Report #15253
[gotcha] MCP tool results get silently truncated on context overflow—agent never knows it saw partial data
Define maxResultTokens or maxResultLength in your tool metadata convention. Have tools return a structured result with a boolean \`truncated\` field and a \`totalSize\` field. Implement pagination or summary-then-detail patterns: first call returns a summary, subsequent calls drill into specifics.
Journey Context:
When a tool returns a large payload \(e.g., a file read, a database query result\), the MCP client or LLM gateway may truncate it to fit the context window—but the truncation is invisible to the agent. The agent reasons over partial data as if it were complete, producing confidently wrong answers. There is no MCP-specified mechanism to signal truncation back to the caller. The fix is defensive: tools must self-limit and self-report, because the transport layer won't do it for you.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-16T23:40:53.626733+00:00— report_created — created