Skip to content

feat(web): expose get_diff on MCP server#1142

Merged
msukkari merged 3 commits intomainfrom
michael/expose-mcp-get-diff-sou-968
Apr 21, 2026
Merged

feat(web): expose get_diff on MCP server#1142
msukkari merged 3 commits intomainfrom
michael/expose-mcp-get-diff-sou-968

Conversation

@msukkari
Copy link
Copy Markdown
Contributor

@msukkari msukkari commented Apr 21, 2026

Fixes SOU-968

Summary

  • add a new get_diff MCP tool that returns structured git diff data between base and head
  • register get_diff in the Sourcebot MCP server toolset
  • document get_diff in MCP docs with parameters aligned to the public API diff schema

Test plan

  • run yarn workspace @sourcebot/web lint
  • verify MCP descriptor includes get_diff with repo, base, head
  • call MCP get_diff for main~1..main and verify non-empty diff output
  • compare MCP get_diff output for HEAD~5..HEAD with git diff file set and stats

Made with Cursor

Summary by CodeRabbit

  • New Features
    • Added a new MCP tool, "get_diff", to return structured git diffs between two refs (repo, base, head), including changed files, hunks, line ranges, and patch content.
  • UI
    • Chat now displays a compact "Compared base to head in repo" summary with changed-file counts and a dedicated tool output renderer.
  • Documentation
    • Added user docs and changelog entry describing the new get_diff tool.

Add a new get_diff MCP tool backed by the existing git diff API so agents can request structured diffs between refs. Document the tool in MCP docs with parameters aligned to the public API spec.

Made-with: Cursor
@mintlify
Copy link
Copy Markdown

mintlify Bot commented Apr 21, 2026

Preview deployment for your docs. Learn more about Mintlify Previews.

Project Status Preview Updated (UTC)
sourcebot 🟢 Ready View Preview Apr 21, 2026, 5:24 PM

💡 Tip: Enable Workflows to automatically generate PRs for you.

@github-actions

This comment has been minimized.

@coderabbitai
Copy link
Copy Markdown
Contributor

coderabbitai Bot commented Apr 21, 2026

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info
⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 278f62cc-74d6-4442-bb7a-414d44b0eee3

📥 Commits

Reviewing files that changed from the base of the PR and between f401c24 and a7511d7.

📒 Files selected for processing (4)
  • packages/web/src/features/chat/agent.ts
  • packages/web/src/features/chat/components/chatThread/detailsCard.tsx
  • packages/web/src/features/chat/components/chatThread/tools/getDiffToolComponent.tsx
  • packages/web/src/features/chat/tools.ts

Walkthrough

Adds a new MCP tool get_diff that returns a structured git diff between two refs; includes tool implementation, schema, MCP registration, UI rendering, docs, and changelog entry. (50 words)

Changes

Cohort / File(s) Summary
Documentation
docs/docs/features/mcp-server.mdx, packages/web/src/features/tools/getDiff.txt
Added documentation for the get_diff tool, describing purpose and required parameters: repo, base, head.
Tool Implementation
packages/web/src/features/tools/getDiff.ts
New tool definition getDiffDefinition with request schema, logging, call to getDiff, service-error handling, JSON-stringified output, and enriched metadata.
Tool Barrel & Server Registration
packages/web/src/features/tools/index.ts, packages/web/src/features/mcp/server.ts
Re-exported getDiff from tools barrel and registered get_diff with the MCP server.
Chat Integration & UI
packages/web/src/features/chat/tools.ts, packages/web/src/features/chat/components/chatThread/detailsCard.tsx, packages/web/src/features/chat/components/chatThread/tools/getDiffToolComponent.tsx, packages/web/src/features/chat/agent.ts
Added chat/tool mapping, UI part type, rendering case for tool-get_diff, new GetDiffToolComponent, and updated system prompt examples to include get_diff.
Changelog
CHANGELOG.md
Added Unreleased note recording the new get_diff MCP tool (#1142).

Sequence Diagram(s)

sequenceDiagram
    participant Client as Client
    participant MCP as MCP Server
    participant Tool as get_diff Tool
    participant DiffSvc as Diff Service

    Client->>MCP: Request get_diff(repo, base, head)
    MCP->>Tool: invoke handler with params
    Tool->>DiffSvc: getDiff(repo, base, head)
    DiffSvc-->>Tool: diff result / error
    alt success
        Tool-->>MCP: return JSON output + metadata
        MCP-->>Client: 200 + diff payload
    else service error
        Tool-->>MCP: throw Error(response.message)
        MCP-->>Client: 5xx error
    end
Loading

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

Suggested reviewers

  • brendan-kellam
🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name Status Explanation Resolution
Docstring Coverage ⚠️ Warning Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Write docstrings for the functions missing them to satisfy the coverage threshold.
✅ Passed checks (4 passed)
Check name Status Explanation
Description Check ✅ Passed Check skipped - CodeRabbit’s high-level summary is enabled.
Title check ✅ Passed The title 'feat(web): expose get_diff on MCP server' clearly and concisely summarizes the main change: adding and exposing the get_diff tool to the MCP server.
Linked Issues check ✅ Passed Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check ✅ Passed Check skipped because no linked issues were found for this pull request.

✏️ Tip: You can configure your own custom pre-merge checks in the settings.

✨ Finishing Touches
📝 Generate docstrings
  • Create stacked PR
  • Commit on current branch
🧪 Generate unit tests (beta)
  • Create PR with unit tests
  • Commit unit tests in branch michael/expose-mcp-get-diff-sou-968

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

Comment @coderabbitai help to get the list of available commands and usage tips.

Document the new MCP get_diff capability under Unreleased using the repository changelog format and PR link.

Made-with: Cursor
Copy link
Copy Markdown
Contributor

@coderabbitai coderabbitai Bot left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

🧹 Nitpick comments (1)
packages/web/src/features/tools/getDiff.ts (1)

21-39: Consider size limits for large diffs.

JSON.stringify(response) returns the full diff with no truncation or size cap. For large base..head ranges this could produce very large outputs that exceed MCP client limits or consume excessive tokens. Consider adding a max file/hunk cap or a size guard, similar to the limit parameters on other tools (grep, glob, list_commits).

🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.

In `@packages/web/src/features/tools/getDiff.ts` around lines 21 - 39, The execute
handler currently returns the full diff (JSON.stringify(response)) which can be
arbitrarily large; update the execute implementation in getDiff.ts (the execute
function that calls getDiff and uses isServiceError) to enforce a size/entry
cap: either pass a new limit parameter into getDiff (e.g., file/hunk limit) or
truncate the response before stringifying (e.g., keep first N files/hunks and
set a truncated=true flag), and include metadata that indicates truncation along
with repo/base/head; ensure you still throw on isServiceError(response) and
preserve the existing metadata merge but replace output with the
capped/truncated JSON to avoid oversized payloads.
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@packages/web/src/features/tools/getDiff.ts`:
- Around line 21-39: The execute handler currently returns the full diff
(JSON.stringify(response)) which can be arbitrarily large; update the execute
implementation in getDiff.ts (the execute function that calls getDiff and uses
isServiceError) to enforce a size/entry cap: either pass a new limit parameter
into getDiff (e.g., file/hunk limit) or truncate the response before
stringifying (e.g., keep first N files/hunks and set a truncated=true flag), and
include metadata that indicates truncation along with repo/base/head; ensure you
still throw on isServiceError(response) and preserve the existing metadata merge
but replace output with the capped/truncated JSON to avoid oversized payloads.

ℹ️ Review info
⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 53057228-4605-4cf8-8dea-8558c9bc0381

📥 Commits

Reviewing files that changed from the base of the PR and between 48ad44d and a23c35a.

📒 Files selected for processing (5)
  • docs/docs/features/mcp-server.mdx
  • packages/web/src/features/mcp/server.ts
  • packages/web/src/features/tools/getDiff.ts
  • packages/web/src/features/tools/getDiff.txt
  • packages/web/src/features/tools/index.ts

brendan-kellam
brendan-kellam previously approved these changes Apr 21, 2026
Register get_diff in the Ask agent toolset and render its output in the details panel so chat workflows can compare refs directly.

Made-with: Cursor
@msukkari msukkari merged commit 14ca65d into main Apr 21, 2026
6 of 7 checks passed
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

2 participants