fix(github): accepted case-only run url repo matches

resolveGitHubRepo rejected calls that supplied both an explicit repo and a full Actions run URL when the two owner/repo slugs differed only by casing. GitHub repository paths are case-insensitive, so this was the same class of false mismatch as the cwd guard fixed earlier.

Compare repo slugs through a shared ASCII case-insensitive helper and use it for both the run-URL consistency check and the cwd guard. Added a regression test for repo=cagedbird043/cxf with a run URL under CagedBird043/CXF.

Refs #1949 #1951

packages/coding-agent/src/tools/gh.ts

@@ -792,6 +792,19 @@ function repoFromRepositoryUrl(value: string | undefined): string | undefined {
 	return value.slice(REPO_API_URL_PREFIX.length);
 }
 
+function githubRepoSlugEquals(left: string | undefined, right: string): boolean {
+	if (left === undefined || left.length !== right.length) return false;
+	for (let idx = 0; idx < left.length; idx += 1) {
+		let leftCode = left.charCodeAt(idx);
+		let rightCode = right.charCodeAt(idx);
+		if (leftCode >= 65 && leftCode <= 90) leftCode += 32;
+		if (rightCode >= 65 && rightCode <= 90) rightCode += 32;
+		if (leftCode !== rightCode) return false;
+	}
+	return true;
+}
+
+
 function apiUserToGhUser(user: GhApiUser | null | undefined): GhUser | undefined {
 	if (!user) return undefined;
 	const login = user.login ?? undefined;
@@ -1646,7 +1659,7 @@ async function resolveGitHubRepo(
 	runRepo: string | undefined,
 	signal?: AbortSignal,
 ): Promise<string> {
-	if (repo && runRepo && repo !== runRepo) {
+	if (repo && runRepo && !githubRepoSlugEquals(repo, runRepo)) {
 		throw new ToolError("run URL repository does not match the provided repo");
 	}
 
@@ -3443,7 +3456,7 @@ async function executeRunWatch(
 		// while callers may pass any casing — so the equality check normalizes
 		// both sides before deciding the cwd is a different repo (PR #1951).
 		const cwdRepo = await tryResolveCurrentRepo(session.cwd, signal);
-		if (cwdRepo?.toLowerCase() !== repo.toLowerCase()) {
+		if (!githubRepoSlugEquals(cwdRepo, repo)) {
 			throw new ToolError(
 				`Cannot infer the watched commit for ${repo}: current checkout is ${cwdRepo ?? "not a GitHub repository"}. Pass \`branch\` or \`run\` to scope the watch.`,
 			);

packages/coding-agent/test/tools/gh.test.ts

@@ -1051,6 +1051,47 @@ describe("github tool", () => {
 		expect(result.details?.repo).toBe(targetRepo);
 	});
 
+	it("accepts case-only differences between explicit `repo` and a run URL repo (PR #1951)", async () => {
+		const targetRepo = "cagedbird043/cxf";
+		const runUrlRepo = "CagedBird043/CXF";
+		const runId = 123;
+		const jsonSpy = vi
+			.spyOn(git.github, "json")
+			.mockResolvedValueOnce({
+				id: runId,
+				name: "CI",
+				display_title: "case-only run URL repo match",
+				status: "completed",
+				conclusion: "success",
+				head_branch: "main",
+				created_at: "2026-06-05T10:00:00Z",
+				updated_at: "2026-06-05T10:05:00Z",
+				html_url: `https://github.com/${runUrlRepo}/actions/runs/${runId}`,
+			})
+			.mockResolvedValueOnce({ total_count: 0, jobs: [] });
+		const textSpy = vi
+			.spyOn(git.github, "text")
+			.mockRejectedValue(new Error("gh repo view must not be consulted when `repo` is explicit"));
+
+		const tool = new GithubTool(createSession("/tmp/run-watch-run-url-casing"));
+		const result = await tool.execute("run-watch", {
+			op: "run_watch",
+			repo: targetRepo,
+			run: `https://github.com/${runUrlRepo}/actions/runs/${runId}`,
+		});
+		const text = result.content[0]?.type === "text" ? result.content[0].text : "";
+
+		expect(textSpy).not.toHaveBeenCalled();
+		for (const call of jsonSpy.mock.calls) {
+			const argv = call[1];
+			const apiPath = argv.find(arg => arg.startsWith("/repos/"));
+			expect(apiPath).toContain(`/repos/${targetRepo}/`);
+		}
+		expect(text).toContain(`Repository: ${targetRepo}`);
+		expect(result.details?.repo).toBe(targetRepo);
+	});
+
+
 	it("fails fast when explicit `repo` differs from the cwd repo and no `branch`/`run` selector is given (issue #1949)", async () => {
 		// Without a selector, the legacy code grabbed the cwd's HEAD SHA and
 		// queried it against the explicit repo — yielding an unrelated commit