[guard-coverage] Guard coverage gap: 2 operations from github-mcp-server / GitHub CLI not fully covered

[github-actions]

Summary

The GitHub guard does not fully cover 2 operation(s) from the github-mcp-server source inventory.

• MCP tools scanned: 115 source-registered tools
• CLI write commands scanned: 79
• Guard-covered write tools (tools.rs): 116 (WRITE_OPERATIONS + READ_WRITE_OPERATIONS)
• Tools with explicit DIFC rules (tool_rules.rs): 113 of 115 upstream tools
• New gaps found this run: 2

No new CLI-only gaps were identified in the scoped GitHub CLI write-command set. The newly observed gap is a feature-flagged upstream MCP capability for issue dependency relationships.

---

MCP Tool Classification Gaps (tools.rs)

These MCP tools perform write or mutating operations but are missing from WRITE_OPERATIONS or READ_WRITE_OPERATIONS in guards/github-guard/rust-guard/src/tools.rs:

Tool Name	Operation Type	Suggested Classification	Notes
issue_dependency_write	read-write	READ_WRITE_OPERATIONS	Adds/removes blocked-by and blocking relationships between issues after resolving issue numbers to GraphQL node IDs

Suggested fix for tools.rs

pub const READ_WRITE_OPERATIONS: &[&str] = &[
    // ... existing entries ...
    "issue_dependency_write", // GraphQL addBlockedBy/removeBlockedBy after resolving issue IDs
    // ... existing entries ...
];

---

MCP Tool DIFC Labeling Gaps (tool_rules.rs)

These upstream tools have no explicit match arm in apply_tool_labels and currently fall through to default label handling:

Tool Name	Data Scope	Suggested Labels	Risk
issue_dependency_read	repo-scoped issue graph	secrecy: S(repo), integrity: same baseline as issue_read / repo-private reader floor	Medium
issue_dependency_write	repo-scoped issue graph mutation	secrecy: S(repo), integrity: writer(repo)	High

Suggested fix for tool_rules.rs

Add explicit handling alongside the issue rules:

"issue_dependency_read" => {
    secrecy = apply_repo_visibility_secrecy(&owner, &repo, repo_id, secrecy, ctx);
    integrity = private_writer_integrity(repo_id, repo_private, ctx);
}

"issue_dependency_write" => {
    if !owner.is_empty() && !repo.is_empty() {
        if let Some(issue_num) = extract_number_as_string(tool_args, field_names::ISSUE_NUMBER) {
            desc = format!("issue:{}/{}#{}", owner, repo, issue_num);
        }
    }
    secrecy = apply_repo_visibility_secrecy(&owner, &repo, repo_id, secrecy, ctx);
    integrity = writer_integrity(repo_id, ctx);
}

If you want issue_dependency_read to inherit author-derived integrity exactly like issue_read, factor the shared issue-scoped read logic into a helper and reuse it for both tools.

---

GitHub CLI-Only Gaps

No new CLI-only guard gaps were identified in this run.

---

References

• github-mcp-server tools
• github-mcp-server source inventory
• guard tools.rs
• guard tool_rules.rs
• Run: §28277052550

Generated by GitHub Guard Coverage Checker (MCP + CLI) · 646.9 AIC · ⊞ 30.7K · ◷

• expires on Jul 11, 2026, 3:25 AM UTC

[github-actions]

🤖 This is an automated response from Repo Assist.

I've verified both gaps reported here against the current codebase.

Gap 1: issue_dependency_write missing from READ_WRITE_OPERATIONS

Confirmed. tools.rs has no entry for issue_dependency_write. Alphabetically it belongs after delete_pending_pull_request_review and before issue_write (current line 102):

"delete_pending_pull_request_review", // DELETE /repos/.../pulls/{number}/reviews/{id}
"issue_dependency_write",             // GraphQL addBlockedBy/removeBlockedBy after resolving issue IDs
"issue_write",

Gap 2: No explicit DIFC rules for either tool

Confirmed. Neither issue_dependency_read nor issue_dependency_write appears anywhere in labels/tool_rules.rs. Both fall through to the default handler.

For issue_dependency_read, the cleanest fix is to extend the existing issues read arm (line 142) since it shares the same secrecy profile (S(repo), I = private_writer_integrity) and no individual issue number is needed:

"get_issue" | "issue_read" | "list_issues" | "list_issues_ff_remote_mcp_issue_fields"
| "issue_dependency_read" => {

For issue_dependency_write, it belongs in the large repo-scoped write block alongside sub_issue_write/add_sub_issue/remove_sub_issue, which cover similar issue-graph mutation.

Happy to put up a PR with these three changes plus tests if that would be helpful.

Generated by Repo Assist · 135.8 AIC · ⊞ 12.2K · ◷
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