fix: bound slack interactive button urls

steipete · steipete · commit 11d8ba96f9b1 · 2026-04-30T03:32:11.000+01:00
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -39,6 +39,7 @@ Docs: https://docs.openclaw.ai
 - Slack/commands: keep native command argument menus on select controls for encoded choice values up to Slack's option limit and truncate fallback button labels to Slack's button-text limit, so long valid choices no longer render invalid Slack blocks. Thanks @slackapi.
 - Agents/Codex: flush accepted debounced steering messages before normal app-server turn cleanup, so inbound follow-ups acknowledged as queued are not dropped when the turn completes before the debounce fires. Thanks @vincentkoc.
 - Slack/interactive replies: keep rendered buttons and selects within Slack Block Kit value and count limits, and align command argument select values with Slack's option limit, so overlong agent-authored choices no longer make Slack reject the whole block payload. Thanks @slackapi.
+- Slack/interactive replies: drop overlong Block Kit button URLs while preserving valid callback values, so malformed link buttons no longer make Slack reject the whole interactive reply. Thanks @slackapi.
 - CLI/update: scope packaged Node compile caches by OpenClaw version and install metadata, so global installs no longer reuse stale compiled chunks after package updates. Thanks @pashpashpash.
 - Channels/Voice call: keep pre-auth webhook in-flight limiting active when socket remote address metadata is missing, so slow-body requests from stripped-IP proxy paths still share the fallback bucket. (#74453) Thanks @davidangularme.
 - Plugin SDK/testing: lazy-load TypeScript from the plugin test-contract runtime and add release checks for critical SDK contract entrypoint imports and bundle size, so published packages fail preflight before shipping ESM-incompatible or oversized contract helpers. Thanks @vincentkoc.
diff --git a/extensions/slack/src/blocks-render.ts b/extensions/slack/src/blocks-render.ts
@@ -15,6 +15,7 @@ const SLACK_SECTION_TEXT_MAX = 3000;
 const SLACK_PLAIN_TEXT_MAX = 75;
 const SLACK_OPTION_VALUE_MAX = 75;
 const SLACK_BUTTON_VALUE_MAX = 2000;
+const SLACK_BUTTON_URL_MAX = 3000;
 const SLACK_STATIC_SELECT_OPTIONS_MAX = 100;
 const SLACK_ACTION_BLOCK_ELEMENTS_MAX = 25;
 
@@ -72,7 +73,11 @@ export function buildSlackInteractiveBlocks(interactive?: InteractiveReply): Sla
             button.value && isWithinSlackLimit(button.value, SLACK_BUTTON_VALUE_MAX)
               ? button.value
               : undefined;
-          if (!value && !button.url) {
+          const url =
+            button.url && isWithinSlackLimit(button.url, SLACK_BUTTON_URL_MAX)
+              ? button.url
+              : undefined;
+          if (!value && !url) {
             return [];
           }
           const style = resolveSlackButtonStyle(button.style);
@@ -86,7 +91,7 @@ export function buildSlackInteractiveBlocks(interactive?: InteractiveReply): Sla
                 emoji: true,
               },
               ...(value ? { value } : {}),
-              ...(button.url ? { url: button.url } : {}),
+              ...(url ? { url } : {}),
               ...(style ? { style } : {}),
             },
           ];
diff --git a/extensions/slack/src/shared-interactive.test.ts b/extensions/slack/src/shared-interactive.test.ts
@@ -164,6 +164,34 @@ describe("buildSlackInteractiveBlocks", () => {
     expect(buttonBlock.elements?.[1]).not.toHaveProperty("value");
   });
 
+  it("drops Slack button URLs beyond Block Kit limits", () => {
+    const validUrl = `https://example.com/${"a".repeat(2980)}`;
+    const longUrl = `https://example.com/${"b".repeat(2981)}`;
+    const blocks = buildSlackInteractiveBlocks({
+      blocks: [
+        {
+          type: "buttons",
+          buttons: [
+            { label: "Allowed", url: validUrl },
+            { label: "Too long", url: longUrl },
+            { label: "Fallback action", value: "fallback", url: longUrl },
+          ],
+        },
+      ],
+    });
+
+    const buttonBlock = blocks[0] as {
+      elements?: Array<{ value?: string; url?: string }>;
+    };
+
+    expect(validUrl).toHaveLength(3000);
+    expect(longUrl).toHaveLength(3001);
+    expect(buttonBlock.elements).toHaveLength(2);
+    expect(buttonBlock.elements?.[0]?.url).toBe(validUrl);
+    expect(buttonBlock.elements?.[1]?.value).toBe("fallback");
+    expect(buttonBlock.elements?.[1]).not.toHaveProperty("url");
+  });
+
   it("caps Slack actions blocks at the Block Kit element limit", () => {
     const blocks = buildSlackInteractiveBlocks({
       blocks: [
