diff --git a/CHANGELOG.md b/CHANGELOG.md
index 723771cf6..9c201c0a6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -24,6 +24,7 @@
 - WhatsApp: route queued replies to the original sender instead of the bot's own number. (#534) — thanks @mcinteerj
 - Models: add OAuth expiry checks in doctor, expanded `models status` auth output (missing auth + `--check` exit codes). (#538) — thanks @latitudeki5223
 - Deps: bump Pi to 0.40.0 and drop pi-ai patch (upstream 429 fix). (#543) — thanks @mcinteerj
+- Agent: skip empty error assistant messages when rebuilding session context to avoid tool-chain corruption. (#561) — thanks @mukhtharcm
 - Security: per-agent mention patterns and group elevated directives now require explicit mention to avoid cross-agent toggles.
 - Config: support inline env vars in config (`env.*` / `env.vars`) and document env precedence.
 - Agent: enable adaptive context pruning by default for tool-result trimming.
diff --git a/package.json b/package.json
index 593b0d2da..671bd5228 100644
--- a/package.json
+++ b/package.json
@@ -210,7 +210,7 @@
   "patchedDependencies": {
     "@mariozechner/pi-agent-core": "patches/@mariozechner__pi-agent-core.patch",
     "@mariozechner/pi-coding-agent": "patches/@mariozechner__pi-coding-agent.patch",
-      "@mariozechner/pi-ai": "patches/@mariozechner__pi-ai.patch",
+    "@mariozechner/pi-ai": "patches/@mariozechner__pi-ai.patch",
     "qrcode-terminal": "patches/qrcode-terminal.patch",
     "playwright-core@1.57.0": "patches/playwright-core@1.57.0.patch"
   }
diff --git a/patches/@mariozechner__pi-ai.patch b/patches/@mariozechner__pi-ai.patch
index 92a7b9087..65b206c74 100644
--- a/patches/@mariozechner__pi-ai.patch
+++ b/patches/@mariozechner__pi-ai.patch
@@ -2,14 +2,13 @@ diff --git a/dist/providers/google-gemini-cli.js b/dist/providers/google-gemini-
 index 0000000..1111111 100644
 --- a/dist/providers/google-gemini-cli.js
 +++ b/dist/providers/google-gemini-cli.js
-@@ -248,6 +248,13 @@ async function* streamGeminiCli(model, context, credentials, options) {
+@@ -248,6 +248,12 @@ async function* streamGeminiCli(model, context, credentials, options) {
                          break; // Success, exit retry loop
                      }
                      const errorText = await response.text();
-+                    // PATCH: Fail immediately on 429 to let caller rotate accounts
++                    // PATCH: Fail immediately on 429 for Antigravity to let caller rotate accounts.
 +                    // Antigravity rate limits can have very long retry delays (10+ minutes).
-+                    // Instead of waiting, throw immediately so clawdbot can rotate to another account.
-+                    if (response.status === 429) {
++                    if (isAntigravity && response.status === 429) {
 +                        console.log(`[pi-ai] 429 rate limit - failing fast to rotate account`);
 +                        throw new Error(`Cloud Code Assist API error (${response.status}): ${errorText}`);
 +                    }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 361e2b677..ff1f71889 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -12,7 +12,7 @@ patchedDependencies:
     hash: 01312ceb1f6be7e42822c24c9a7a4f7db56b24ae114a364855bd3819779d1cf4
     path: patches/@mariozechner__pi-agent-core.patch
   '@mariozechner/pi-ai':
-    hash: a64d167efc76cfc0504fa6ce9e9643276ee41020f9c82e7ed0c763c4af290811
+    hash: 3f4c1f943c57dbe2980bf21b1768dc780355f9124eeffbc30b5d5e42d2ea4b7c
     path: patches/@mariozechner__pi-ai.patch
   '@mariozechner/pi-coding-agent':
     hash: 58af7c712ebe270527c2ad9d3351fac39d6cd4b81cc475a258d87840b446b90e
@@ -42,7 +42,7 @@ importers:
         version: 0.41.0(patch_hash=01312ceb1f6be7e42822c24c9a7a4f7db56b24ae114a364855bd3819779d1cf4)(ws@8.19.0)(zod@4.3.5)
       '@mariozechner/pi-ai':
         specifier: ^0.41.0
-        version: 0.41.0(patch_hash=a64d167efc76cfc0504fa6ce9e9643276ee41020f9c82e7ed0c763c4af290811)(ws@8.19.0)(zod@4.3.5)
+        version: 0.41.0(patch_hash=3f4c1f943c57dbe2980bf21b1768dc780355f9124eeffbc30b5d5e42d2ea4b7c)(ws@8.19.0)(zod@4.3.5)
       '@mariozechner/pi-coding-agent':
         specifier: ^0.41.0
         version: 0.41.0(patch_hash=58af7c712ebe270527c2ad9d3351fac39d6cd4b81cc475a258d87840b446b90e)(ws@8.19.0)(zod@4.3.5)
@@ -3783,7 +3783,7 @@ snapshots:
 
   '@mariozechner/pi-agent-core@0.41.0(patch_hash=01312ceb1f6be7e42822c24c9a7a4f7db56b24ae114a364855bd3819779d1cf4)(ws@8.19.0)(zod@4.3.5)':
     dependencies:
-      '@mariozechner/pi-ai': 0.41.0(patch_hash=a64d167efc76cfc0504fa6ce9e9643276ee41020f9c82e7ed0c763c4af290811)(ws@8.19.0)(zod@4.3.5)
+      '@mariozechner/pi-ai': 0.41.0(patch_hash=3f4c1f943c57dbe2980bf21b1768dc780355f9124eeffbc30b5d5e42d2ea4b7c)(ws@8.19.0)(zod@4.3.5)
       '@mariozechner/pi-tui': 0.41.0
     transitivePeerDependencies:
       - '@modelcontextprotocol/sdk'
@@ -3793,7 +3793,7 @@ snapshots:
       - ws
       - zod
 
-  '@mariozechner/pi-ai@0.41.0(patch_hash=a64d167efc76cfc0504fa6ce9e9643276ee41020f9c82e7ed0c763c4af290811)(ws@8.19.0)(zod@4.3.5)':
+  '@mariozechner/pi-ai@0.41.0(patch_hash=3f4c1f943c57dbe2980bf21b1768dc780355f9124eeffbc30b5d5e42d2ea4b7c)(ws@8.19.0)(zod@4.3.5)':
     dependencies:
       '@anthropic-ai/sdk': 0.71.2(zod@4.3.5)
       '@google/genai': 1.34.0
@@ -3817,7 +3817,7 @@ snapshots:
     dependencies:
       '@mariozechner/clipboard': 0.3.0
       '@mariozechner/pi-agent-core': 0.41.0(patch_hash=01312ceb1f6be7e42822c24c9a7a4f7db56b24ae114a364855bd3819779d1cf4)(ws@8.19.0)(zod@4.3.5)
-      '@mariozechner/pi-ai': 0.41.0(patch_hash=a64d167efc76cfc0504fa6ce9e9643276ee41020f9c82e7ed0c763c4af290811)(ws@8.19.0)(zod@4.3.5)
+      '@mariozechner/pi-ai': 0.41.0(patch_hash=3f4c1f943c57dbe2980bf21b1768dc780355f9124eeffbc30b5d5e42d2ea4b7c)(ws@8.19.0)(zod@4.3.5)
       '@mariozechner/pi-tui': 0.41.0
       chalk: 5.6.2
       cli-highlight: 2.1.11