fix: reviews failing to call next tool

mcp/checkout.ts

@@ -487,9 +487,9 @@ export function CheckoutPrTool(ctx: ToolContext) {
       hookWarning: checkoutResult.hookWarning,
       instructions:
         `the diff file at diffPath contains a table of contents (TOC) listing every changed file with its line range. ` +
-        `use the TOC line ranges as your checklist and read specific files from the diff. ` +
-        `for example, if the TOC says "src/foo.ts → lines 5-42", read lines 5-42 from diffPath. ` +
-        `review files selectively based on relevance. ` +
+        `to read the diff, use the shell MCP tool — for example: shell({ command: 'sed -n "<start>,<end>p" ${join(tempDir, `pr-${pull_number}-${headShort}.diff`)}', description: 'read diff section' }). ` +
+        `use the TOC line ranges as your checklist and read specific sections. ` +
+        `for example, if the TOC says "src/foo.ts → lines 5-42", run: shell({ command: 'sed -n "5,42p" <diffPath>', description: 'read foo.ts diff' }). ` +
         `IMPORTANT: to inspect the PR's changed files, read diffPath directly — ` +
         `do NOT run git diff or git show. The PR base branch is '${pr.baseRef}', NOT necessarily 'main' — ` +
         `if you must use git, use 'origin/${pr.baseRef}' as the base (e.g. git log origin/${pr.baseRef}..HEAD), ` +