René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[FEATURE] MCP server: provide a JSON render option for tool result text content","articleBody":"## Summary\n\nMCP tool results from `stackql mcp` currently carry the typed payload in\n`structuredContent` and a markdown rendering in the `text` content block\n(`pkg/mcp_server/render`). That is spec-correct, but a large class of MCP\nclients - LLM hosts, scripting clients, and SDK helpers - only consume the\n`text` content. For those clients the markdown table/KV rendering is lossy\nand unparseable, and there is no way to opt into machine-readable text.\n\n## Current behavior\n\n`tools/call run_select_query` returns:\n\n- `structuredContent`: `{\"rows\": [...]}` (typed DTO)\n- `content[0].text`: a markdown table (`RenderTable`) or KV records\n  (`RenderKV`), e.g. `# Pull Result\\n\\n## Record 1\\n...`\n\n## Proposed enhancement\n\nEither (or both) of:\n\n1. A per-call argument on the query/metadata tools, e.g.\n   `format: \"markdown\" | \"json\"` (default `markdown`, preserving current\n   behavior), where `json` renders the same DTO as compact JSON into the\n   text content block:\n\n   ~~~json\n   {\n     \"name\": \"run_select_query\",\n     \"arguments\": {\"sql\": \"SELECT 1\", \"format\": \"json\"}\n   }\n   ~~~\n\n2. A server-level render default in `--mcp.config`, consistent with the\n   existing config surface:\n\n   ~~~json\n   {\"server\": {\"render\": \"json\", \"audit\": {\"disabled\": true}}}\n   ~~~\n\nThe per-call argument is the more useful of the two for mixed workloads\n(human-facing hosts want markdown, embedded/scripting clients want JSON in\nthe same session).\n\n## Context\n\nEncountered while building the embedded Rust client (`stackql-mcp-rs`):\nclients that follow the MCP spec can and should prefer `structuredContent`\n(that is what we ship), but interop with text-only consumers currently\nrequires parsing markdown. Observed on stackql v0.10.500, MCP stdio mode.\n","author":{"url":"https://github.com/jeffreyaven","@type":"Person","name":"jeffreyaven"},"datePublished":"2026-06-13T01:10:02.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/669/stackql/issues/669"}