scopes**: `admin:org`, `read:org`, `repo`, `write:org`
   - `method`: The type of data to fetch (string, required)
   - `owner`: Repository owner (required for all methods) (string, required)
@@ -144,6 +144,38 @@ The list below is generated from the Go source. It covers tool **inventory and s
   - `repo`: Repository name (string, required)
   - `start_line`: Optional 1-based starting line of the window of interest. Only ranges overlapping [start_line, end_line] are returned, clamped to the window. (number, optional)
 
+### `issue_dependencies`
+
+- **issue_dependency_read** - Read issue dependencies
+  - **Required OAuth Scopes**: `repo`
+  - `after`: Cursor for pagination. Use the cursor from the previous response. (string, optional)
+  - `issue_number`: The number of the issue (number, required)
+  - `method`: The read operation to perform on a single issue's dependencies.
+    Options are:
+    1. get_blocked_by - List the issues that block this issue (this issue is blocked by them).
+    2. get_blocking - List the issues that this issue blocks.
+     (string, required)
+  - `owner`: The owner of the repository (string, required)
+  - `perPage`: Results per page for pagination (min 1, max 100) (number, optional)
+  - `repo`: The name of the repository (string, required)
+
+- **issue_dependency_write** - Change issue dependency
+  - **Required OAuth Scopes**: `repo`
+  - `issue_number`: The number of the subject issue (number, required)
+  - `method`: The action to perform.
+    Options are:
+    - 'add' - create the dependency relationship.
+    - 'remove' - delete the dependency relationship. (string, required)
+  - `owner`: The owner of the subject issue's repository (string, required)
+  - `related_issue_number`: The number of the related issue to link or unlink (number, required)
+  - `related_owner`: The owner of the related issue's repository. Defaults to 'owner' when omitted. (string, optional)
+  - `related_repo`: The name of the related issue's repository. Defaults to 'repo' when omitted. (string, optional)
+  - `repo`: The name of the subject issue's repository (string, required)
+  - `type`: The relationship direction relative to the subject issue.
+    Options are:
+    - 'blocked_by' - the subject issue is blocked by the related issue.
+    - 'blocking' - the subject issue blocks the related issue. (string, required)
+
 <!-- END AUTOMATED INSIDERS TOOLS -->
 
 ---

pkg/github/__toolsnaps__/issue_dependency_read_ff_issue_dependencies.snap

@@ -0,0 +1,49 @@
+{
+  "annotations": {
+    "readOnlyHint": true,
+    "title": "Read issue dependencies"
+  },
+  "description": "Read an issue's dependency relationships in a GitHub repository: the issues that block it (blocked_by) or the issues it blocks (blocking).",
+  "inputSchema": {
+    "properties": {
+      "after": {
+        "description": "Cursor for pagination. Use the cursor from the previous response.",
+        "type": "string"
+      },
+      "issue_number": {
+        "description": "The number of the issue",
+        "type": "number"
+      },
+      "method": {
+        "description": "The read operation to perform on a single issue's dependencies.\nOptions are:\n1. get_blocked_by - List the issues that block this issue (this issue is blocked by them).\n2. get_blocking - List the issues that this issue blocks.\n",
+        "enum": [
+          "get_blocked_by",
+          "get_blocking"
+        ],
+        "type": "string"
+      },
+      "owner": {
+        "description": "The owner of the repository",
+        "type": "string"
+      },
+      "perPage": {
+        "description": "Results per page for pagination (min 1, max 100)",
+        "maximum": 100,
+        "minimum": 1,
+        "type": "number"
+      },
+      "repo": {
+        "description": "The name of the repository",
+        "type": "string"
+      }
+    },
+    "required": [
+      "method",
+      "owner",
+      "repo",
+      "issue_number"
+    ],
+    "type": "object"
+  },
+  "name": "issue_dependency_read"
+}

pkg/github/__toolsnaps__/issue_dependency_write_ff_issue_dependencies.snap

@@ -0,0 +1,60 @@
+{
+  "annotations": {
+    "title": "Change issue dependency"
+  },
+  "description": "Add or remove an issue dependency relationship in a GitHub repository. Use type 'blocked_by' to record that the subject issue is blocked by a related issue, or type 'blocking' to record that the subject issue blocks a related issue. The related issue defaults to the same repository as the subject unless related_owner/related_repo are provided.",
+  "inputSchema": {
+    "properties": {
+      "issue_number": {
+        "description": "The number of the subject issue",
+        "type": "number"
+      },
+      "method": {
+        "description": "The action to perform.\nOptions are:\n- 'add' - create the dependency relationship.\n- 'remove' - delete the dependency relationship.",
+        "enum": [
+          "add",
+          "remove"
+        ],
+        "type": "string"
+      },
+      "owner": {
+        "description": "The owner of the subject issue's repository",
+        "type": "string"
+      },
+      "related_issue_number": {
+        "description": "The number of the related issue to link or unlink",
+        "type": "number"
+      },
+      "related_owner": {
+        "description": "The owner of the related issue's repository. Defaults to 'owner' when omitted.",
+        "type": "string"
+      },
+      "related_repo": {
+        "description": "The name of the related issue's repository. Defaults to 'repo' when omitted.",
+        "type": "string"
+      },
+      "repo": {
+        "description": "The name of the subject issue's repository",
+        "type": "string"
+      },
+      "type": {
+        "description": "The relationship direction relative to the subject issue.\nOptions are:\n- 'blocked_by' - the subject issue is blocked by the related issue.\n- 'blocking' - the subject issue blocks the related issue.",
+        "enum": [
+          "blocked_by",
+          "blocking"
+        ],
+        "type": "string"
+      }
+    },
+    "required": [
+      "method",
+      "type",
+      "owner",
+      "repo",
+      "issue_number",
+      "related_issue_number"
+    ],
+    "type": "object"
+  },
+  "name": "issue_dependency_write"
+}

pkg/github/feature_flags.go

@@ -21,6 +21,13 @@ const FeatureFlagIssueFields = "remote_mcp_issue_fields"
 // is not advertised by default, keeping the tool surface small unless opted in.
 const FeatureFlagFileBlame = "file_blame"
 
+// FeatureFlagIssueDependencies is the feature flag name for the issue dependency
+// tools (issue_dependency_read / issue_dependency_write), which read and edit an
+// issue's blocked-by / blocking relationships. It is gated so these tools are not
+// advertised in the default surface, keeping the fixed tool-schema cost small
+// unless explicitly opted in.
+const FeatureFlagIssueDependencies = "issue_dependencies"
+
 // AllowedFeatureFlags is the allowlist of feature flags that can be enabled
 // by users via --features CLI flag or X-MCP-Features HTTP header.
 // Only flags in this list are accepted; unknown flags are silently ignored.
@@ -33,6 +40,7 @@ var AllowedFeatureFlags = []string{
 	FeatureFlagIssuesGranular,
 	FeatureFlagPullRequestsGranular,
 	FeatureFlagFileBlame,
+	FeatureFlagIssueDependencies,
 }
 
 // InsidersFeatureFlags is the list of feature flags that insiders mode enables.
@@ -44,6 +52,7 @@ var InsidersFeatureFlags = []string{
 	FeatureFlagCSVOutput,
 	FeatureFlagIssueFields,
 	FeatureFlagFileBlame,
+	FeatureFlagIssueDependencies,
 }
 
 // FeatureFlags defines runtime feature toggles that adjust tool behavior.