improve pr approach

agents/shared.ts

@@ -5,4 +5,6 @@ export const instructions = `- use the ${mcpServerName} MCP server to interact w
 - do not under any circumstances use the gh cli
 - if prompted by a comment to respond to create a new issue, pr or anything else, after succeeding,
     also respond to the original comment with a very brief message containing a link to it
+- if prompted for to review a pr, use the diff_hint returned by mcp__${mcpServerName}__get_pull_request to get the diff
+    and analyze the diff to determine the review type and body
 `;

fixtures/basic.txt

@@ -1 +1 @@
-add a github review for the following PR: https://github.com/pullfrogai/scratch/pull/14
+add a github review for the following PR: https://github.com/pullfrogai/scratch/pull/16

mcp/prInfo.ts

@@ -7,7 +7,7 @@ export const PullRequestInfo = type({
 
 export const PullRequestInfoTool = tool({
   name: "get_pull_request",
-  description: "Retrieve detailed information and diff for a specific pull request by number.",
+  description: "Retrieve detailed information for a specific pull request by number, with a suggested local diff command.",
   parameters: PullRequestInfo,
   execute: contextualize(async ({ pull_number }, ctx) => {
     const pr = await ctx.octokit.rest.pulls.get({
@@ -16,19 +16,40 @@ export const PullRequestInfoTool = tool({
       pull_number,
     });
 
-    // Fetch diff using raw request
-    const diff = await ctx.octokit.request('GET /repos/{owner}/{repo}/pulls/{pull_number}', {
-      owner: ctx.owner,
-      repo: ctx.name,
-      pull_number,
-      headers: {
-        Accept: 'application/vnd.github.v3.diff',
-      },
-    });
+    const data = pr.data;
+
+    const baseBranch = data.base?.ref;
+    const headBranch = data.head?.ref;
+    const headSha = data.head?.sha;
+
+    // Suggest a local diff command similar to claude-code-action
+    // Consumers can run this in a repo checkout to view the diff without API diff access
+    const diff_hint = baseBranch
+      ? `git fetch origin ${baseBranch} --depth=20 && git diff origin/${baseBranch}...${headSha || "HEAD"}`
+      : undefined;
 
     return {
-      ...pr.data,
-      diff: diff.data,
+      number: data.number,
+      url: data.html_url,
+      title: data.title,
+      state: data.state,
+      draft: data.draft,
+      merged: data.merged,
+      mergeable: data.mergeable,
+      user: data.user?.login,
+      created_at: data.created_at,
+      updated_at: data.updated_at,
+      head: headBranch,
+      head_sha: headSha,
+      base: baseBranch,
+      base_sha: data.base?.sha,
+      additions: data.additions,
+      deletions: data.deletions,
+      changed_files: data.changed_files,
+      labels: (data.labels || []).map((l) => (typeof l === "string" ? l : l.name)).filter(Boolean),
+      requested_reviewers: (data.requested_reviewers || []).map((u) => u.login),
+      requested_teams: (data.requested_teams || []).map((t) => t.slug),
+      diff_hint,
     };
   }),
 });