{"version":"2.1.312","anchor":"mcp-tool-output-encoder-tries-smaller-forms-before-failing","canonical_anchor":"mcp-tool-output-encoder-tries-smaller-forms-before-failing","heading":"MCP tool results try smaller forms before giving up","tier":"notice","area":"MCP","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.312\/e\/mcp-tool-output-encoder-tries-smaller-forms-before-failing","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.312","markdown":"### MCP tool results try smaller forms before giving up\n\nWhen building an MCP tool result fails or is too big, Claude Code now tries smaller forms and fails only if none of them fit\n\n**What**\n\nAn MCP tool is a tool provided through an MCP server, a connector that gives Claude extra tools. When Claude Code builds the answer to an MCP tool call, it now tries each possible form of the result one at a time. It returns the first form that fits the size limit. If one form fails to build, Claude Code logs the failure and moves on to a smaller form.\n\nIt reports `result_too_large` only when no form fits. Before, any error while building the result failed the whole call with `result_unbuildable`.\n\n**Why**\n\nA problem with one form of the result no longer throws away the whole MCP tool result.\n\n- Area: MCP\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 1\/5\n- Scope: individual\n- Heads-up: no"}