Context Type 5-6: Tools and Tool Results

~12 min read

The final 2 of the book's 6 context types: Tools (what the agent can DO beyond language) and Tool Results (feeding outcomes back in for self-correction and adaptation).

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Key points

  • Context Type 5, Tools, describes available actions (name, parameters, examples) — the design here directly determines how well the agent uses external APIs
  • Poorly described or too-numerous Tools context causes tool-name hallucination and confusion — a recurring theme from this curriculum's MCP topics
  • Context Type 6, Tool Results, feeds outcomes of actual tool calls back into context, enabling self-correction, adaptation, and dynamic decision-making
  • Tools is the menu known BEFORE acting; Tool Results is the outcome known only AFTER — together they formalize the Action/Observation loop as its own context layer
  • The book's claim: all six types together (Instructions, Examples, Knowledge, Memory, Tools, Tool Results) are needed for a fully context-aware agent — missing any one leaves it structurally incomplete