Add protocol-gated structured outputs to read tools - #3360
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Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 3821743d-3aec-42d3-8fa3-66ff925f1cf1
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 3821743d-3aec-42d3-8fa3-66ff925f1cf1
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 3821743d-3aec-42d3-8fa3-66ff925f1cf1
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: 3821743d-3aec-42d3-8fa3-66ff925f1cf1
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
SamMorrowDrums
marked this pull request as ready for review
October 1, 2026 22:27
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Copilot review overview
🟡 Changes recommended
Typed registration changes existing input validation, and legacy CSV calls retain an unintended JSON fallback.
Review effort: Balanced
Findings: 1
Open (2)
What changed in this PR
Adds protocol-gated structured outputs to read tools while retaining text fallbacks for older MCP clients.
Changes:
- Adds typed output registration and protocol-version gating.
- Introduces projected DTOs for read, search, security, notification, and discussion tools.
- Updates structured-output tests and tool snapshots.
| File | Description |
|---|---|
pkg/inventory/tool_availability.go |
Gates schemas and structured content by protocol. |
pkg/inventory/tool_availability_test.go |
Tests protocol gating. |
pkg/inventory/server_tool.go |
Adds typed registration and middleware support. |
pkg/inventory/server_tool_test.go |
Tests typed outputs and middleware. |
pkg/github/tools_validation_test.go |
Validates structured-output coverage. |
pkg/github/security_advisories.go |
Returns typed advisory outputs. |
pkg/github/secret_scanning.go |
Returns typed secret-alert outputs. |
pkg/github/search.go |
Adds projected code-search output. |
pkg/github/search_utils.go |
Adds typed issue/PR search results. |
pkg/github/search_test.go |
Updates code-search assertions. |
pkg/github/sanitize_coverage_test.go |
Tests projected-output sanitization. |
pkg/github/repositories.go |
Types branch and tag outputs. |
pkg/github/pullrequests.go |
Adds projected PR outputs. |
pkg/github/projected_outputs.go |
Defines projection-aware DTOs. |
pkg/github/notifications.go |
Returns typed notification outputs. |
pkg/github/notification_outputs.go |
Defines notification DTOs. |
pkg/github/notification_outputs_test.go |
Tests notification output contracts. |
pkg/github/minimal_types.go |
Adds typed projection helpers. |
pkg/github/discussions.go |
Returns typed discussion outputs. |
pkg/github/discussion_outputs.go |
Defines discussion DTOs. |
pkg/github/dependabot.go |
Returns typed Dependabot outputs. |
pkg/github/csv_output.go |
Integrates CSV as handler middleware. |
pkg/github/csv_output_test.go |
Tests CSV with structured output. |
pkg/github/context_tools.go |
Types user and team outputs. |
pkg/github/context_tools_test.go |
Tests get_me structured output. |
pkg/github/code_scanning.go |
Returns typed code-scanning outputs. |
pkg/github/code_quality.go |
Returns typed quality findings. |
pkg/github/__toolsnaps__/search_pull_requests.snap |
Records PR-search output schema. |
pkg/github/__toolsnaps__/search_issues.snap |
Records issue-search output schema. |
pkg/github/__toolsnaps__/search_code.snap |
Records code-search output schema. |
pkg/github/__toolsnaps__/list_tags.snap |
Records tag-list output schema. |
pkg/github/__toolsnaps__/list_secret_scanning_alerts.snap |
Records secret-alert list schema. |
pkg/github/__toolsnaps__/list_repository_security_advisories.snap |
Records repository-advisory schema. |
pkg/github/__toolsnaps__/list_pull_requests.snap |
Records PR-list output schema. |
pkg/github/__toolsnaps__/list_org_repository_security_advisories.snap |
Records organization-advisory schema. |
pkg/github/__toolsnaps__/list_notifications.snap |
Records notification-list schema. |
pkg/github/__toolsnaps__/list_issues.snap |
Records issue-list output schema. |
pkg/github/__toolsnaps__/list_discussions.snap |
Records discussion-list schema. |
pkg/github/__toolsnaps__/list_discussion_categories.snap |
Records category-list schema. |
pkg/github/__toolsnaps__/list_dependabot_alerts.snap |
Records Dependabot-list schema. |
pkg/github/__toolsnaps__/list_code_scanning_alerts.snap |
Records code-alert list schema. |
pkg/github/__toolsnaps__/list_branches.snap |
Records branch-list output schema. |
pkg/github/__toolsnaps__/get_teams.snap |
Records team output schema. |
pkg/github/__toolsnaps__/get_team_members.snap |
Records member output schema. |
pkg/github/__toolsnaps__/get_secret_scanning_alert.snap |
Records secret-alert schema. |
pkg/github/__toolsnaps__/get_notification_details.snap |
Records notification-detail schema. |
pkg/github/__toolsnaps__/get_me.snap |
Records current-user schema. |
pkg/github/__toolsnaps__/get_discussion.snap |
Records discussion-detail schema. |
pkg/github/__toolsnaps__/get_discussion_comments.snap |
Records discussion-comment schema. |
pkg/github/__toolsnaps__/get_dependabot_alert.snap |
Records Dependabot-alert schema. |
pkg/github/__toolsnaps__/get_code_scanning_alert.snap |
Records code-alert schema. |
pkg/github/__toolsnaps__/get_code_quality_finding.snap |
Records quality-finding schema. |
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Comment on lines
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| typedRegisterFunc = func(s *mcp.Server, tool *mcp.Tool, middleware ...ToolHandlerMiddleware) { | ||
| mcp.AddTool(s, tool, toTypedHandler(handler, middleware...)) | ||
| } |
Comment on lines
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| if callResult, ok := result.(*mcp.CallToolResult); ok && callResult.StructuredContent != nil { | ||
| resultCopy := *callResult | ||
| resultCopy.StructuredContent = nil | ||
| return &resultCopy, nil |
SamMorrowDrums
marked this pull request as draft
October 2, 2026 08:29
This was referenced Oct 2, 2026
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Summary
Adds typed output schemas and structured results to read tools, exposing them only to MCP clients negotiated on protocol
2026-07-28or later. Older and unknown-version clients keep the tools and text results, without outputSchema or structuredContent.Why
Modern MCP clients use output schemas for programmatic tool calling / Code Mode. Protocol
2025-11-25required output schema roots to be objects, while SEP-2106 in2026-07-28allows the nullable/union roots emitted by Go-inferred schemas; gating avoids advertising incompatible schemas to older clients.Fixes: N/A
What changed
2026-07-28or unknown protocol versions, preserving text content and the tool listing.MCP impact
Read tools now advertise output schemas to modern clients and return structuredContent; older clients retain text-only responses.
Prompts tested (tool changes only)
Security / limits
Existing tool scopes are preserved.
Structured output mirrors existing tool responses and does not widen authorization; projected search output remains compact and honors field selection.
Tool renaming
deprecated_tool_aliases.goNote: if you're renaming tools, you must add the tool aliases. For more information on how to do so, please refer to the official docs.
Lint & tests
./script/lint— attempted, but the repository-pinned golangci-lint v2.9.0 cannot decode Go 1.27.1 export data (internal/goarch, export data version 4; max supported version 2). Compatible golangci-lint v2.14.0 change-only check passed:/tmp/golangci-lint/golangci-lint run --new-from-rev=origin/main(0 issues)../script/test— passed (go test -race ./...). Also passedUPDATE_TOOLSNAPS=true go test ./....Docs
Ran
script/generate-docs; it produced no documentation diff.