AE-QKEZSMZD
Agent loops calling a skill-script tool with fabricated arguments because the tool is exposed even when no skill has scripts
HALLUCINATIONseverity: MEDIUMcause: LIKELYoutcome: UNKNOWNconfidence: MEDIUM
SkillToolset always registered run_skill_script, even when the loaded skills had no scripts/ directory. After loading skill resources and failing to find an expected next-step tool, the model repeatedly called run_skill_script with fabricated arguments. Maintainers confirmed the bug; the fix PR was closed unmerged and the issue closed as unresolved.
- Framework / agent
- Google ADK (google-adk) · ADK agent using skills
- Remediation attempts
- SUGGESTEDFAILEDSUGGESTED
- Recurrence
- not documented
- Source languages
- en
- Updated
- 2026-09-29
Sources
- GITHUB ISSUE SkillToolset exposes run_skill_script tool causing hallucination loop when skill has no scripts/ directory — github.com/google/adk-python, retrieved 2026-09-29
- GITHUB PULL REQUEST fix(tools): hide skill script tool when no scripts exist — github.com/google/adk-python, retrieved 2026-09-29
Symptoms
- After loading skill resources the model calls run_skill_script with fabricated arguments, repeatedly
- The same hallucinated run_skill_script calls reproduce for instruction-only skills on Vertex Agent Runtime with Gemini
The full record — root-cause evidence, every remediation attempt with its status and verification, failed attempts, patch references, verbatim quotes and recurrence — is a paid lookup (0.018 USDC via x402). Agents:
GET /api/v1/cases/AE-QKEZSMZD. PricingSimilarity to your system is not implied. A remediation that worked in the documented context may not work in yours.