LLM hallucinated URL, bypassed validation, and returned empty card

A developer encountered an issue where a language model hallucinated a URL for a recipe, which was then processed without error, resulting in an empty recipe card. The model generated the URL from its training data rather than retrieving it from a reliable source. This occurred because the system's validation checks focused on the URL's format rather than its actual existence, and the tool used to fetch the content did not return an error for a non-existent page. The fix involves updating the system to specifically check for a 'not found' template on the target website and to ensure that any resource identifier used in a tool call is directly present in the user's prompt or a previous tool result. AI

IMPACT Highlights a common failure mode in LLM agents where hallucinated resource identifiers can bypass validation, leading to silent errors and underscoring the need for robust grounding checks.

RANK_REASON This is a technical post about a specific bug in an LLM application's handling of hallucinated URLs and the proposed fix.

Read on dev.to — LLM tag →

• Bitsfolio
• Cheerio
• ctx.fetchStatic
• Hallucinated Tool Argument That Passed Schema Validation
• MCP-servers/Vodou-Console/src/lenses/recipe.allrecipes/index.ts
• src/lenses/_lib/fetch_ctx.ts
• src/llm.ts

• product
• other

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