From cd358482b86b7ad3ff781d0fececfb188f572600 Mon Sep 17 00:00:00 2001
From: bradAGI <46579244+bradAGI@users.noreply.github.com>
Date: Mon, 24 Aug 2026 14:31:56 -0400
Subject: [PATCH] feat(google_adk): add ADK-112, workflow agent has no
 description
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adk_sequential_agent, adk_parallel_agent, and adk_langgraph_agent are
valid applies_to tokens the engine discovers but no shipped rule used —
every ADK agent-scope rule targets adk_llm_agent, except ADK-108 for
LoopAgent. This covers the workflow classes for the routing check
ADK-101 already makes for LlmAgent.

A workflow agent is routed to exactly like an LlmAgent: the parent's
model sees only the child's description. It is easier to miss here,
because a workflow agent has no instruction= and no model= of its own, so
nothing else about its construction reads as model-facing text. What it
orchestrates is also invisible from outside — the parent cannot infer
"runs these three steps in order" from the class name.

Left adk_langgraph_agent out: LanggraphAgent takes a compiled graph
rather than an ADK sub_agents tree, so the delegation-routing argument
does not transfer without checking how the engine models it.
---
 google_adk/agent_safety.yaml | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/google_adk/agent_safety.yaml b/google_adk/agent_safety.yaml
index 8854126..a4ef412 100644
--- a/google_adk/agent_safety.yaml
+++ b/google_adk/agent_safety.yaml
@@ -282,3 +282,39 @@ rules:
       Pass a `description` in the `new LlmAgent({...})` options that names this
       agent's role and the kind of input it handles. One sentence is enough; treat
       it as documentation the parent agent's model reads to route.
+
+  - id: ADK-112
+    title: Workflow agent has no description
+    severity: medium
+    confidence: 0.85
+    language: python
+    applies_to:
+      - adk_sequential_agent
+      - adk_parallel_agent
+      - adk_loop_agent
+    scope: agent
+    match:
+      all:
+        - agent_class: [SequentialAgent, ParallelAgent, LoopAgent]
+        - agent_kwarg_missing: [description]
+    explanation: >
+      Google ADK routes delegation using the description= field on each agent in
+      a sub_agents tree, and a workflow agent is routed to exactly like an
+      LlmAgent is: when the parent decides whether to hand off, the model sees
+      only the child's description. A SequentialAgent, ParallelAgent, or
+      LoopAgent with no description sits in the tree but gives the parent's model
+      no signal to pick it, so it is effectively unreachable through delegation
+      — a silent routing bug, not an error. It is easier to miss on a workflow
+      agent than on an LlmAgent: a workflow agent has no instruction= and no
+      model= of its own, so nothing else about its construction reads as
+      model-facing text and the missing description does not look like an
+      omission. What the agent orchestrates is also invisible from the outside —
+      the parent cannot infer "runs these three steps in order" from the class
+      name alone.
+    fix: >
+      Add a description= kwarg naming what the workflow accomplishes and the
+      kind of input it expects, not its mechanics — the parent's model is
+      choosing whether this branch is the right one, so "drafts, reviews, and
+      revises a support reply" routes correctly where "sequential agent" does
+      not. One sentence is usually enough. Treat it as documentation for the
+      parent agent's model.